The aerial convection of small-pox from hospitals / by J. C. McVail.

  • McVail, J.C.
Date:
1894
Catalogue details

Licence: Public Domain Mark

Credit: The aerial convection of small-pox from hospitals / by J. C. McVail. Source: Wellcome Collection.

Provider: This material has been provided by London School of Hygiene & Tropical Medicine Library & Archives Service. The original may be consulted at London School of Hygiene & Tropical Medicine Library & Archives Service.

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    siderable risk oi proving too much, even by his negative evidence. Reviewing, shortly, the main points of this interesting correspondence, we lind :— 1. That Waterhouse started with the opinions: (a) That the small-pox infection depended on variable conditions of virus, of atmosphere, and of subject ; (h) that it was a particulate poison; and (c) that, in regard to the extent of its atmospheric spread, positive evidence was valid, and that negative evidence was to be accounted for by one or more of tlie several variabilities. 2. That Haygarth held : (a) That the infection depended on practically fixed and unchanging conditions, alike as to virus, atmosphere, and subject; (b) that the virus was not particulate, but that at any given distance from its source the poison was equally dissolved throughout the whole atmosphere ; and (c) that, therefore, negative evidence was much more valuable than positive evidence. 3. That Haygarth's pleading led Waterhouse to believe in this superiority of negative evidence, and that the next occurrence of small-pox in Boston furnished him with suffi- cient of such evidence to cause him to yield to Haygarth's views, that the spread of small-pox throughout the atmo- sphei-e was to be measured by a few inches, not by hundreds of feet or yards, and that even in a last-century dwelling- house it could not be carried by the atmosphere through an open door into an adjoining apartment. To me Waterhouse's conversion seems a very high com- pliment to Haygarth's persuasive powers, rather than evidence of the truth of the thesis he sought to establish. In the present day it is not quite impossible that we are just a little in need of being warned by Waterhouse's example to avoid the pitfall into which he tumbled. We are perhaps too apt to forget that the aerial infectivity of small-pox may vary according to the intensity of the virus, the condition of the vehicle by which it is conveyed, and the state of the subject to whom it is conveyed. About a year ago, when there seemed a likelihood of a prevalence of small-pox in Dumbartonshire, one of the points which I had before me as belonging to the teaching that an outbreak might afford, was this question of the aerial dissemination of the disease by hospitals. I therefore took account of the circumstances of one hospital which was likely to be used for Dumbartonshire small-pox, in order to see how its experience might be utilised in this connection.