208 BIOLOGY OF DEATH 



richest group. Indeed, the difference between the first three London 

 groups is slight, significant excess only being apparent for the poorest 

 group. And whereas the excess of mortality of the poorest over the 

 richest group in Paris is 104 per cent., in London it is only 30 per cent." 



He theu examines the question as to whether the dis- 

 crepancies may be due to differences in the method of con- 

 struction of the two, sets of mortality figures and concludes : 



"That the remarkable contrast in experience between the two cities 

 cannot be explained, except possibly in a very minor degree, by any 

 differences of method in compilation of the statistics compared." 



Stevenson then goes on to, the discussion of infant 

 mortality and says : 



"The conclusion just arrived at applies still more to infant than to 

 total mortality, for, in its case, the contrast between rich and poor quarters 

 of Paris assumes dimensions which, in the light of London experience, seem 

 quite fantastic." 



Eegarding mortality from tuberculosis the London 

 experience again fails to agree with the Paris experience, 

 and Hersch's conclusions from the data of the latter city 

 would be absurd if applied to the former. 



EXPERIMENTS ON TEMPEEATTJEE AND DURATION OP LIFE 



Altogether it is plain that we need another Mnd of 

 evidence than the simple unanalyzed parallelism which 

 Hersch demonstrates between poverty and the general 

 death rate if we are to get any deep understanding of the 

 influence o;f environmental circumstances upon the dura- 

 tion of life or the general death rate. We shall do well 

 to turn again to the experimental method. About a 

 dozen years ago Loeb, 



starting from the idea that chemical conditions in the organism are one 

 of the main variables in this case, raised the question whether there was a 

 definite coefficient for the duration of life and whether this temperature 

 coefficient was of the order of magnitude of that of a chemical reaction. 

 The first experiments were made on the unfertilized and fertilized eggs 



