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The pollution of rivers
306
THE
POLLUTION
London from the Thames and Lee, and the chalk wells, is, by comparison, poor and inadequate. The most recently built block of artisans' dwellings in Lisson Grove provides a full-length bath for each set of rooms ; this wilt doubtless be the future method of building for the artizan class, and will entail, as a necessity, a far larger daily supply than thirty-one gallons per head. The Liverpool scheme is said to have only cost ;~I,8O2,9o 9. There is no difficulty in conveying water long distances; with this latest example of engineering skill before us, we hope to see the question of a water supply suitable to the greatness, wealth, and population of the metropolis, revived.
THE POLLUTION
OF RIVERS.
TH~ ~7th Annual Report of the Inspector of Fisheries again calls attention to the fact already notorious, that legislative attempts to restore purity to our streams have been hitherto absolute failures. Mr. Berrington says : " A season like the last (I886) brings the state of our inland waters more clearIy home to the public than all that has been written or said upon the subject. The fact that few of our streams are in such a condition as to be available for human use has been in a great measure disguised, as regards the great towns, by the provision of reservoirs at the head waters, constructed at enormous expense. But when these reservoirs fail it is found that there is no other wholesome supply to fail back upon. I n the case of cattle, the water which was formerly merely injurious becomes deadly. I could give instances of animals raging with thirst and breaking oug of fields through which a river might be running, because the water of that river was su(h as they could not touch, and this even in ordinary seasons. I f such is the effect upon land animals, what must its results be to the fish? T h e manufacturing pollutions of the Yorkshire Ouse destroyed hundreds of salmon near Goole during the last summer. The disinfectants introduced into the sewage of Newcastle, and conveyed with it into the tideway, produced a similar result on the Tyne. A n occasional discharge from a lead mine poisons the fish of the Greta and the Cumberland Derwent for seven miles down to Bassenthwaite. T h e slime from a tin mine escapes into a Devonshire brook, and the salmon die in the Plym. T h e coal washing on the Ogmore has denuded that river of fish of all kinds. Even coarse fish are rarely found in the Derbyshire Derwent for sorre miles below the point of discharge o f the sewage of Derby. T h e salmon fisheries of the Ribble are yearly decreasing in value from the impurity of the stream. T h e waters of the Avon Ltwyd, when the tinplate trade is good, receive, in one form or another, some 2o tons of vitriol per week ; and, although they discharge into
OF
RIVERS.
the tideway, their pungency frequently turns back the salmon ascending the Usk. " I f it were merely a question between the existence of manufactures or the economical drainage of towns on the one side, and the existence of fish on the other, the fish would reasonably be sacfiriced. But this is not so, and now that it has become a question of public health and life, it is to be hoped that some efficient steps may be taken to prevent the contamination of the entire freshwaters of the country. These steps would not involve any real injury to the manufacturers. It may be inconvenient to t h e m , - - a n d certainly there is a disinclination on their p a r t , - - t o introduce additional processes at their works ~ but in nearly every case a purifying process is available, in many its adoption may be made a source of profit, and in very few need the expense be serious." Mr. Fryer says : " S o long as the estuary of the Thames remains in its present polluted state, it is hopeless to expect that it wilt ever resume its former place in the list of salmon rivers. T h e upper waters of the Thames are comparativeIy pure, but the filthy state of the tidal waters remains a c o m p l e t e - - a n d probably the only. practic a I - - b a r to the re-introduction of migratory salmonidze. " T h e total area of England and Wales is about 56,0oo square miles, and the streams draining some 9,000 square miles are practically denuded of fish of any kind by reason of the pollutions which are poured into them. I n some cases whole watersheds are thus destroyed, the most notable cases being those of the Bristol Avon, draining 890 square miles ; the Mersey, draining 885 square miles; the Aire and Calder, draining 8I 5 square miles ; the Weaver, d~aining 7io square miles ; the Don, draining 682 square miles ~ the Taft, draining I98 square miles ; the Ogmore, draining i 8 o square miles; the Loughor, draining I56 square miles ; the Neath, draining i iS square m i l e s , the Tawe, draining ~o6 square miles ; and the E b b w and Sirhowy, draining i o o square miles. T h e injury caused by the condition of these rivers becomes all the greater when it is remembered that while a considerable proportion of the total area of the country is actually devoid of fish-producing streams, and a still further proportion is watered by rivers whose fisheries would at the best be of very slight value, alI the rivers above mentioned have great natural fish-producing capabilities, and the majority of them would, if they were restored to a state of purity, produce fish of the highest value. " H o p e l e s s l y ruined as the fisheries of the above rivers are, and must remain, so long as they continue to be used as mere conduits for foul liquids, or as places for the deposit of waste substances generally,--their waters discoloured and poisoned, and their beds and banks coated in some cases to a depth of several feet with solid refuse more or
THE
POLLUTION
less pestiferous,--there is no reason why they should not be restored by the operation of an efficient law for preventing the continuance of their pollution. On the other hand, there is every reason to fear that the above list will have to be !engthened if, in the absence of any such law, any considerable increase of commercial activity should occur. There is hardly a river in the country that can be said to be even moderately ' pure ' throughout its whole course, and there are very few important watersheds some portions of which are not destroyed for fishery purposes by pollutions. The Ribble, the Dee, the Towy, the Usk, the Wye, the Severn, the Trent, the Tees, the Wear, and the Tyne,--aI1 producing salmon, trout, and other fish - - a r e fed by tributaries whose waters are so foul as to be entireIy unable to contribute their quota to the stock of fish in their respective watersheds. If the evil ended there it would not be so serious as it is ; but these tributaries are a constant cause of the destruction of fish in the rivers into which they run. " ' T o w n sewage' must be added to the list of pollutions. I do not propose in this report taking any part in the ' odium sewagia~m,' but to limit myself to pointing out generally the injurious effect on the fisheries of river pollution, more particularly from factory and mine refuse, and to show that in most if not in all cases the practice of casting such refuse into the rivers is not only injurious to the fisheries, but that its prevention is easy, and that in many instances remedies are available which would more than repay--in the utilization of the waste products--the cost of prevention. " T h e fact is fl'equently overlooked that the solu. tion o f the sewage problem would be rendered more easy if manufacturing refuse were kept distinct from sewage properly so called. Under the present system it is difficult to define what is and what is not 'sewage.' Without for a moment admitting that a river is the proper place for the disposal of sewage, even in its most harmless state, "~ it cannot be denied that when it is not contaminated by manufacturing refuse, and when it is discharged in a fresh state into a sufficient volume of water, it is less hurtful to the fisheries than many forms of pollution which receive less attention at the hands of sanitarians and others who are interested in river purification. But ' t o w n sewage' is generally more or less mixed with refuse from manu~There the argument is used--as it commonlyis--that to pour sewage into a river cannot be hurtful, trot rather an advantage, to the fisheries because the finest fish are often found feediDgat the mouths of drains, it is forgotten that this only occurs where the sewage is fresh and the quantity small compared with the volume of water in the stream and the nmnber of fishcontainedin it ; whereas town sewage in most cases reaches a river, not only in large quantities, but in a more or less advanced state of fermentation. The fresher the sewage when it enters a river the Iurther away from the outfall must its deleteriouseftects he sought in the abstraction of oxygen from the water, and in the development of the well-knownsewage fungus, and otherwise.
OF
RIVERS.
307
factories which are allowed to drain into the sewers. I n some cases this refuse matter possesses properties which, if it were mixed with sewage in due proportions and under proper conditions, would serve as a precipitant and deodorant ; in others, manufacturing refuse contains so large a percentage of highly fertilizing matter that its addition to ordinary sewage would largely increase the value of the latter for irrigation purposes : but in many instances these extraneous matters are such as not only to make the discharge of" sewage" into the rivers more undesirable than ever, but to render it totally unfit to be applied to the land ir~ any form. A curious incidence of the added danger which ' sewage ' may contain when turned into a river is afforded by the report of the T y n e Board of Conservators, who state that a "most serious i n j u r y ' was caused to the fisheries in the tidal basin of that river ' b y the Corporation of Newcastle having "disinfected" Byker Burn with caustic soda as one chief ingredient. A smal~ flood took place at the end of July when the river was exceptionally low and the tides not high, the result being that this poisonous material was carried into the Tyne, and . . . every kind of fish for eleven miles of the tideway was destroyed. So poisonous was the ingredient that the fishermen's nets were tainted.' This case is further interesting as illustrating a defect in the Rivers. Pollution Act, which, so tar as I am aware, has escaped observation, but which would at once come into prominence if any general attempt were made to put that Act into active operation. While the Act professes to prohibit the discharge of any sewage matter ' or other ' polluting l i q u i d ' into a stream, it permits--subject to certain provisoes, which have been found practically worthless, as to the adoption of the ' best practicable and reasonably available m e a n s ' for rendering harmless the polluting matter - - the continued discharge of such matter or liquid if the channel by which it is carried was 'used, constructed, or in process of construction ' at the date of the passing of the Act. The sewage or other polluting liquid may have been comparatively harmless, both in quality and quantity, at that time, whereas, since then it may have multiplied many times in volume and virulence. I n other words, however much a town may have increased its population, however many new factories may pour their refuse into the drains, the sanitary authorities are practically held innocent of doing more harm than they did before i876 , provided they turn their 'sewage' into the river through the old exit; or a manufacturer who was doing no practical harm in I876 may ruin a river with impunity in i888 if he uses the original channels for the discharge of the same kind of refuse ; or a dozen manufacturers, who would each be liable to the prohibitions contained in the Act if they constructed new outlets for their refuse, may pollute the river without fear of any real inter•
.
.
SoY
THE
PI!EVENTiON
ference if they make common use of a drain that happened to be in use by one of them in x876. " T h e severaI forms of pollution from mines and factories differ in quality and quantity in different rivers, and the effects of the various matters contained in them are very diverse. Although it is ~suaI so to speak of fish killed by polluted water as having been ' poisoned,' it is a question whether that expression is always strictly correct. That fish are poisoned in the common meaning of the word by the action of irritants taken into the stomach is probably a very rare occurence ; it is possibly hardly tess seldom that they are killed by the absorption of poison into the blood. This is probably the case where arsenic is present in the water, the poison being absorbed and carried into the system with the oxygen. The more frequent cases in which fish can be said to be "poisoned' are those in which an effect analogous to ' skin poisoning' is produced by the action of caustic liquors on the delicate branchiae. Even in such cases the ultimate cause of death is suffocation, owing to the derangement of the functions of the breathing organs. I n all other instances fish are directly suffocated either through the gills becoming clogged by the deposit on them of matters in suspension in the water, or by the water being itself deprived of oxygen by matters either in suspension or in solution in it. An instance of suffocation of fish in the manner last mentioned may be found in the ease of rivers rendered ochreous by the decomposition of iron pyrites. The pollution of rivers by china clay affords a typical illustration of simple suffocation of fish by the mechanical clogging of the gills ; while in the effect of caustic soda may be seen the joint effects of ' poisoning' and suffoca~tion. " B u t not less serious than the actual destruction o f fish is the injury caused to the spawning beds and eggs by the gradual deposit of the matters held in suspension in the liquids discharged from sewers, mines, and manufactories, and by the solid refuse cast either directly into the streams or so close to the banks as to be liable to be washed away by floods; while the destruction of weeds and of insects and other life forming the food of fish is a further aggravation of the evil. "Year after year Boards of Conservators complain o f the inadequacy of the powers conferred upon them, or, indeed, upon any other authority, to prevent these evils. Referring to tbe fact that proceedings under the Rivers Pollution Act can only be taken by sanitary authorities, the Trent Board .ask for ' some cheap and expeditious mode of compelling authorities (called sanitary) and others to desist from polluting streams.' The Pollution Act is ' utterly unworkable and useless ' say the Board of Conservators of the Rhymney Fishery District in reply to the inquiry whether they have taken steps during the past year to prevent pollutions ; the Usk Board similarly represent that ' an altera-
OF
~.~Tore ~.......i x-~t .oxo.
tion in the law which would facilitate prosecutions for pollution is much needed, the existing law being practically useless and unworkable ;' while the Tyne Board declare the Act to be a ' failure.' This opinion is but the echo of the view entertained by Boards of Conservators throughout the country, after twelve years' experience ot the working of that Act. In many cases the polluted state of the rivers is the only impediment, or at least the most serious impediment, to the deveIopment of the fisheries." THE
PREVENTION
OF
PHTHISIS.
By J. EDWARD SQUIRE, M.D.Lond., M.R.C.P., Physician to the North London Consumption Hospital. (Read on Jamta~'y 9NG 1889, before t~e E~idemiolagic~l
Society. )
PHTHISIS is shown, by the annual returns of the Registrar-General, to be one of the most frequent causes of death in this country, more especially during the working period of life, viz., between the ages of x 5 and 6 5 years. If, then, it can be shown to depend upon conditions which are under human cov,trol, it is obviously to the interest of the community that a systematic attempt should be made to diminish, and where possible remove, the preventible causes of this disease. In the present paper, facts are brought together which prove the influence on the prevalence of phthisis of conditions which come within the scope of preventive medicine, and tend to show that much of the mortality from this disease might be prevented by due attention to hygiene and sanitation. Experiments have abundantly proved that tubercular disease can be communicated from affected animals to the healthy ; the communicability of consumption has long been a matter of popular belief, and cases are referred to which seem to prove this point. The dependence of tuberculosis upon the infective bacillus has also been shown by numerous experiments. Phthisis, then, depends primarily upon the reception into the body of an infective particle or micro-organism--the bacillus tuberculosis--and is thus in close relation with the infectious diseases, towards the control of which preventive medicine has already done so much. Amongst the various modes by which the infecting bacillus has been shown to enter the body, there are two which are of special importance in connection with the subject of this paper. Communication by means of the mucous membrane of the alimentary canal is of interest, because of the prevalence of tuberculosis in cattle, and from the experimental proof of the infectivehess of the milk of tuberculous cows. As animals which are crowded together in sheds with deficient ventilation are most liable to tuberculosis, an efficient inspection of cattle kept for dairy purposes is necessary. Although the injurious properties of the milk of diseased animals may be destroyed by
THE
POLLUTION
London from the Thames and Lee, and the chalk wells, is, by comparison, poor and inadequate. The most recently built block of artisans' dwellings in Lisson Grove provides a full-length bath for each set of rooms ; this wilt doubtless be the future method of building for the artizan class, and will entail, as a necessity, a far larger daily supply than thirty-one gallons per head. The Liverpool scheme is said to have only cost ;~I,8O2,9o 9. There is no difficulty in conveying water long distances; with this latest example of engineering skill before us, we hope to see the question of a water supply suitable to the greatness, wealth, and population of the metropolis, revived.
THE POLLUTION
OF RIVERS.
TH~ ~7th Annual Report of the Inspector of Fisheries again calls attention to the fact already notorious, that legislative attempts to restore purity to our streams have been hitherto absolute failures. Mr. Berrington says : " A season like the last (I886) brings the state of our inland waters more clearIy home to the public than all that has been written or said upon the subject. The fact that few of our streams are in such a condition as to be available for human use has been in a great measure disguised, as regards the great towns, by the provision of reservoirs at the head waters, constructed at enormous expense. But when these reservoirs fail it is found that there is no other wholesome supply to fail back upon. I n the case of cattle, the water which was formerly merely injurious becomes deadly. I could give instances of animals raging with thirst and breaking oug of fields through which a river might be running, because the water of that river was su(h as they could not touch, and this even in ordinary seasons. I f such is the effect upon land animals, what must its results be to the fish? T h e manufacturing pollutions of the Yorkshire Ouse destroyed hundreds of salmon near Goole during the last summer. The disinfectants introduced into the sewage of Newcastle, and conveyed with it into the tideway, produced a similar result on the Tyne. A n occasional discharge from a lead mine poisons the fish of the Greta and the Cumberland Derwent for seven miles down to Bassenthwaite. T h e slime from a tin mine escapes into a Devonshire brook, and the salmon die in the Plym. T h e coal washing on the Ogmore has denuded that river of fish of all kinds. Even coarse fish are rarely found in the Derbyshire Derwent for sorre miles below the point of discharge o f the sewage of Derby. T h e salmon fisheries of the Ribble are yearly decreasing in value from the impurity of the stream. T h e waters of the Avon Ltwyd, when the tinplate trade is good, receive, in one form or another, some 2o tons of vitriol per week ; and, although they discharge into
OF
RIVERS.
the tideway, their pungency frequently turns back the salmon ascending the Usk. " I f it were merely a question between the existence of manufactures or the economical drainage of towns on the one side, and the existence of fish on the other, the fish would reasonably be sacfiriced. But this is not so, and now that it has become a question of public health and life, it is to be hoped that some efficient steps may be taken to prevent the contamination of the entire freshwaters of the country. These steps would not involve any real injury to the manufacturers. It may be inconvenient to t h e m , - - a n d certainly there is a disinclination on their p a r t , - - t o introduce additional processes at their works ~ but in nearly every case a purifying process is available, in many its adoption may be made a source of profit, and in very few need the expense be serious." Mr. Fryer says : " S o long as the estuary of the Thames remains in its present polluted state, it is hopeless to expect that it wilt ever resume its former place in the list of salmon rivers. T h e upper waters of the Thames are comparativeIy pure, but the filthy state of the tidal waters remains a c o m p l e t e - - a n d probably the only. practic a I - - b a r to the re-introduction of migratory salmonidze. " T h e total area of England and Wales is about 56,0oo square miles, and the streams draining some 9,000 square miles are practically denuded of fish of any kind by reason of the pollutions which are poured into them. I n some cases whole watersheds are thus destroyed, the most notable cases being those of the Bristol Avon, draining 890 square miles ; the Mersey, draining 885 square miles; the Aire and Calder, draining 8I 5 square miles ; the Weaver, d~aining 7io square miles ; the Don, draining 682 square miles ~ the Taft, draining I98 square miles ; the Ogmore, draining i 8 o square miles; the Loughor, draining I56 square miles ; the Neath, draining i iS square m i l e s , the Tawe, draining ~o6 square miles ; and the E b b w and Sirhowy, draining i o o square miles. T h e injury caused by the condition of these rivers becomes all the greater when it is remembered that while a considerable proportion of the total area of the country is actually devoid of fish-producing streams, and a still further proportion is watered by rivers whose fisheries would at the best be of very slight value, alI the rivers above mentioned have great natural fish-producing capabilities, and the majority of them would, if they were restored to a state of purity, produce fish of the highest value. " H o p e l e s s l y ruined as the fisheries of the above rivers are, and must remain, so long as they continue to be used as mere conduits for foul liquids, or as places for the deposit of waste substances generally,--their waters discoloured and poisoned, and their beds and banks coated in some cases to a depth of several feet with solid refuse more or
THE
POLLUTION
less pestiferous,--there is no reason why they should not be restored by the operation of an efficient law for preventing the continuance of their pollution. On the other hand, there is every reason to fear that the above list will have to be !engthened if, in the absence of any such law, any considerable increase of commercial activity should occur. There is hardly a river in the country that can be said to be even moderately ' pure ' throughout its whole course, and there are very few important watersheds some portions of which are not destroyed for fishery purposes by pollutions. The Ribble, the Dee, the Towy, the Usk, the Wye, the Severn, the Trent, the Tees, the Wear, and the Tyne,--aI1 producing salmon, trout, and other fish - - a r e fed by tributaries whose waters are so foul as to be entireIy unable to contribute their quota to the stock of fish in their respective watersheds. If the evil ended there it would not be so serious as it is ; but these tributaries are a constant cause of the destruction of fish in the rivers into which they run. " ' T o w n sewage' must be added to the list of pollutions. I do not propose in this report taking any part in the ' odium sewagia~m,' but to limit myself to pointing out generally the injurious effect on the fisheries of river pollution, more particularly from factory and mine refuse, and to show that in most if not in all cases the practice of casting such refuse into the rivers is not only injurious to the fisheries, but that its prevention is easy, and that in many instances remedies are available which would more than repay--in the utilization of the waste products--the cost of prevention. " T h e fact is fl'equently overlooked that the solu. tion o f the sewage problem would be rendered more easy if manufacturing refuse were kept distinct from sewage properly so called. Under the present system it is difficult to define what is and what is not 'sewage.' Without for a moment admitting that a river is the proper place for the disposal of sewage, even in its most harmless state, "~ it cannot be denied that when it is not contaminated by manufacturing refuse, and when it is discharged in a fresh state into a sufficient volume of water, it is less hurtful to the fisheries than many forms of pollution which receive less attention at the hands of sanitarians and others who are interested in river purification. But ' t o w n sewage' is generally more or less mixed with refuse from manu~There the argument is used--as it commonlyis--that to pour sewage into a river cannot be hurtful, trot rather an advantage, to the fisheries because the finest fish are often found feediDgat the mouths of drains, it is forgotten that this only occurs where the sewage is fresh and the quantity small compared with the volume of water in the stream and the nmnber of fishcontainedin it ; whereas town sewage in most cases reaches a river, not only in large quantities, but in a more or less advanced state of fermentation. The fresher the sewage when it enters a river the Iurther away from the outfall must its deleteriouseftects he sought in the abstraction of oxygen from the water, and in the development of the well-knownsewage fungus, and otherwise.
OF
RIVERS.
307
factories which are allowed to drain into the sewers. I n some cases this refuse matter possesses properties which, if it were mixed with sewage in due proportions and under proper conditions, would serve as a precipitant and deodorant ; in others, manufacturing refuse contains so large a percentage of highly fertilizing matter that its addition to ordinary sewage would largely increase the value of the latter for irrigation purposes : but in many instances these extraneous matters are such as not only to make the discharge of" sewage" into the rivers more undesirable than ever, but to render it totally unfit to be applied to the land ir~ any form. A curious incidence of the added danger which ' sewage ' may contain when turned into a river is afforded by the report of the T y n e Board of Conservators, who state that a "most serious i n j u r y ' was caused to the fisheries in the tidal basin of that river ' b y the Corporation of Newcastle having "disinfected" Byker Burn with caustic soda as one chief ingredient. A smal~ flood took place at the end of July when the river was exceptionally low and the tides not high, the result being that this poisonous material was carried into the Tyne, and . . . every kind of fish for eleven miles of the tideway was destroyed. So poisonous was the ingredient that the fishermen's nets were tainted.' This case is further interesting as illustrating a defect in the Rivers. Pollution Act, which, so tar as I am aware, has escaped observation, but which would at once come into prominence if any general attempt were made to put that Act into active operation. While the Act professes to prohibit the discharge of any sewage matter ' or other ' polluting l i q u i d ' into a stream, it permits--subject to certain provisoes, which have been found practically worthless, as to the adoption of the ' best practicable and reasonably available m e a n s ' for rendering harmless the polluting matter - - the continued discharge of such matter or liquid if the channel by which it is carried was 'used, constructed, or in process of construction ' at the date of the passing of the Act. The sewage or other polluting liquid may have been comparatively harmless, both in quality and quantity, at that time, whereas, since then it may have multiplied many times in volume and virulence. I n other words, however much a town may have increased its population, however many new factories may pour their refuse into the drains, the sanitary authorities are practically held innocent of doing more harm than they did before i876 , provided they turn their 'sewage' into the river through the old exit; or a manufacturer who was doing no practical harm in I876 may ruin a river with impunity in i888 if he uses the original channels for the discharge of the same kind of refuse ; or a dozen manufacturers, who would each be liable to the prohibitions contained in the Act if they constructed new outlets for their refuse, may pollute the river without fear of any real inter•
.
.
SoY
THE
PI!EVENTiON
ference if they make common use of a drain that happened to be in use by one of them in x876. " T h e severaI forms of pollution from mines and factories differ in quality and quantity in different rivers, and the effects of the various matters contained in them are very diverse. Although it is ~suaI so to speak of fish killed by polluted water as having been ' poisoned,' it is a question whether that expression is always strictly correct. That fish are poisoned in the common meaning of the word by the action of irritants taken into the stomach is probably a very rare occurence ; it is possibly hardly tess seldom that they are killed by the absorption of poison into the blood. This is probably the case where arsenic is present in the water, the poison being absorbed and carried into the system with the oxygen. The more frequent cases in which fish can be said to be "poisoned' are those in which an effect analogous to ' skin poisoning' is produced by the action of caustic liquors on the delicate branchiae. Even in such cases the ultimate cause of death is suffocation, owing to the derangement of the functions of the breathing organs. I n all other instances fish are directly suffocated either through the gills becoming clogged by the deposit on them of matters in suspension in the water, or by the water being itself deprived of oxygen by matters either in suspension or in solution in it. An instance of suffocation of fish in the manner last mentioned may be found in the ease of rivers rendered ochreous by the decomposition of iron pyrites. The pollution of rivers by china clay affords a typical illustration of simple suffocation of fish by the mechanical clogging of the gills ; while in the effect of caustic soda may be seen the joint effects of ' poisoning' and suffoca~tion. " B u t not less serious than the actual destruction o f fish is the injury caused to the spawning beds and eggs by the gradual deposit of the matters held in suspension in the liquids discharged from sewers, mines, and manufactories, and by the solid refuse cast either directly into the streams or so close to the banks as to be liable to be washed away by floods; while the destruction of weeds and of insects and other life forming the food of fish is a further aggravation of the evil. "Year after year Boards of Conservators complain o f the inadequacy of the powers conferred upon them, or, indeed, upon any other authority, to prevent these evils. Referring to tbe fact that proceedings under the Rivers Pollution Act can only be taken by sanitary authorities, the Trent Board .ask for ' some cheap and expeditious mode of compelling authorities (called sanitary) and others to desist from polluting streams.' The Pollution Act is ' utterly unworkable and useless ' say the Board of Conservators of the Rhymney Fishery District in reply to the inquiry whether they have taken steps during the past year to prevent pollutions ; the Usk Board similarly represent that ' an altera-
OF
~.~Tore ~.......i x-~t .oxo.
tion in the law which would facilitate prosecutions for pollution is much needed, the existing law being practically useless and unworkable ;' while the Tyne Board declare the Act to be a ' failure.' This opinion is but the echo of the view entertained by Boards of Conservators throughout the country, after twelve years' experience ot the working of that Act. In many cases the polluted state of the rivers is the only impediment, or at least the most serious impediment, to the deveIopment of the fisheries." THE
PREVENTION
OF
PHTHISIS.
By J. EDWARD SQUIRE, M.D.Lond., M.R.C.P., Physician to the North London Consumption Hospital. (Read on Jamta~'y 9NG 1889, before t~e E~idemiolagic~l
Society. )
PHTHISIS is shown, by the annual returns of the Registrar-General, to be one of the most frequent causes of death in this country, more especially during the working period of life, viz., between the ages of x 5 and 6 5 years. If, then, it can be shown to depend upon conditions which are under human cov,trol, it is obviously to the interest of the community that a systematic attempt should be made to diminish, and where possible remove, the preventible causes of this disease. In the present paper, facts are brought together which prove the influence on the prevalence of phthisis of conditions which come within the scope of preventive medicine, and tend to show that much of the mortality from this disease might be prevented by due attention to hygiene and sanitation. Experiments have abundantly proved that tubercular disease can be communicated from affected animals to the healthy ; the communicability of consumption has long been a matter of popular belief, and cases are referred to which seem to prove this point. The dependence of tuberculosis upon the infective bacillus has also been shown by numerous experiments. Phthisis, then, depends primarily upon the reception into the body of an infective particle or micro-organism--the bacillus tuberculosis--and is thus in close relation with the infectious diseases, towards the control of which preventive medicine has already done so much. Amongst the various modes by which the infecting bacillus has been shown to enter the body, there are two which are of special importance in connection with the subject of this paper. Communication by means of the mucous membrane of the alimentary canal is of interest, because of the prevalence of tuberculosis in cattle, and from the experimental proof of the infectivehess of the milk of tuberculous cows. As animals which are crowded together in sheds with deficient ventilation are most liable to tuberculosis, an efficient inspection of cattle kept for dairy purposes is necessary. Although the injurious properties of the milk of diseased animals may be destroyed by