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A point in statistics
CORRESPONDENCE. CHOLERA AND ITS EFFECTS IN S 1 C I L Y . - - T h e B r i t i s h C o n s u l at P a l e r m o in his last report, observes that business during last year suffered g r e a t l y f r o m a n e p i d e m i c o f c h o l e r a in Sicily, t h e m o r t a l i t y b e i n g v e r y g r e a t in m o s t o f t h e t o w n s . T h e p o p u l a t i o n o f P a l e r m o l i v e d for s o m e m o n t h s in a state of "savage panic." T h e effects w e r e heightened by the ignorance and superstitious character of the people generally. In the poorer q u a r t e r s it w a s b e l i e v e d , as in t h e M i d d l e A g e s , that the Government and the richer classes were d i s s e m i n a t o r s o f t h e c h o l e r a p o i s o n , in o r d e r to exterminate the poorer population. Sisters of c h a r i t y w e r e s t o n e d i n t h e i r v i s i t s to t h e h o u s e s o f choleraic patients, and even doctors were sometimes obliged to visit the sick under military escort. A m a n with a d e c e n t c o a t o n h i s b a c k a l w a y s w a l k e d i n d a n g e r o f b e i n g a s s a u l t e d , s i n c e it w a s b e l i e v e d t h a t all w e r e a g e n t s i n a c o n s p i r a c y for the extirpation of the poor. In towns in the interior, tragic scenes ensued in consequence of this superstition. " T h e p o p u l a r m i n d in Sicily s e e m s i n a c c e s s i b l e to a n y i d e a o f t h e v i r t u e o f c l e a n water and soap," and sanitation has been so completely n e g l e c t e d t h a t it m a y b e d o u b t e d w h e t h e r cholera has not become endemic. For a time Messina became a veritable desert; many of the c h i e f m e d i c a l m e n fled, as well a s n u m e r o u s apothecaries ; every house was closed and food was m o s t difficult to p r o c u r e , a n d w h a t w a s o b t a i n a b l e was of the very worst quality. The mortality was a l m o s t e n t i r e l y c o n f i n e d t o t h e h u m b l e r c l a s s e s , all w h o c o u l d l e a v e t h e city h a v i n g fled. CORRESPONDENCE. A
QUINQUENNIAL CENSUS. To t/~e Editor 0fPUBL1C HEALTtL SIR,--Perhaps you will allow me, as one of a class to whom the lack of recent and therefore accurate statistics of population causes especial inconvenience, to enforce Dr. Longstaff's suggestion of a quinquennial census by the following typical example P Nottingham has a population of about a quarter of a million, but the data are insufficient to ensure accuracy e v e n . within such wide limits as Io, ooo or 15,ooo, aud the difficulty will increase year by year until the publication of the results of the 189I census. The official estimate, based upon the censuses of I87I and I88I, is not in harmony with the results o f an enumeration of the inhabited houses last year, or with the other indirect evidence attainable. The growth of the town has been intermfttent, being largely dependent upon immigration during times of commercial prosperity, and any assumption of present uniformity of increase, at a rate determined by observations of such remote date as seven and 17 years ago, is of small practical utility. W e know that Nottingham grew comparatively slowly until about 1878, very rapidly from 1878 to I883, and that since 1884 the immigration from other districts has almost ceased, owiog to long depression of the staple trades of the town. H a d there been a census in 1886 as well as in I88I the estimate for 1888 would be far more trustworthy, owing to the greater proximity of both the requisite fixed points. Under the present eir camstances the uncertainty as to population is so great that the accepted death-rate may be, and probably is, nearly I o per thousand in excess of the truth. A more frequent enumeration wottld be of signal service in another way. I
191
have occasion, not infrequently, to determine the death-rate of special areas within the borough, and to do this it is necessaryto know their populations with approximateaccuracy. One such area to which my attention has recently bce~x directed had in 1881 6oo inhabitants. W h a t its present population m a y be is unknown, but it canuot be less than 2,ooo. As matters stand, the uncertainty upon such a fundamental point as the population renders the preparation of elaborate periodical returns a somewhat disheartening t a s k . - - i remain, Sir, your obedient servant, • A R T H U R W H I T E L E G G E , M.D. .Municipal Offices, Nottingham. A P O I N T IN S T A T I S T I C S . To f~e Edidor of Pum.IC HEA'rm SfR,--A recent discussion in the Times on death-raL~.~ tenrpts me to give the solution of asimple problem not found in any work on statistics. To take the example--given the death-rate of troops at home and abroad (11"12 per I,OOO) and the death-rate of troops at home (6'68 per I,ooo) how is the death-rate of troops abroad calculated ? Let ~zper thousand of the troops be at home ; (IO0O--~z) per thousand of the troops are abroad, x - - deathrate of troops abroad. T h e n out of a thousand soldiers
~z
IOOO
at home, and lOOO--~ X x die abroad.
X 6'68 die
But t I ' 1 2 d%
I000
altogether. Hence ~ ~ - X 6"68 + I O00
Icg--°--n X x = I i ' i 2 . I OOO
x-
IlI2O--n
(6"68)
1000--~/
If the troops are equally divided at home and abroad then ~ is 5oo per thousand this makes sc = 15-56. T h e expression " rate per thousand " at first seems irrespective of the actual proportion of numbers at home and abroad, this is o;course a lallacy. This problem also applies to combined districts, sexes or nationalties, and may be thought worthy of notice. It would make a Rood catch question for ex arnlners.--Your obedient servant, J. H I C K M A N . Sheerness, ITth Sept., 1888. 7b t/~e Editor of PUBLIC HEALTH. S I R , - - I shall feel obliged if you will favour me with your views on the following question : - - T h e Braintree Urban District, population 5,I82, for which I am Health Officer, has a water supply from an artesian well. T h e water is pumped into a low pressure iron tank, raised trom the ground on brickwork to a height of 25 feet, to facilitate distribution, the size of the tank being 3 ° fee~by 3° feet, by 6 feet deep. This tank has no covering of any kind. I have recommended the Braintree Local Board to provide a suitable roof or cover, to prevent accidental contamination. I also sent for the inspection of the Beard at their last meeting a sample of water collected when the tank was emptied, which was extremely unpleasant in appearanee, being full of vegetable growth, and containing many moving organisms, the opinion held by the Local Board, as reported in the newspapeL being," that it was better as it was." I m a y add that there is a high pressure tank, with a roof, within a few yards of the one in question, but only used on special occasions.--Yours faithfully, C. E. A B B O T T , Medical O/ricer o/'Ztealt/zf o r t~e Brai~zlree R u r a l Dist~ ict. Noel House, Braintree, Essex, Sept. I4th , 1888. [The MedicM Officer of Health, having done his duty in the matter, and reported to the sanitary authority the unsatislactory state of the water supply, is now flee fl'om flxrfller responsibility.--E o.]
QUINQUENNIAL CENSUS. To t/~e Editor 0fPUBL1C HEALTtL SIR,--Perhaps you will allow me, as one of a class to whom the lack of recent and therefore accurate statistics of population causes especial inconvenience, to enforce Dr. Longstaff's suggestion of a quinquennial census by the following typical example P Nottingham has a population of about a quarter of a million, but the data are insufficient to ensure accuracy e v e n . within such wide limits as Io, ooo or 15,ooo, aud the difficulty will increase year by year until the publication of the results of the 189I census. The official estimate, based upon the censuses of I87I and I88I, is not in harmony with the results o f an enumeration of the inhabited houses last year, or with the other indirect evidence attainable. The growth of the town has been intermfttent, being largely dependent upon immigration during times of commercial prosperity, and any assumption of present uniformity of increase, at a rate determined by observations of such remote date as seven and 17 years ago, is of small practical utility. W e know that Nottingham grew comparatively slowly until about 1878, very rapidly from 1878 to I883, and that since 1884 the immigration from other districts has almost ceased, owiog to long depression of the staple trades of the town. H a d there been a census in 1886 as well as in I88I the estimate for 1888 would be far more trustworthy, owing to the greater proximity of both the requisite fixed points. Under the present eir camstances the uncertainty as to population is so great that the accepted death-rate may be, and probably is, nearly I o per thousand in excess of the truth. A more frequent enumeration wottld be of signal service in another way. I
191
have occasion, not infrequently, to determine the death-rate of special areas within the borough, and to do this it is necessaryto know their populations with approximateaccuracy. One such area to which my attention has recently bce~x directed had in 1881 6oo inhabitants. W h a t its present population m a y be is unknown, but it canuot be less than 2,ooo. As matters stand, the uncertainty upon such a fundamental point as the population renders the preparation of elaborate periodical returns a somewhat disheartening t a s k . - - i remain, Sir, your obedient servant, • A R T H U R W H I T E L E G G E , M.D. .Municipal Offices, Nottingham. A P O I N T IN S T A T I S T I C S . To f~e Edidor of Pum.IC HEA'rm SfR,--A recent discussion in the Times on death-raL~.~ tenrpts me to give the solution of asimple problem not found in any work on statistics. To take the example--given the death-rate of troops at home and abroad (11"12 per I,OOO) and the death-rate of troops at home (6'68 per I,ooo) how is the death-rate of troops abroad calculated ? Let ~zper thousand of the troops be at home ; (IO0O--~z) per thousand of the troops are abroad, x - - deathrate of troops abroad. T h e n out of a thousand soldiers
~z
IOOO
at home, and lOOO--~ X x die abroad.
X 6'68 die
But t I ' 1 2 d%
I000
altogether. Hence ~ ~ - X 6"68 + I O00
Icg--°--n X x = I i ' i 2 . I OOO
x-
IlI2O--n
(6"68)
1000--~/
If the troops are equally divided at home and abroad then ~ is 5oo per thousand this makes sc = 15-56. T h e expression " rate per thousand " at first seems irrespective of the actual proportion of numbers at home and abroad, this is o;course a lallacy. This problem also applies to combined districts, sexes or nationalties, and may be thought worthy of notice. It would make a Rood catch question for ex arnlners.--Your obedient servant, J. H I C K M A N . Sheerness, ITth Sept., 1888. 7b t/~e Editor of PUBLIC HEALTH. S I R , - - I shall feel obliged if you will favour me with your views on the following question : - - T h e Braintree Urban District, population 5,I82, for which I am Health Officer, has a water supply from an artesian well. T h e water is pumped into a low pressure iron tank, raised trom the ground on brickwork to a height of 25 feet, to facilitate distribution, the size of the tank being 3 ° fee~by 3° feet, by 6 feet deep. This tank has no covering of any kind. I have recommended the Braintree Local Board to provide a suitable roof or cover, to prevent accidental contamination. I also sent for the inspection of the Beard at their last meeting a sample of water collected when the tank was emptied, which was extremely unpleasant in appearanee, being full of vegetable growth, and containing many moving organisms, the opinion held by the Local Board, as reported in the newspapeL being," that it was better as it was." I m a y add that there is a high pressure tank, with a roof, within a few yards of the one in question, but only used on special occasions.--Yours faithfully, C. E. A B B O T T , Medical O/ricer o/'Ztealt/zf o r t~e Brai~zlree R u r a l Dist~ ict. Noel House, Braintree, Essex, Sept. I4th , 1888. [The MedicM Officer of Health, having done his duty in the matter, and reported to the sanitary authority the unsatislactory state of the water supply, is now flee fl'om flxrfller responsibility.--E o.]