OF VETERINARY MEDICINE. 17 



Fibrin is also decreased in certain diseases. In pregnancy 

 there is a decreased amount of fibrin. Some idiosyncracy may 

 be a factor in causing a lack of fibrin in the blood. The function 

 of fibrin is to prevent hemorrhage ; if it were not for fibrin every 

 animal would bleed to death. 



Anaemic animals are lacking in fibrin; animals starving to 

 death are an exception. The fibrin in their blood is increased. 

 A local blister increases the fibrin in the adjacent tissues. During 

 debilitating diseases as in purpura hemorrhagica, the fibrin is 

 decreased. 



PULSE. 



To define the pulse concisely is difficult ; the various dic- 

 tionaries give a variety of definitions. Probably the American 

 Pocket Dictionary has the best. According to it the pulse is 

 the expansion and contraction of the arteries as the result of the 

 action of the heart. The latter part of the definition is necessary 

 for the vessels are dependent upon the action of the heart. 



Arteries have three coats, the middle one, which consists of 

 non-striated muscle, the inner one, the intima, and the outer one 

 or the adventitia. The muscle is controlled by the vaso-motor 

 system, which maintains the tonicity of the vessels. The vaso- 

 motor system is dependent upon the general condition of the 

 body for its vitality. 



The pulse depends upon the tonicity of the arterial muscles. 



These muscles depend upon the vaso-motor system. 



The vaso-motor system depends upon the general condition. 



A horse might appear to be in apparently good health but 

 if his pulse runs up to 60 or drops a beat now and again, then 

 something is wrong with him. The pulse is the index to the 

 nervous system. 



The Effect of an Acute Inflammatory Disease Upon the 

 Pulse. — In the first stage the nervous system is excited; the 

 pulse is strong, full, regular and increased in frequency a little. 

 In the second stage the nervous system is still more excited, but 

 the pulse is growing weaker. Under such a condition the pulse 

 is rapid, smaller and weaker than normal. In the third stage, 



