24:0 



COMPARATIVE PHYSIOLOGY. 



Now, if with these terms there arise ia the mind correspond- 

 ing mental pictures of the action of the heart under the cir- 

 cumstances, well ; if not, there is a very undesirable blank. 

 How the student may be helped to a knowledge of the actual 

 behavior of the heart under a variety of conditions we shall 

 endeavor to explain later. 



Apart froin aU the above peculiarities, the heart may cease 

 its action at regular intervals, or at interval* which seem to 

 possess no definite relations to each other — ^that is, the heart 

 may be irregular in its action, which may be made evident 

 either to the hand or the ear. 



There are certain deviations from the quicker rhythm which 

 occur with such regularity and are so dependent on events that 

 take place in other parts of the body that they may be con- 

 sidered normal. 



Comparative. — We strongly recommend the student to verify 

 all the statements made in these sections by direct observation 

 for himself. Such is invaluable to the practitioner. The fol- 

 lowing table gives the mean number of cardiac pulsations per 

 minute (after Gamgee) : 



SPECIES. 



Horse 



Ass and mule. . 

 Ox 



Sheep and goat 



Pig 



Dog 



Cat 



Adult. 



36- 40 

 46- 50 

 45- 50 

 70- 80 

 70- 80 

 90-100 

 130-140 



Youth. 



60- 73 



65- 75 



60- 70 



85- 95 



100-110 



110-120 



130-140 



Old age. 



33- 88 

 55- 60 

 40- 45 

 55- 60 

 55- 60 

 60- 70 

 100-120 



The variations with age, for the horse and the ox, are as fol- 

 lows, according to Kreutzer : 



Morse. 



At birth 100-120 



When 14 days old 80-96 



When 3 months old 68- 76 



. When 6 months old 64^ 72 



When 1 year old 48-56 



When 3 years old 40-48 



When 3 years old 38-48 



When 4 years old 38-50 



Whenaged 32-40 



Ox. 



At birth 93-133 



When 4-5 days old 100-120 



When 14 days old 68 



When 4-6 weeks old 64 



When 6-12 months old . . 56- 68 



For the young cow 46 



For the four-year-old ox . 40 



