844 



SCIENCE 



[N. S. A^OL SLIII. No. 1120 



rate continues to decrease until the twelfth 

 year of life — that is, the period between the 

 eleventh and twelfth birthdays — during which 

 it is only 228 per 100,000 for males and 198 

 per 100,000 for females. This, the figures indi- 

 cate, is the healthiest year of life among native 

 whites. Thereafter there is a continuous in- 

 crease in the death rate from year to year. 

 During the forty-eighth year of life, in the 

 case of native white males, it is 1,267 per 100,- 

 000, or almost exactly what it was during the 

 third year, 1,266; during the sixty-second 

 year it is 2,919 per 100,000, or a little more 

 than during the second year, 2,841, and during 

 the eightieth year it is 12,184, or somewhat less 

 than during the first year, 12,602. Similarly, 

 among native white females the rate during 

 the fiftieth year, 1,120, is a little less than dur- 

 ing the third year, 1,144; during the sixty- 

 third year it is 2,548, or somewhat less than 

 during the second, 2,610, and during the 

 eightieth it is 10,901 per 100,000, or a little 

 more than during the first, 10,460. The native 

 white man at the age of 102 and the native 

 white woman at 99 have approximately the 

 same prospect of dying within one month that 

 they had at birth. 



To say that a person's expectation of life is 

 a certain number of years is not the same as 

 saying that he has an even chance of living 

 that number of years. This is because, as al- 

 ready explained, expectation of life represents 

 the average remaining length of life, at any 

 given age, in a stationary population, whereas 

 an average person in a given group has an 

 even chance of living to what is called the 

 median age at death, that is, the age below 

 which half of the members of that group wiU 

 die. The median age at death for all native 

 white males in the assumed stationary popu- 

 lation would be 60; that is to say, sf a given 

 number of such males born alive, half would 

 die before reaching 60 and the other half at 

 60 and beyond. A native white male child at 

 birth, then, has one chance in two of reaching 

 this age. At the end of his first year, how- 

 ever, he has a trifle better than an even chance 

 of reaching 64 ; and at 42 he has one chance in 

 two of attaining three score and ten. Simi- 

 larly, a native white female child at birth has 



an even chance of living a few months past 

 the age of 64; at the age of 1 she has one 

 chance in two of hving until she is nearly 68 

 years old; and at 22 her chance of reaching 

 70 is an even one. Thus a native white man 

 at 42 and a native white woman at 22 have 

 about the same chances of celebrating their 

 seventieth birthdays. 



The relative healthfulness of city and 

 country is strikingly shown by the tables, ac- 

 cording to which the death rate among white 

 males under 1 year of age in cities having 

 8,000 inhabitants and over in 1909, and in 

 cities of 10,000 and over in 1910 and 1911, is 

 13,380 per 100,000 bom alive, whereas in 

 smaller places the corresponding rate is only 

 10,326 per 100,000, or 23 per cent, less than the 

 rate for cities. A similar difference prevails 

 with respect to white females under 1 year of 

 age, for whom the death rate in cities is 11,123 

 per 100,000 born alive, while in rural localities 

 it is only 8,497 per 100,000, or 24 per cent, less 

 than the urban rate. 



For white males the expectation of life, at 

 birth, in rural localities is 7.7 years greater 

 than in cities; at the age of 10, 5.4 years 

 greater, and until the age of 39 is reached 

 there is a margin of more than five years in 

 favor of the country. Thereafter the differ- 

 ence becomes gradually less, but is always in 

 favor of the country ujitil the age of 88 is 

 reached, at and after which the cities show a 

 slightly greater longevity than the rural lo- 

 calities. 



For white females the difference between 

 urban and rural longevity, while pronounced, is 

 somewhat less than in the case of males. At 

 birth the white female's expectation of life is 

 6 years greater in rural than in urban locali- 

 ties; at 10, 3.3 years greater, and until the age 

 of 46 is attained the difference continues to be 

 more than 3 years. Thereafter it declines 

 until the age of 83 is reached, after which the 

 cities have a slight advantage over the country. 



THE IROQUOIS INDIAN GROUPS OF 

 THE NEW YORK STATE MUSEUM 

 There have recently been opened for public 

 exhibition in the New York State Museum six 



