282 DICTIONARY OF THE VETERINARY ART. 



sometimes happens, though very rarely, — the contents of the 

 stomach will be discharged through the nostrils ; but if the 

 horse happens to cough during the process, some part will be 

 discharged by the mouth. 



Vagina. The passage from the external pudendum, or 

 shape, to the mouth of the womb. 



Valerian. The root of valerian is used as an antispasmodic ; 

 its virtues have been underrated by writers on veterinary 

 medicine. 



Veins. The motion of the heart is known to communicate 

 momentum to the blood through the veins. Mr. Percival 

 says, " We are not to reject the power of the heart altogether, 

 merely because the blood flows with a uniform stream in 

 the veins ; for the absence of pulsation in them is no proof 

 that the motion of the blood is not influenced by the contrac- 

 tions of the heart ; the extreme division which this fluid 

 undergoes in its circulation through the capillaries, and the 

 tortuosity and complication of the numberless small veins, 

 account for the regular and uninterrupted stream which we 

 meet with in the larger branches. To prove that this is the 

 explanation of the fact, if you open a vein that has free and 

 direct communication with the extremity of an artery, (its 

 capillary structure,) the blood will flow from it with the same 

 pulsatory motion, as if the artery itself had been penetrated; 

 but if the vein be one of large size, remotely situated from 

 any arterial communication, or if it be one that springs from 

 the union of numerous capillaries, that smooth and even 

 stream, with which the blood circulates in the trunks, will be 

 observable here. These facts, then, lead us to conclude that 

 the force of the heart is not sufficient of itself to propel blood 

 through the venous system. 



Froni the collected accounts of writers on this subject, it 

 seems highly probable, that the blood flowing in the veins 

 receives additional momentum from the reaction of the 



