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DOMESTIC WATER PIPES
1156
VITAMIN A AND INFECTION.—DOMESTIC WATER PIPES
infections were milder, yielded the same answer. HESS concludes that " there is no clinical basis for considering or designating vitamin A the antiinfective vitamin." The other investigation recorded was made by Dr. ROBERT recently SUTHERLAND,3 in the winter of 1931-32, at the North School, Peterhead, which is frequented by very poor children. One group of 281 children received two Radiostoleum capsules daily, while another group of 294 got control capsules of arachis oil. SUTHERLANDS study is very elaborate and includes observations of a great number of points in connexion with health by which the true comparability of the two groups was carefully established. But although the children receiving radiostoleum did show a slight superiority in growth, he sums up by saying: "No definite evidence of diminished susceptibility to infection or of increased resistance to established disease has been found in the radiostoleum group considered
whole." These two
as a
inquiries, with others equally leave little doubt that the incidence illness amongst the ordinary child Great Britain or the United States cannot be lowered by prophylactic treatment with vitamin A ; for this class of disease vitamin A is certainly not an anti-infective vitamin. And on reflection one is able to see that the hope was likely to be vain, for a comparison was being made between two states which were not truly analogous. The rat, when it develops infections due to vitamin-A insufficiency, is already very definitely depleted of vitamin A, though not completely so, and its eyes can easily be seen to be abnormal. The Peterhead on the other is not in such a hand, school-child, of the one earliest signs condition ; night blindness, of vitamin-A deficiency, is certainly not common. When, however, a child really is depleted of vitamin A, as in C. E. BLOCH’s famous series of cases, reported in 1921, it is intensely susceptible 0. to infection, and readily succumbs to it. BLEGVAD (1924), for instance, mentions that in children suffering from keratomalacia, the cause of death is nearly always broncho-pneumonia ; in a series of 60 cases of keratomalacia, 46 died from this cause, while enteritis, pyelitis, and nephrolithiasis also occurred. These are the infections in man which are truly analogous with those in the A-deficient rat, and it is in these circumstances that, both for man and rat, vitamin A is truly an anti-infective vitamin. When we do find evidence that vitamin-A therapy has influenced the course of infection there is usually a probability that, through disease or some special cause, the body’s reserves of vitamin A had been brought so low that the mucous membranes were damaged and thus made vulnerable. It may well be that women under the drain of pregnancy get near this level ; and Prof. E. MELLANBY, in the Lloyd-Roberts lecture which we publish this week, points out that when a group of 275 pregnant women was treated with vitamin A before delivery their morbidity-rate was lower than disappointing, of respiratory population of
3 Sutherland, R. : M.D. Thesis, Univ. of Aberdeen, 1933.
that of controls-to a statistic ally significant degree. In South Africa, where native mine-workers are
notoriously subject
to
pneumonia, administration
of vitamin A after onset of the disease was not found of any value, but there was at least an indication that the mean vitamin-A reserves in the liver of those dying from pneumonia was lower than in controls dying from accident.4 Indeed, F. W. Fox,5coordinating his own South African figures with those given by L. K. WOLFF and T. MOORE in our columns, believes that by " there is no longer any doubt that persons dying of pneumonia tend to have lower reserves of vitamin in their livers than those who have died from accidental causes." In this connexion, it may be mentioned that the London County Council’s report on measles, reviewed in our issue of Oct. 28th, mentions (p. 91) a series of 300 cases of measles treated with a concentrate of vitamins A and D, in which the total deaths-almost all from pneumonia-numbered only 11, whereas in a control untreated group there were 26. In each of these three instances-puerperal sepsis, pneumonia in native mine-workers, and pneumonia complicating measles-there is a possibility that the vitamin-A reserves of the patient were so depleted, for one reason or another, that the soil was made ready for the seeds of disease to germinate. In this sense and for such cases vitamin A may be the anti-infective vitamin. With common colds and the milder respiratory diseases of infants and young children, however, there is no indication that lack of this accessory factor is an essential part of the preparation of the soil. It may be that here some other factor plays an important part-an insufficiency of iron for instance, as Prof. MELLANBY suggests. But it does now seem regrettably certain that vitamin A does little or nothing to prevent the everyday respiratory
infections.
DOMESTIC WATER PIPES FROM early times water has been distributed from the mains’in pipes made of lead, one of the most poisonous of metals. Its great ductility and the ease with which joints can be soldered specially fit it for the tortuous system needed to carry a supply of water into various parts of a house. As large towns have, in the main, grown up on the banks of rivers whose water contains calcium bicarbonate from the limestone or chalk strata through which it has passed, no ill-effects have as a rule been observed. The state of affairs became very different when some of the northern towns, seeking a purer supply outside their own borders, began to draw on upland sources yielding very soft water. Dr: R. P. WILLIAMS has told the story in a lecture at King’s College, published in our issue of Oct. 28th (p. 990). It is remarkable that distilled water or water containing so little mineral matter as closely to approach it in solid content-moorland water contains about four parts per 100,000should have the power of dissolving lead so rapidly. 4 Orenstein, A. J., and Fox, F. W. : S. African Med. Jour., 1932, 5 Fox, F. W. : THE LANCET, 1933, i., 953.
vi., 685 and 689.
1157
CEREBRAL ANGIOGRAPHY
Distilled water in contact with sheet lead for an hour or less takes up sufficient of the metal as hydroxide to give a strong reaction with chromate ; this is however soon precipitated as carbonate, which is only very sparingly soluble in water but much more soluble in the gastric juice. For solution to occur the water must contain dissolved oxygen or be exposed to the air, whence the carbonic acid which precipitates the lead when dissolved is also derived. Pure lead can be kept without tarnishing under oxygen-free water, but this condition cannot be ensured in waterworks practice. Fortunately, if the water contains appreciable amounts of carbonates, sulphates, or silicates the solution of lead soon ceases. The explanation seems to us something like this :Lead like most other metals is appreciably, although slightly, soluble in water ; witness the oligodynamic action of silver and of copper on bacteria and green growths in water. In the presence of anything, like oxygen, which will form with the ions at the surface a compound more soluble than lead itself, the chemical action goes on until a saturated solution-in this case of lead hydroxide-is formed. If however the water contains ions which will form less soluble lead compounds, the lead ions which tend to leave the surface of the metal remain anchored to it and form a protective coating of carbonate, sulphate, and/or silicate. But this protective action occurs only when the proportion of ions forming these sparingly soluble lead compounds is sufficient to depress the solubility of the lead salts, in accordance with the law of mass action by which the mutual solubility of two ions is determined by their " solubility product." For instance, a completely saturated solution of (say) lead sulphate will, on the addition of an excess of either constituent, yield a precipitate; hence lead sulphate is less soluble in water containing calcium sulphate than it is in distilled water. When a water contains traces of free sulphuric acid, as some peaty waters may do which have been in contact with iron pyrites, lead sulphate is likely to be formed and to go into solution to saturation point, there being only a small excess of sulphate ions to depress the solubility of the lead. very
The most certain way of decreasing the solvent action of water on lead is to neutralise any mineral or organic acids in it by passing it over limestone or chalk, which will dissolve in amounts sufficient to ensure the formation of a protective coating The addition of flint pebbles to on the pipes. provide a little silicate further decreases the possibility of a dangerous amount of lead getting into the water. The amounts dissolved are in any case of course very small, but one part of lead in two millions of water is dangerous-in fact, any detectable amount should be considered as too much, since lead is only very slowly eliminated from the body. Prof. L. S. P. DAVIDSON, with his collaborators, has recently described in our columns1 an outbreak of lead poisoning in the north-east of Scotland, which was investigated by him and a group of colleagues. The facts are disturbing. Supplies of water, presumably mostly from private sources, were conveyed to houses by long lengths of lead piping, and the lead content of the water first run off after the pipes had stood full for a time was 1
THE LANCET,
August 12th, p. 374.
the many cases of lead the inhabitants. poisoning among Having regard to the almost general use of-lead for water pipes it seems incumbent on public water authorities to render their supplies incapable of dissolving lead. If this cannot be done other materials must be used for the pipes. Prof. DAVIDSON suggests the replacement of lead pipes by iron. This might give rise to the need for frequent renewal and complaints of chalybeate tastes in the water. Galvanised pipes yield zinc to some waters, and although not very poisonous zinc salts have an unpleasant flavour. Lead pipes coated internally with tin are available. But tin is the most expensive of the base metals and although well-coated tin-lined pipes would be absolutely satisfactorytinned vessels have long been used for many years for culinary purposes-if the coating is not continuous the danger is still present, for, if tin and lead are left in contact in a plumbosolvent water, lead rapidly goes into solution. Copper pipes are satisfactory, but have the drawback of being more difficult to install than the easily bent and soldered lead ; copper is the noblest of the base metals and the small traces of copper which might go into solution would, as HOUSTON pointed out, have no harmful effect on water drinkers. Copper is in fact an essential constituent of the tis3ues. Another alternative is the new triple alloy of lead, tin, and cadmium, recently commended by the Non-Ferrous Metals Research Association, which seems to yield rather less lead to water than does lead itself. Its use has been sanctioned in Manchester, but it should not be forgotten that cadmium is a very poisonous metal. Private users of soft water would, it seems, be well advised to incur the rather heavy initial expense of copper
sufficient to
or
well-tinned
explain
piping.
CEREBRAL ANGIOGRAPHY IT is
five years since Prof. MoNiz, of Lisbon, began study the radiological appearances of the cerebral blood-vessels after injection of opaque solutions into the carotid artery.I On another page will be found illustrations of normal and abnormal positions of vessels revealed in typical cases, with the conclusions which Mo-Niz’s extensive experience has enabled him to draw from their inspection. His studies have revealed important new anatomical and physiological facts. The radiothe internal show that carotid grams artery within the skull curves in a manner more complicated than has been hitherto described by anatomists. It is likely that the single or double curve, which MoNiz calls the carotid syphon, plays a considerable part in ensuring a steady non-pulsating stream of arterial blood within the cranium. By taking a series of radiograms at intervals of one second, it has been found possible to display the cerebral veins and sinuses as well as arteries, and MONIZ has therefore changed the name of the procedure from arteriography to angiography. He has also been able to show that the blood circulates much faster now
to
within the brain than in its 1 See THE
coverings,
LANCET, 1931, i., 249:
and
and he
ii., 863.
VITAMIN A AND INFECTION.—DOMESTIC WATER PIPES
infections were milder, yielded the same answer. HESS concludes that " there is no clinical basis for considering or designating vitamin A the antiinfective vitamin." The other investigation recorded was made by Dr. ROBERT recently SUTHERLAND,3 in the winter of 1931-32, at the North School, Peterhead, which is frequented by very poor children. One group of 281 children received two Radiostoleum capsules daily, while another group of 294 got control capsules of arachis oil. SUTHERLANDS study is very elaborate and includes observations of a great number of points in connexion with health by which the true comparability of the two groups was carefully established. But although the children receiving radiostoleum did show a slight superiority in growth, he sums up by saying: "No definite evidence of diminished susceptibility to infection or of increased resistance to established disease has been found in the radiostoleum group considered
whole." These two
as a
inquiries, with others equally leave little doubt that the incidence illness amongst the ordinary child Great Britain or the United States cannot be lowered by prophylactic treatment with vitamin A ; for this class of disease vitamin A is certainly not an anti-infective vitamin. And on reflection one is able to see that the hope was likely to be vain, for a comparison was being made between two states which were not truly analogous. The rat, when it develops infections due to vitamin-A insufficiency, is already very definitely depleted of vitamin A, though not completely so, and its eyes can easily be seen to be abnormal. The Peterhead on the other is not in such a hand, school-child, of the one earliest signs condition ; night blindness, of vitamin-A deficiency, is certainly not common. When, however, a child really is depleted of vitamin A, as in C. E. BLOCH’s famous series of cases, reported in 1921, it is intensely susceptible 0. to infection, and readily succumbs to it. BLEGVAD (1924), for instance, mentions that in children suffering from keratomalacia, the cause of death is nearly always broncho-pneumonia ; in a series of 60 cases of keratomalacia, 46 died from this cause, while enteritis, pyelitis, and nephrolithiasis also occurred. These are the infections in man which are truly analogous with those in the A-deficient rat, and it is in these circumstances that, both for man and rat, vitamin A is truly an anti-infective vitamin. When we do find evidence that vitamin-A therapy has influenced the course of infection there is usually a probability that, through disease or some special cause, the body’s reserves of vitamin A had been brought so low that the mucous membranes were damaged and thus made vulnerable. It may well be that women under the drain of pregnancy get near this level ; and Prof. E. MELLANBY, in the Lloyd-Roberts lecture which we publish this week, points out that when a group of 275 pregnant women was treated with vitamin A before delivery their morbidity-rate was lower than disappointing, of respiratory population of
3 Sutherland, R. : M.D. Thesis, Univ. of Aberdeen, 1933.
that of controls-to a statistic ally significant degree. In South Africa, where native mine-workers are
notoriously subject
to
pneumonia, administration
of vitamin A after onset of the disease was not found of any value, but there was at least an indication that the mean vitamin-A reserves in the liver of those dying from pneumonia was lower than in controls dying from accident.4 Indeed, F. W. Fox,5coordinating his own South African figures with those given by L. K. WOLFF and T. MOORE in our columns, believes that by " there is no longer any doubt that persons dying of pneumonia tend to have lower reserves of vitamin in their livers than those who have died from accidental causes." In this connexion, it may be mentioned that the London County Council’s report on measles, reviewed in our issue of Oct. 28th, mentions (p. 91) a series of 300 cases of measles treated with a concentrate of vitamins A and D, in which the total deaths-almost all from pneumonia-numbered only 11, whereas in a control untreated group there were 26. In each of these three instances-puerperal sepsis, pneumonia in native mine-workers, and pneumonia complicating measles-there is a possibility that the vitamin-A reserves of the patient were so depleted, for one reason or another, that the soil was made ready for the seeds of disease to germinate. In this sense and for such cases vitamin A may be the anti-infective vitamin. With common colds and the milder respiratory diseases of infants and young children, however, there is no indication that lack of this accessory factor is an essential part of the preparation of the soil. It may be that here some other factor plays an important part-an insufficiency of iron for instance, as Prof. MELLANBY suggests. But it does now seem regrettably certain that vitamin A does little or nothing to prevent the everyday respiratory
infections.
DOMESTIC WATER PIPES FROM early times water has been distributed from the mains’in pipes made of lead, one of the most poisonous of metals. Its great ductility and the ease with which joints can be soldered specially fit it for the tortuous system needed to carry a supply of water into various parts of a house. As large towns have, in the main, grown up on the banks of rivers whose water contains calcium bicarbonate from the limestone or chalk strata through which it has passed, no ill-effects have as a rule been observed. The state of affairs became very different when some of the northern towns, seeking a purer supply outside their own borders, began to draw on upland sources yielding very soft water. Dr: R. P. WILLIAMS has told the story in a lecture at King’s College, published in our issue of Oct. 28th (p. 990). It is remarkable that distilled water or water containing so little mineral matter as closely to approach it in solid content-moorland water contains about four parts per 100,000should have the power of dissolving lead so rapidly. 4 Orenstein, A. J., and Fox, F. W. : S. African Med. Jour., 1932, 5 Fox, F. W. : THE LANCET, 1933, i., 953.
vi., 685 and 689.
1157
CEREBRAL ANGIOGRAPHY
Distilled water in contact with sheet lead for an hour or less takes up sufficient of the metal as hydroxide to give a strong reaction with chromate ; this is however soon precipitated as carbonate, which is only very sparingly soluble in water but much more soluble in the gastric juice. For solution to occur the water must contain dissolved oxygen or be exposed to the air, whence the carbonic acid which precipitates the lead when dissolved is also derived. Pure lead can be kept without tarnishing under oxygen-free water, but this condition cannot be ensured in waterworks practice. Fortunately, if the water contains appreciable amounts of carbonates, sulphates, or silicates the solution of lead soon ceases. The explanation seems to us something like this :Lead like most other metals is appreciably, although slightly, soluble in water ; witness the oligodynamic action of silver and of copper on bacteria and green growths in water. In the presence of anything, like oxygen, which will form with the ions at the surface a compound more soluble than lead itself, the chemical action goes on until a saturated solution-in this case of lead hydroxide-is formed. If however the water contains ions which will form less soluble lead compounds, the lead ions which tend to leave the surface of the metal remain anchored to it and form a protective coating of carbonate, sulphate, and/or silicate. But this protective action occurs only when the proportion of ions forming these sparingly soluble lead compounds is sufficient to depress the solubility of the lead salts, in accordance with the law of mass action by which the mutual solubility of two ions is determined by their " solubility product." For instance, a completely saturated solution of (say) lead sulphate will, on the addition of an excess of either constituent, yield a precipitate; hence lead sulphate is less soluble in water containing calcium sulphate than it is in distilled water. When a water contains traces of free sulphuric acid, as some peaty waters may do which have been in contact with iron pyrites, lead sulphate is likely to be formed and to go into solution to saturation point, there being only a small excess of sulphate ions to depress the solubility of the lead. very
The most certain way of decreasing the solvent action of water on lead is to neutralise any mineral or organic acids in it by passing it over limestone or chalk, which will dissolve in amounts sufficient to ensure the formation of a protective coating The addition of flint pebbles to on the pipes. provide a little silicate further decreases the possibility of a dangerous amount of lead getting into the water. The amounts dissolved are in any case of course very small, but one part of lead in two millions of water is dangerous-in fact, any detectable amount should be considered as too much, since lead is only very slowly eliminated from the body. Prof. L. S. P. DAVIDSON, with his collaborators, has recently described in our columns1 an outbreak of lead poisoning in the north-east of Scotland, which was investigated by him and a group of colleagues. The facts are disturbing. Supplies of water, presumably mostly from private sources, were conveyed to houses by long lengths of lead piping, and the lead content of the water first run off after the pipes had stood full for a time was 1
THE LANCET,
August 12th, p. 374.
the many cases of lead the inhabitants. poisoning among Having regard to the almost general use of-lead for water pipes it seems incumbent on public water authorities to render their supplies incapable of dissolving lead. If this cannot be done other materials must be used for the pipes. Prof. DAVIDSON suggests the replacement of lead pipes by iron. This might give rise to the need for frequent renewal and complaints of chalybeate tastes in the water. Galvanised pipes yield zinc to some waters, and although not very poisonous zinc salts have an unpleasant flavour. Lead pipes coated internally with tin are available. But tin is the most expensive of the base metals and although well-coated tin-lined pipes would be absolutely satisfactorytinned vessels have long been used for many years for culinary purposes-if the coating is not continuous the danger is still present, for, if tin and lead are left in contact in a plumbosolvent water, lead rapidly goes into solution. Copper pipes are satisfactory, but have the drawback of being more difficult to install than the easily bent and soldered lead ; copper is the noblest of the base metals and the small traces of copper which might go into solution would, as HOUSTON pointed out, have no harmful effect on water drinkers. Copper is in fact an essential constituent of the tis3ues. Another alternative is the new triple alloy of lead, tin, and cadmium, recently commended by the Non-Ferrous Metals Research Association, which seems to yield rather less lead to water than does lead itself. Its use has been sanctioned in Manchester, but it should not be forgotten that cadmium is a very poisonous metal. Private users of soft water would, it seems, be well advised to incur the rather heavy initial expense of copper
sufficient to
or
well-tinned
explain
piping.
CEREBRAL ANGIOGRAPHY IT is
five years since Prof. MoNiz, of Lisbon, began study the radiological appearances of the cerebral blood-vessels after injection of opaque solutions into the carotid artery.I On another page will be found illustrations of normal and abnormal positions of vessels revealed in typical cases, with the conclusions which Mo-Niz’s extensive experience has enabled him to draw from their inspection. His studies have revealed important new anatomical and physiological facts. The radiothe internal show that carotid grams artery within the skull curves in a manner more complicated than has been hitherto described by anatomists. It is likely that the single or double curve, which MoNiz calls the carotid syphon, plays a considerable part in ensuring a steady non-pulsating stream of arterial blood within the cranium. By taking a series of radiograms at intervals of one second, it has been found possible to display the cerebral veins and sinuses as well as arteries, and MONIZ has therefore changed the name of the procedure from arteriography to angiography. He has also been able to show that the blood circulates much faster now
to
within the brain than in its 1 See THE
coverings,
LANCET, 1931, i., 249:
and
and he
ii., 863.