HUMAN LONGEVITY 



69 



The material falls into three categories, as follows: non-users 

 of tobacco, of whom there were 2094; moderate smokers y of 

 whom there were 2814; and heavy smokers y of whom there 



Fig. 



so 60 70 SO 



yfG£ /A/ Yky^/fS 



12. The survivorship lines of life tables for white males falling" into three 



categories relative to the usage of tobacco. A. Non-users (solid line) ; B. Moderate 

 smokers (dash line) ; C. Heavy smokers (dot line) . 



were 1905. In other words, the results presented here are based 

 upon the observation of 6813 men in total. Naturally these men 

 were an unselected lot except as to their tobacco habits. That 

 is to say they were taken at random, and then all sorted into 

 categories relative to tobacco usage. For each of the three cate- 



