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TEE POPULAR SCIENCE MONTHLY 



conditions, the only variation being in the age at which the change sets 

 in. In spite of the unsatisfactory data from which most of these tables 

 were derived, we may infer that the expectation of life at the higher 

 ages has been lessened over a wide area of the country during the last 

 three decades. 



This conclusion is confirmed in a measure by a survey of the mor- 

 tality rates at the several age periods of adult life in the registration 

 states for the years 1900 and 1911, respectively. In order to make our 

 comparison valid, we have been careful to consider only the states which 

 comprised the registration area in 1900. You will note (Table I.) 

 that all age groups up to and including 35 to 44 for males, and 45 to 54 

 for females show decreases in the rates for 1911 as against those for 

 1900. From this age period onward, however, the rates for 1911 are 

 higher than for the earlier date. It is evident that at all ages the mor- 

 tality is much more favorable for females than for males ; but in both 

 sexes the forces that have been at work to reduce mortality in early life 

 have not continued in effectiveness. After the period of middle life, 

 an apparent deterioration has occurred. 



What then are the factors in this change ? From the records of the 

 Bureau of the Census for the registration area it would appear that the 

 causes of death which predominate at the advanced ages, namely, cancer, 

 diabetes, apoplexy, organic heart disease, diseases of the arteries, cir- 

 rhosis of the liver and Bright's disease have increased in their incidence 

 during the last ten years. This is shown in the accompanying Table II. 

 It is significant that, together, these seven causes account for more 

 than one half of the deaths after the age of forty. 



Table I 



Comparison of Mortality of Males and Females by Age Groups. 

 Death-Eates per 1,000 Population 



(Eegistration States as constituted in 1900) 



