90 CONTEMPORARY SCIENCE 



This table shows that the influence of temperature on 

 the duration of life of the fly is the same as the influence 

 of temperature on the velocity of a chemical reaction, in- 

 asmuch as a lowering of the temperature by ten degrees 

 results in an increase in the duration of life by two or 

 three hundred per cent., and the same figure would be 

 obtained if we investigated the effect of temperature upon 

 the time required to complete a chemical reaction. At 

 30 C. the flies live on an average 21.15 days and at 

 20 C. they will live on an average 54.3 days or a little 

 over twice as long. At 25 they live 38.5 days and at 

 15 C. 123.9 days or about three times as long. The fruit 

 fly is a tropical organism and 30 C. is not far from the 

 optimal temperature. By lowering their temperature 

 twenty degrees we prolong the duration of their life by 

 nine hundred per cent. We cannot lower the temperature 

 below 10 since the flies suffer in the chrysalid stage when 

 the temperature becomes 10 or less. While these are 

 thus far the only experiments on the duration of life of 

 higher organisms carried out with the necessary scientific 

 precaution, there are many casual observations mentioned 

 in the literature which suggest that lowering the tempera- 

 ture prolongs the duration of life of lower animals in 

 general. 



The body temperature of a normal human being is 

 constant, namely about 37.5 C. and this temperature re- 

 mains the same in the tropics and in the arctic regions. 

 Human beings and most mammals differ in this respect 

 from insects whose temperature is as a rule practically 

 that of their surroundings. If it were possible to reduce 

 the temperature of human beings and if the influence of 

 temperature on the duration of life were the same as 

 that in the fruit fly, a reduction of our temperature from 

 37.5 to about 16 would lengthen the duration of our life 

 to that of Methusaleh ; and if we could keep the tempera- 

 ture of our blood permanently at 7.5 C., our average life 

 would (on the same assumption) be lengthened from 



