DICTIONARY OF THE VETERINARY ART. 269 



Physic. In stable language, the term is applied to purga- 

 tive medicines. 



Physiology. That branch of medical science which de- 

 scribes the functions of every part of the body. 



Pia Mater. A delicate membrane, that closely invests the 

 brain. 



Pitch, Burgundy. A resin obtained from fir ; it is used in 

 the composition of plasters and charges. 



Placenta. The afterbirth. 



Plate Vein. A large vein that runs from the inside of the 

 fore leg to the chest. 



Plethora. A fulness of vessels. Horses are often brought 

 into this state from overfeeding, and want of sufficient exer- 

 cise. It is known by heaviness, dulness, unwillingness to 

 work. The urine is high colored, and the dung generally 

 hard and slimy. The cure consists in the reduction of the 

 quantity of food, warm mashes, and regular exercise. 



Pleura. The membrane which covers the lungs so closely 

 as to appear a part of their substance. 



Pleurisy, Pleuritis. Inflammation of the pleura. 



Plexus. A network of blood-vessels or nerves. 



Pneumonia. A general term for inflammation of the lungs. 



Poisons. Articles which impede or destroy the vital oper- 

 ations. Some people proclaim that all food is poison ; that 

 the difference in the effect produced lies in the quantity given. 

 We deny this : good corn, oats, and hay, whose nature is to 

 nourish and support the animal, can never be a legitimate 

 cause of disease. Its excess in quantity, and its chemical 

 decomposition for want of digestive power, are all of true 

 food that can prove injurious. On the other hand, experience 

 teaches us that opium, arsenic, corrosive sublimate, tobacco, 

 and calomel are inimical to the animal organization, and will 

 never change their chemical equivalents. A grain of arsenic 

 will always be a grain of that poison, and can be detected 

 after death : the same applies to opium. A very few grains 

 of opium injected into the carotid artery of a dog, killed him 

 in four minutes ; when the same quantity was injected into a 



