DISEASES OF DOMESTIC ANIMALS. Y 



from the sea must have a regular supply of salt, which is an ingredient 

 of the blood, The matters of the blood are liable to changes to a certain 

 extent. The amount of blood is about one-eighth to one-tenth the 

 weight of the animal ; but a much less amount than that, drawn, will 

 produce death. There is depletion of the blood in old animals ; if drawn 

 it is not so readily regained as in young animals. The colour varies be- 

 tween arterial and venous blood ; in the arteries it is a bright red colour, 

 and is lit for the building up of tissues. The blood is carried to the lungs, 

 and carbonic acid passes from it, and it is turned from a dark colour to a 

 light red by absorbing oxygen. After being drawn for a short time it re- 

 solves into two parts the clot, or crassamentum, and the serum. This is 

 the natural result, and does not show inflammation. The serum is almost 

 colourless. We give chloride of potash in purpura, for if fibrine is not 

 present then the blood will exude, and chloride of potash assists coagula- 

 tion A solution of soda wall prevent coagulation. This gives us a clue 

 to the treatment of disease by exerting a certain influence on the blood. 

 Blood kept at a low temperature will not coagulate so readily as if 

 warmer. Heating blood coagulates it, from the albumen it con- 

 tains. Blood receives matter from three sources, from digestion in 

 the alimentary canal, from tissues which have served their purpose, 

 and from the atmosphere through the lungs. Oxygen acts upon 

 the system to a great extent. It is said to act on the various tis- 

 sues when the body dies, destroying all the tissues except the 

 bones ; although such body is not molested by dogs or other ani- 

 mals, and either left upon the ground, or buried, some of the materials 

 go into the ground, others into the atmosphere, etc., and pass from one 

 to another ; and some man at the present day may have some of the 

 identical brain of Julius Caesar. 



Recapitulation of Blood. — The tibrine of the blood is destroyed and 

 reproduced three times in twenty-four hours. So fibrine is a very im- 

 portant substance, for by it we are enabled to control hemorrhage. If 

 rupture of a blood vessel takes place and there is a lack of fibrine or its 

 constituents, it is very hard to arrest hemorrhage ; but if a small vessel 

 is ruptured and the constituents of fibrine are present, you can easily 

 arrest the flow by pressure, for a coagulum is formed and you have heal- 

 ing by the first intention. The fibrine may be increased or decreased 

 under certain circumstances. In laminitis we use soda, for there is an 

 increase of fibrine. If you bleed a horse from the jugular vein, and allow 

 the blood to flow freely into a can, after it settles in the can there is a 

 peculiar white coat upon the surface, which is called buft'. In the horse 

 it is no evidence of inflammatory action, but it is due to the manner in 

 which the blood coagulates ; the white corpuscles being on the top, the 

 red lower down. And the depression on the top of the blood is not due 

 to any change in the condition of the blood. I think you cannot tell by 

 looking at blood what is the matter with the animal. However, in lung 

 disease, the blood is darker than usual, owing to the congested state of 

 the lungs. 



INFLAMMATION. 



Inflammation may be said to be an alteration in the healthy structure 

 of function of a part, accompanied by a perverted condition of the blood 

 in the capillaries, all of which may be due to a certain amount of para- 

 lysi.s of the vital principle of the tissues inflamed. From the earliest 



