84 DISEASES OF CATTLE. 



The extractives are different elements in such small proportions as to 

 require special means to extract them. Fibrin does not exist in the 

 living blood as fibrin, but the elements are there, ready to form fibrin 

 under certain circumstances. The internal lining of the blood-vessels 

 appears to prevent the formation of fibrin, but when the blood conies 

 in contact with anything foreign to it, fibrin is quickly formed, and 

 coagulation (or the clot of blood) is the result, unless certain means 

 are used to prevent it. Fibrin is a very important factor in surgery. 

 When a wound is made and blood escapes, fibrin is formed, which 

 'auses the blood to coagulate or clot, and which materially assists in 

 arresting hemorrhages. Carbonic acid gas is carried by the liquor san- 

 guinis, both in solution and combined with the soda. 



The blood is alkaline, due to the salts it contains. Its specific gravity 

 varies from 1.050 to 1.057. The weight of blood in cattle is estimated 

 by a good authority to be 1 pound to every 23 pounds of the weight 

 of the body. 



The lymphatics, or absorbents, are the vessels which carry the lymph 

 and chyle into the blood. Like the veins, they have three coats or 

 tunics, but much thinner. They begin as capillaries in all parts of the 

 body, and they have valves. Placed along the course of the lymphatic 

 vessels are glands, and in some situations these glands are collected 

 into groups; for example, in the groin, etc. These glands are often 

 involved in inflammation arising from the absorption of deleterious 

 matter. For instance, a sore may be on a finger, and the lymphatic 

 capillaries there may absorb a poisonous or irritable matter, which is 

 carried by the lymphatic vessels to the collection of lymphatic glands 

 in the armpit, and inflammation of the glands results and gives rise to 

 the familiar waxing kernel. 



Absorption is the function of the lymphatics. The liquor sanguinis 

 passes from the blood capillaries to supply nutrition to the tissues. All 

 excess of the liquor sanguiuis that is not required is absorbed by the 

 lymphatic capillaries and conveyed back to the blood by the lymphatic 

 vessels. The lymphatics which proceed from the intestines convey the 

 chyle into the blood during digestion. Tfce lymph (fluid carried by 

 these vessels) is composed of white corpuscles, albumen, salts, water, 

 extractives, and the elements of fibrin. In fact, it is blood without the 

 red corpuscles. Chyle consists of the same constituents as lymph, with 

 the addition of fatty matters. As a rule, the lymphatic vessels follow 

 the course of the veins. All of the absorbent vessels convey their con- 

 tents to the thoracic duct and right great lymphatic vein, which empty 

 into the anterior vena cava, where the lymph and chyle mix with the 

 venous blood, and thus maintain the supply of nutritive elements in 



the blood. 







PULSE. 



As fully explained, the heart pumps the blood throughout the arte- 

 rial system. The arteries are always full and overfull, and each con- 



