July 7, 1916] 



SCIENCE 



31 



prise the population and deaths of the nine 

 registration states of that year: Connecticut, 

 Delaware, Massachusetts, New Hampshire, 

 New Jersey, New York, Ehode Island, Ver- 

 mont, and the District of Columbia. The 

 statistics of the years 1900 and 1910 which 

 were used in this investigation comprise those 

 of the same states enumerated above, except 

 Delaware, and of the states Indiana, Maine 

 and Michigan. 



The mortality tables were completed at the 

 extreme and relatively unimportant ages not 

 covered by reliable data, in the rather arbi- 

 trary manner discussed by Mr. King. 



The abridged mortality tables are given here 

 for visual comparison, but our discussion will 

 be directed solely to the death rates and ex- 

 pectations of life given later. 



MORTALITY TABLES 



It is to be noticed that the ages in the 

 neighborhood of the age of birth are ignored. 

 This is practically necessary in the use of such 

 short methods, considering the great varia- 

 tions in death rates at the ages of this period. 

 However, examination of various mortality 

 tables constructed upon mortality conditions 

 in the United States will reveal little differ- 

 ence between the expectation of life at age 

 twelve and that at the age of birth. Thus, 



the expectation of life at age twelve is a fair 

 estimate of the average length of the whole of 

 American life, especially when used for pur- 

 poses of comparison of two or more sets of 

 mortality conditions. 



The abridged list of death rates and corre- 

 sponding differences are as follows: 



DEATH RATES PER 100,000 



Females 



In the table of death rates given above, at- 

 tention is called not so much to the absolute 

 values and their differences — for the results 

 lack graduation — but rather to the trend of 

 mortality conditions as indicated by them. 

 This trend among both the males and females 

 is unquestionably forward at all ages below 

 60, except in the decade 1900-1910, in which 

 the advance among the males is terminated at 



