498 SOCIAL LIFE OF ANIMALS 



Pulse Frequency 



That there is a quite definite correlation between longevity 

 and rate of pulse beat was strikingly manifested to the writer on 

 comparing his tables with the records furnished in Clark's studies 

 on the physiology of the heart.^ The rodents with a life span of 

 from 5 to lo years range in pulse frequency from 2oo to 520 pulse 

 beats a minute. On the other hand the cat, known to live 23 years, 

 has a pulse rate averaging about 200, while the dog, with a life span 

 of 30 years, has a pulse rate of from 105 to 125 per minute. In birds 

 the canary and the goldfinch, with a longevity of about 20 years, 

 prove to have a pulse rate of about 1,000 per minute, but ducks and 

 geese, with a longevity of 30 to 50 years, have a pulse beat of but 

 150 to 300. In the cold-blooded animals, the pulse rate is much 

 reduced, but a correlation exists as seen in the crocodile which is 

 said to live 100 years, and which has a pulse rate of from 22 to 47 a 

 minute. 



Reading this section in galley proof, O. C. Glaser stated that such 

 a relationship appears to be in harmony with the results obtained 

 by himself (1931) on the relation between heart beat and age in 

 fishes, birds, and mammals. 



^ Clark, A. J. 1927. Comparative Physiology of the Heart. Macmillan Co., 

 N. Y. 



