22 Feeds and Feeding. 



38. The biood. — Blood is the circulating medium of the body, 

 bearing in its current both the elements of nutrition and waste. 

 The composition of the blood of a horse is given as follows: 



100 Parts Venous Blood. 



Corpuscles 32.62 



Plasma 67.38 



100 Parts Plasma. 



Solids 9.16 



Water 90.84 



Fibrin 1.01 



Albumen 7.76 



Fats 0.12 



Extractives 0.40 



Soluble salts 0.64 



Insoluble salts 0.17 



The blood of the horse has been estimated at one-eighteenth 

 the weight of the body. Colin places the blood of the ox at one 

 twenty-third the body weight. Numerous attempts have been 

 made to ascertain the time required for the blood to make a com- 

 plete circuit of the body. Vierordt places the period of circula- 

 tion for the horse at 31.5 seconds. In the case of the ox it is 

 estimated that three pints of blood are driven through the left 

 ventricle of the heart at each beat, and, since there are about 

 fifty beats per miuute, the circulation must be very rapid. The 

 surging movement of the blood through the artery constitutes 

 the pulse, and each movement marks a beat of the heart. The 

 frequency of the pulse in our domestic animals has been placed 

 as follows: Beats 



per minute. 



In the horse 36 — 40 



In the ox 45 — 50 



In the pig 70 — 80 



In the sheep 70 80 



The frequency of the pulse varies greatly yftih age, as shown by 

 the following table: 



Heart heats per minute. 



Horse. Ox. 



Newborn 100 — 120 92 — 132 



One-fourth year old 68 — 76 



One year old 48— 56 50— 68 



Four years of age 38— 60 56 — 



^ged 32— 40 46— 50 



