Page:Popular Science Monthly Volume 89.djvu/887

 Popular Science Mntitlihj

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��in the six left-hand cylinders. The same mo\ement ol the lc\er also closes a biitterlly- valve in the left intake-mani- fold as shown in the illustrations, so that no gas reaches the six left cylinders. All the re- ciprocating parts of the latter continue to oper- ate regularly except that there is no compression or explosions, due to the fact that the exhaust valves are open and no gas can reach the c\linders. I'nder these conditions the motor oper- ates as a six-c>Iinder type except that it has to carry the slight addilional load of reciprocating the mo\ing parts of the cut-out cylinders.

���With the Ifft six cylinders cut out all the other parts operate as usual except that the exhaust valves remain wide open

��CAMS CAM-SHAFT SUPPOflTS

��The Cancer Problem and How

Modern Science Is

Attacking It

THE man in the street generally thinks of cancer as a hopelessly incurable disease which has attacked many of his friends and relatives and, like death itself, is too unpleasant to talk about. It rarely occurs to him that he may be the next \irtim, nor does he realize that if he is o\er fort\- years old there is one chance in fourteen that he will die of this disease, and as regards his wife, if of equal age, one chance in only eight. Vet if he stopped to consider what these figures mean he would perhaps decide that an ostrich policy of hiding from the unpleasant facts of life is in this case, as always, a serious mistake. Not, however, that he should lie awake nights worrying about the matter. An accurate idea of the frefjuency of cancer should merely stimulate a person of healthy intelligence to learn liow to avoid the disease and how to prevent a fatal result if, in spite of all precautions, it should afflict him or a member of his family. Starting out on such an inquiry he would soon find that he was right in thinking cancer a common disease but wrong in believing it to be an unavoidable and incurable ailment.

Cancer is indeed more common than most people realize. In 1914 there were 54,420 deaths from all forms of cancer in

���At the rear end of a camshaft a ball-and-socket joint connects with a shaft that leads to the operating lever

the United States Registration Area, which comprises about 60*^0 of the population of the country. If the same rate of fatality prevailed in the states and cities outside the Registration Area. o\-er 80,000 persons in the continental United States must have succumbed to this malignant disease durinj, that year. In his recentU' published book "The Mortality from Cancer Throughout the World," Frederick L. Holifman esti- mates that during the ten years ending with 1913 there were 658,139 deaths from cancer in the United States, and that the total of deaths from this disease in all civilized coimtries is not less than 500,000 anniialh-.

F"rom the annual reports of the Census Bureau, it is seen that cancer ranks fifth among the leading causes of death at all ages and that only tuberculosis, heart diseases, pneumonia, and kidney diseases take a greater toll of life. Considering only deaths that occur after thirty years of age, cancer presents an even more serious aspect. It is indeed primarih" a disease of adult life, the average of death being 59 years as contpared with 36 in the case of tubercu- losis. In the Inited States Registration Area 83*^ of all deaths from cancer, during the years 1906-iqio inclusi\-e, occurred at ages of fort\--five and over.

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