Germs, dust, and disease : two chapters in our life history / by Andrew Smart.

  • Smart, Andrew.
Date:
[1883]
Catalogue details

Licence: Public Domain Mark

Credit: Germs, dust, and disease : two chapters in our life history / by Andrew Smart. Source: Wellcome Collection.

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    washed with water contaminated with sewage; or, perhaps, a little of that element has been added to improve its quality!—then fol- lows what is significantly called “ the trail of the millc-man ”—a trail marked by fever cases in perhaps every house to which the milk has been distributed. Or there is a fever at one of our town dairies, in the back-room of the shop, for example, and the attendant on the sick also attends to the customers, who carry the milk to their homes, and with it the germs of future disease. This diagram will assist you to realise more vividly what I have just said. It represents a farm-house in which typhoid fever has arisen, by the milk becom- ing tainted in the way I have spoken of. This dot marks the first case which arose in consequence. Observe how the disease spreads from this starting-point. This other dot shows the second case, which arose in nineteen days from the first, and this, the third, in twenty-six days from the first —all in the same house; but in fourteen days from the first case, a group of three cases occurred in a family, supplied with milk from this farm, and within eight weeks from the first case, a hun- dred and sixty-six persons were laid down with the fever. Look now at this diagram, illustrating the growth of an epi- demic of scarlet fever, from a single case. It is a moderate estimate of the rate of progression of this fever, to say that each case produces two others. Follow these dots from the starting case, and in seven weeks from its commence- ment, you will see that the one case has multiplied into two hun- dred and fifty-six. Once more, study with me this diagram marked cholera. I have said that this disease is propagated by water, fouled by choleraic discharges. Estimating that each case produces five others, a ratio which may be taken as considerably under its usual rate of progression, there would arise six hundred and twenty-five cases within eight days. Several instances of this actually occurred during the cholera epidemic of 1866. The presence of an epidemic of small-pox in London, and the certainty of its early advent amongst ourselves, lead me to
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