26 ALIMENTATION. 



fatal termination does not present any considerable variation. 

 The minimum loss of weight is never at the commencement, 

 but generally at the middle of an experiment. 1 The same 

 observer noted that the proportionate loss of weight was 

 remarkably uniform, even in different classes of animals. 

 In experiments made upon birds, Guinea-pigs, and rab- 

 bits, the almost uniform result was death when the loss 

 reached had four-tenths of the original weight. 2 This rule 

 is somewhat modified by obesity, under this condition the 

 loss of fat beyond the usual quantity being added to the 

 ordinary loss of four-tenths. In a few instances .the pro- 

 portionate loss was increased so as to amount to five-tenths 

 of the weight, but this appeared to be the limit. By refer- 

 ence to the table, 3 it is seen that the two pigeons which the 

 author specially alludes to as very fat, and in which the loss 

 was over five-tenths of the weight, lived respectively lO^oV 

 and 20 T Vo- days ; the average duration of life in the animals 

 of this class being a little more than ten days. This would 

 indicate that, other things being equal, obesity gives a some- 

 w T hat increased power of resistance to inanition. 



Age seems to have a more marked and important influ- 

 ence upon the power of resistance to inanition and the pro- 

 portionate loss of weight before death occurs, than any other 

 circumstance. In a number of experiments upon turtle- 

 doves, in which they were divided into three classes : 1, the 

 young ; 2, those of medium age ; and 3, the adult, the 

 following results were obtained : 



In the first class, death took place in Sy^- days, after a 

 proportionate loss of weight of $ ; in the second, death oc- 

 cured in ByW days, after a proportionate loss of T 3 o^- ; and 



1 CROSS AT, op. dt., p. 16. 



2 In the observations of Chossat on some of the cold-blooded animals (rep- 

 tiles and fishes), it was found that though life continued for a very long period 

 an average of 226 days death occurred when the loss of weight had reached 

 the point at which it takes place in warm-blooded animals. (Op. dt., p. 46.) 



3 Op. dt., p. 12. 



