Popular Science Mntitlihj 



873 



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 tlie 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 tlie 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. 



