Page:Popular Science Monthly Volume 76.djvu/561

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FEW successful skirmishes in the interminable conflict with disease happened to take place recently on American soil. We saw the weapons of defense which scientific research had forged for us valiantly wielded by some of our countrymen and a new interest in preventive medicine, which has spread far beyond the ranks of the medical profession, was the result. Such discoveries as the detection of the part played by the mosquito in the transmission of yellow fever and by the rat flea in the spread of bubonic plague were interesting enough to gain a place in the news of the day but it was the fact that the first demonstrations of their surpassing practical value were given by medical officers of the American Army and Marine Hospital Service in our own land that gave rise to the present widespread confidence in the achievements possible in the domain of public health. It is natural, perhaps, that this newly awakened interest in the prevention of disease should center in the infectious diseases, in which the relation between cause and effect is often so obvious and the means of prevention are so logical. The school children of New Orleans easily grasped the simple facts in the case against the yellow-fever mosquito and they became efficient recruits in the memorable campaign of 1905. Much of the success in the present general movement against tuberculosis, the most formidable of all our unseen foes, is due to the fact that nearly all we know of its transmission can be reduced to half a dozen maxims, each of which can be expressed in as many words. It would be unfortunate, however, if popular interest in the battles for the public health should not extend to those diseases in which the relation between cause and effect is one step farther removed.

It is essential that the front presented to the common enemy should be as wide as our present knowledge justifies. There need be no fear of disaster from advancing in extended order, for an attack upon one position of the adversary will not infrequently disclose an unsuspected weakness in another. Since May, 1907, every effort has been made by the combined federal and city forces to rid San Francisco of bubonic plague. With victory assured, the results of what has been done are being counted up and it is found that measures undertaken for the extermination of plague have brought about a sanitary