No. 630] 



HUMAN MORTALITY BATES 



going as a whole functioning mechanism. Naturally it 

 would be expected that the casualties would be far heavier 

 in the first two defense lines (respiratory and alimentary 

 systems, and blood and circulation) than in the home 

 guard. Death rates when biologically classified bear out 

 this expectation. 



4. It is at first thought somewhat surprising that the 

 breakdown of the nervous system is responsible for more 

 deaths than that of the excretory system. When one 

 bears in mind, however, the relative complexity of the 

 two pieces of machinery, it is perceived that the relative 

 position of the two in responsibility for mortality is what 

 might reasonably be expected. 



5. In the United States the kidneys and related excre- 

 tory organs are responsible for more deaths than the sex 

 organs. This relation is reversed in England and Wales 

 and in Sao Paulo. A return to Table III shows that this 

 difference is mainly due, in the case of England, to two 

 factors, premature birth and cancer. In Sao Paulo it is 

 due to premature birth and syphilis. The higher pre- 

 mature birth rate for these two localities as compared 

 with the United States might conceivably be explained in 

 either of two ways. It might mean better obstetrics here 

 than in the other localities, or it might mean that the 

 women of this country as a class are somewhat superior 

 physiologically in the matter of reproduction, when they 

 do reproduce. The first suggestion seems definitely more 

 improbable than the second. The higher apparent syph- 

 ilis rate of Sao Paulo probably means nothing more than 

 better reporting, a less prudish disinclination to report 

 syphilis as a cause of death in Sao Paulo than in the other 

 two countries. It is by no means beyond the bounds of 

 possibility that if all deaths really due to syphilis and 

 gonorrhea were actually reported as such, the rate for 

 the sex organs would be decidedly higher than for the ex- 

 cretory organs in all countries. 



6. The last three organ systems in the table, skeletal 

 and muscular system, skin and endocrinal organs, are 



