Page:Popular Science Monthly Volume 26.djvu/707

in 1,000, in the poor classes it is 72 in 1,000; or at a rate in the former case of ten per cent, and in the latter of seven per cent. Now, curious as it may seem, cancer is met with in the lower animals; and it has been said to prevail more frequently among those which are flesh-eaters than those which are herb-eaters. It has been stated by the late Dr. Crisp, who had good opportunities of judging, that cancer is by no means an uncommon disease among the domesticated animals, while in wild animals and uncivilized man it is rare. In 230 also of the •quadrumana which he had examined there were no traces of cancer. Thus the inference to be drawn from these statements appears to be plain. It is almost conclusive that the habits of life, either in man or the lower animals, are concerned in the production, or at least in the predisposition, to cancer. The surroundings, it is conceivable, of an autochthonic existence do not include influences which favor the production of the disease; consequently, in uncivilized man the disease is rare. It is, however, different when man becomes civilized, for then the predisposing, if not exciting, causes come into play, and man has entered an area of life in which the disease has acquired not only a pronounced but an augmenting fatality. And the same is true of animals. Now, as far as we know at present, cancer has not a zymotic origin; in other words, it does not arise from any microorganism or "germ." It is consequently neither infectious nor contagious. Cancer, in short, can neither be "caught" nor "given." It commences de novo in each individual whom it attacks. There is, moreover, no such thing as anything cancerous being transmitted from parent to child in the cases in which the disease occurs in one and the other. It is possible to inherit a predisposition to cancer—that is, if cancer appears in a family, the members may be said to possess a liability to the disease, but practically this statement does not convey with it much significance, because, until the disease becomes manifest, no person can be said to be cancerous, inasmuch as he does not inherit the disease, but simply the liability to it. We are confronted with the problem of how to limit the frequency of the disease, and the difficulty of this is apparent in view of the fact that we know almost nothing of its origin. Cancer, as I have said, is not contagious; it stands almost alone as a disease which increases with our prosperity, and, while our health laws are raising the standard of public health, the mortality from cancer stands forth as a blot upon the results, detracting in part at least from the measure of the success that has thus far been obtained. Observation has shown that cancer has a certain geographical distribution. It prevails extensively in some parts of the globe, and is scarcely known in others. For instance, it is met with most largely in the central parts of Europe, but in the extreme north of this continent the inhabitants enjoy an almost complete immunity from cancer. It is stated to be unknown in the Faroe Islands, while in Iceland in one year it proved mortal in only thirty-seven cases out of 50,000 inhabit-