Diseases of the Heart and Organs of Circulation. 40/ 



The internal capacity of the ventricles is so modified by 

 the amount of post mortem contraction that it differs widely from' 

 the actual capacity during life. The left ventricle of the larger 

 domestic quadrupeds usually admits from 3^ oz. to over 5 oz., 

 while the right ventricle with walls so much thinner and 

 more lax will contain double that amount. In the smaller ani- 

 mals about a tenth of these quantities will be admitted. 



The weight of the heart, too, can only be stated as an average 

 or for medium sized animals. In the horse it may be from 4}^ lbs. 

 to 9 lbs. ; in the ox from 3 lbs. 5 oz. to 4^ lbs. ; in the sheep 

 from 5^ oz. to 7 oz. ; in the pig from 9)^ oz. to 14 oz. ; and in 

 the dog from 5 oz. to 7 oz. This statement must be understood 

 to apply to dogs approximating in size to the shepherd's. 



Taking into account the size of the particular animal any con- 

 siderable deviation from these measurements and weights, may be 

 accepted as abnormal. The ratio to the body weight is about :— 

 horse and dog i : 100, ox, sheep and pig i : 220. This neces- 

 sarily varies with condition — fat or lean. 



The pulse offers valuable indications in disease of the heart. 



The number of the pulse in healthy full-grown animals may be 

 set down as follows per minute : — horse, 36 to 46 ; ox, 38 to 42 

 (with loaded paunch or in a hot stable up to 70) ; sheep, goat 

 and pig 70 to 80; dog, 80 to 100 ; cat, 120 to 140 ; goose, no ; 

 pigeon, 136 ; chicken, 140. In old age the pulse is less frequent. 

 This diminution may extend to 5 beats per minute in the larger 

 quadrupeds and to 20 or even 30 in the smaller. Youth and 

 small size again are associated with a greater rapidity of the pulse. 

 The pulse of the foal, at birth, is about three times that of the 

 horse ; in the colt of six months it is double ; at a year old about 

 one and a half times ; and at two years old one and a quarter. 



The smaller the animal, caeteris paribus, the more rapid is the 

 pulse. Hot buildings, exertion, fear or any other exciting cause 

 likewise accelerates it. It is more frequent with the nervous 

 temperament, as for example in the English race horse, or the 

 greyhound, than in the dull lymphatic cart-horse, or mastiff. In 

 advanced pregnancy it is increased in number. In the cow and 

 mare it undergoes a monthly increase of four or five beats per 

 minute after the sixth month. (Delafond.) 



Independently of these conditions, a rapid pulse indicates febrile 



