On the epidemiology of the plague / by E. H. Hankin.

  • Ernest Hanbury Hankin
Date:
1905
Catalogue details

Licence: Public Domain Mark

Credit: On the epidemiology of the plague / by E. H. Hankin. Source: Wellcome Collection.

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    was due to rats, while at a later period its spread was due to some other agency. Precisely similar facts were noticed during the outbreak in the town of Bombay, though owing to concealment of cases the statistics are less reliable than in the case of Jawalapur. Existing figures however show that at the commencement of the outbreak the grain dealers furnished more cases than the members of all other trades dealing with other provisions than grain taken together. Later, in November and December of 1896, they showed no such preponderating susceptibility. Migration of rats. It may be replied that the phenomena observed are simply due to an emigration of infected rats. At the commencement of the outbreak they lived in grain dealers’ houses. Later they migrated carrying the infection to other houses. In the case of Bombay there is no doubt that such migration occurred. Further, in nearly every district of the town the plague assumed epidemic form at an interval varying from two to six weeks after the first observed death of rats. But it is not clear why the migrating rats did not carry the infection especially to grain dealers’ shops in other quarters of the town. Neither does the suggested relation apply to numerous other outbreaks in the Bombay Presidency where no special liability of grain dealers was observed. No quantitative relation between rat and human mortality. Yet another line of argument may be brought to bear on the subject. If two phenomena are causally related, we may expect that a variation in one should be followed by a variation in the other. ‘To apply this rule to the matter under discussion, if the disease among rats was the cause of the disease among men that followed it, in so many instances at least, in Bombay, one would expect that where more rats died more men would be attacked, and vice versd. The case of the grain dealers in Mandvie (the first district of the town attacked) may be cited as a strony argument of this kind. But this was only the case at the commencement of the outbreak. During October in Mandvie rats died in other places than in grain dealers’ shops. Children amused themselves by throwing the dead rats out of the windows, and I recollect during this month seeing heaps of dead rats that were about to be destroyed in the streets. No such sight was to be seen
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