Variola ovina, sheep's small pox, or The laws of contagious epidemics illustrated by an experimental type.

  • William Budd
Date:
1863
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Licence: Public Domain Mark

Credit: Variola ovina, sheep's small pox, or The laws of contagious epidemics illustrated by an experimental type. Source: Wellcome Collection.

Provider: This material has been provided by the Harvey Cushing/John Hay Whitney Medical Library at Yale University, through the Medical Heritage Library. The original may be consulted at the Harvey Cushing/John Hay Whitney Medical Library at Yale University.

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    disease of the animal. In both, the common result was the evolution of a disease of incomparably milder type than when taken in the natural way. But the great importance of the phenomena presented by in- oculation consists in the clear light they throw on the nature of the disorder. In the majority of the inocu- lated cases, the variola appeared in the mildest pos- sible form. The eruption was limited to a single vesicle, and constitutional disturbance was slight or altogether absent. In some few, the course of events was otherwise; and the malady, although inoculated, took a malignant ton. One such case I saw. A sheep that had been inoculated some days before—in result, no doubt, of some individual predisposition— threw out a confluent eruption. The animal was at once sacrificed. Had the papulse been allowed to de- velope into vesicles, there would have come from the minute atom of virus inserted by the lancet a few days before, a new crop sufficient to communicate the same disease to all the sheep in Wiltshire.t Here, then, in results free from all ambiguity, and open to the eye, the great fact is revealed, that it is in the body of the sheep that this strange poison is fashioned and multiplied; and that the disease itself is the process by which it is bred. In this one experiment almost everything is comprised. We see, first, how minute a germ is sufficient to produce the disorder; we see, again, how, by reason of this very minuteness, signs of general disturbance are absent until growth has taken place; and, lastly, in the immeasurable multiplication which follows, we understand in what way provision is made for the ex- tension of the disease, until, from a single first case, a whole epidemic is evolved. The spectacle presented to us is, indeed, not new. To the physicians of the last century, as seen in the case of human small-pox, it was sutticiently familiar. But, for some reason or other, we have been sin- gularly slow in applying the lesson it so plainly taught. I may add, that one of the main points of interest in the fact here recorded is, that it repeats in one of the lower animals a series of relations that had already been observed of another and kindred disease in man. + Profes;or Siraonds has recorded several exactly similar in. stances in his work on Variola Ocina.