106 BIOLOGY OF DEATH 



they are. Space is lacking here to go into the details, 

 and I must consequently ask the reader either to take it 

 on faith for the time being that the classification is at 

 least a fairly reasonable one, or to take the trouble to 

 go over it in detail in the original publication.* 



GENERAL RESULTS OF BIOLOGICALLY CLASSIFIED DEATH BATES 



Here I should like to present first some general statis- 

 tical results of this classification. The data which we 

 shall first discuss are in the form of death rates, from 

 various causes, per hundred thousand living at all 

 ages, arranged by organ systems primarily concerned 

 in death from specified diseases. The statistics came 

 from three widely separated localities and times, vis., 



(a) from the Registration Area of the United States; 



(b) from England and "Wales ; and (o) from the City of 

 Sao Paulo, Brazil. 



The summarized results are shown in Table 7, and in 

 graphic form in Figure 26. 



The rates are arranged in descending order of magni- 

 tude for the United States Registration Area, with the 

 exception of those of group X, all other causes of death. 

 We note in passing that this biologically unclassifiable 

 group includes roughly 10 to 15 per cent of the total 

 mortality. It may be well to digress a moment to con- 

 sider why these deaths cannot be put into our general 

 scheme. Table 8 exhibits the rates included in class X. 



This residue comprises in general three categories 

 (a) accidental and homicidal deaths; (b) senility; and 



* Cf. particularly Pearl, R. " On the embryological basis of human 

 mortality." (Proc. Natl. Acad. Sci. Vol. 5, pp. 593-598, 1919) and "Cer- 

 tain evolutionary aspects of human mortality rates." (Amer. Natl. Vol. 

 LIV. pp. 5-44, 1920). The following section as well as Chapter V are 

 largely based upon the second of the two papers. 



