Page:Popular Science Monthly Volume 20.djvu/265

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253
DISEASE-GERMS.

view to the further experimental testing of the poisonous effect produced upon the grass which will grow over their graves. But the result, says the reporter of the "Times" (June 2d), "is already certain; and the agricultural public now know that an infallible preventive exists against the charbon-poison, which is neither costly nor difficult, as a single man can inoculate a thousand sheep in a day." I have since learned that this protection is being eagerly sought by the French owners of flocks and herds; and, if any severe epidemic of the same kind were to break out in this country, our own agriculturists would probably show themselves quite ready to avail themselves of it. To the "wool-sorters" of Bradford it must prove a most important boon, if they can be led to understand its value.

That this is not to remain an isolated fact, but will be the first of a series of discoveries of surpassing importance (some of them already approaching maturity), is shown by the fact that Pasteur has found himself able to impart a like protection against fowl-cholera by "vaccinating" chickens with its cultivated bacillus.

These wonderful results obviously hold out an almost sure hope of preventing the ravages, not merely of the destructive animal plagues that show themselves from time to time among us, but of doing that for some of the most fatal forms of human infectious disease which Jennerian vaccination has already done—as shown by Sir Thomas Watson in these pages—for what was once the most dreaded of them—small-pox. It is unfortunately too true that, with the reduction of small-pox mortality, there has been an increase in the mortality from measles and scarlatina exceeding that which increase of population would account for, the number of deaths in England and Wales from the former of these diseases frequently exceeding 10,000 in the year, while the annual mortality from the latter averages nearly 20,000, sometimes exceeding 30,000. It scarcely seems too much to expect that before long, as Professor Lister last year suggested, "an appropriate 'vaccine' may be discovered for measles, scarlet fever, and other acute specific diseases in the human subject"; for already, as I have been informed by one of the most distinguished of the United States members of our Congress, researches have been there made, with very promising results, on the "cultivation" of the diphtheritic virus—the mortality from which, in England and Wales, during the last decade, has averaged nearly 3,000 annually, being, for the seven years, 1873-'79, half as great again as the mortality from small-pox during the same period.

Another important line of inquiry, which was supposed by many able pathologists to have been closed by the negative results of previous investigations, has now to be reopened under the new light shed upon it by Pasteur's discoveries: I refer to the relation between cowpox and small-pox. It is well known that Jenner himself, struck with the fact that the protective influence of successful vaccination against