1885.] on Cholera : its Cause and Prevention. 303 



Notwitlistancling the overwliclming evidence wliich now exists in 

 proof of the harmlessness of the so-called " rice-water evacuations," 

 it is not the less certain that the mechanism by which the infection 

 of the soil takes place (i. e. by which the disease from being epidemic 

 becomes epichthonic) is its contamination by the discharges of sick 

 persons. For there is no other possible way by which the soil can 

 acquire the morbific property which facts compel us to attribute to 

 it. Similarly, it may be regarded as absolutely certain that the in- 

 fluence of the soil on those who are infected by it is due to the 

 penetration into their bodies of infective material, either by respira- 

 tion or swallowing ; that, in the absence of proof of " cholera-dust," 

 it is a matter of urgent necessity to avoid the use of water which 

 contains such material as from its chemical nature may be reason- 

 ably considered capable of harbouring infective microphytes. 



Id this country and in our Indian possessions experience has led 

 us to do the very things which science, were her opinion asked, 

 would approve as of primary importance. In Calcutta, the 

 measures of sanitary improvement, particularly drainage works, 

 which have been carried out under the highly efiicient sanitary 

 administration there, have during the last dozen years led to a 

 diminution of the cholera mortality to something like a third 

 of its previous average, and similar good results have been obtained 

 elsewhere in India, in so far as it has yet been possible to bring 

 about the necessary reforms. In London we have been lavish 

 m ' our underground expenditure. Our water supply is good and 

 abundant, and our subsoil is dry, so that dwellers in the west and 

 north need not feel much apprehension even though cholera were 

 again to fix itself in the east. But we may, I think, venture to 

 anticipate that this year, at least, we shall not be tried. Cholera, had 

 it intended to attack us this season, would already have been on the 

 march. The eastern provinces of Spain are suffering severely, and 

 it can scarcely be hoped that other parts of the Mediterranean will 

 remain exempt ; but Central Europe is free. Hitherto cholera has 

 come to us from Holland or Germany, not from southern Europe, so 

 that until the Ehine, the Elbe, the Oder, or the Vistula are threat- 

 ened we need be in no immediate apprehension as to the Thames or 

 the Mersey. But in venturing on this favourable forecast, I would 

 beg the reader to understand that I speak with no authority, and 

 recognise his competence to judge as well as I can of its value. 

 Neither science nor experience affords a key to the reasons why 

 cholera now follows one course, now another, in its wanderings over 

 the world. 



I J. B. S.] 



