22 General Principles of Veterinary Medicine. 



nearly every disease on the catalogue. Improper food, and 

 too little or too much exercise bring on indigestion or dys- 

 pepsia, in which complaint there may be one or another form 

 of disturbance. Colic, gripes or hoven is an accumulation of 

 air or gas in the stomach or bowels, painfully stretching their 

 walls. Scouring is a too free and watery action of the intes- 

 tines ; dysentery and enteritis are when the intestines are in- 

 flamed ; and obstruction occurs when through hair-balls, 

 rupture or twistings their passage is choked up. 



THE HEART, BLOOD-VESSELS ATST) ABSORBEJ^^TS. 



The digested food, we have seen above, is taken up in the 

 intestines in the shape of a milky fluid by innumerable absor- 

 bent points or villi. What do they do with it ? They pour 

 it into the absorbent vessels or lymphatics, which empty into 

 larger and larger ones, and so on until the whole of the nu- 

 tritive fluid is collected into one great duct or tube, which 

 extends forward and pours its life-giving contents into the 

 large veins at the base of the neck, whence it is conveyed to 

 the heart and enters the general circulation of the blood. 



And this circulation, what is meant by it? It means 

 that the blood is drawn in and driven out of the heart by 

 its powerful throbs, with such force and rapidity that the 

 whole of it in the body makes the circuit of the system in 

 less than three minutes, washing out the dead and worn out 

 particles, discharging them by the lungs, kidney and liver, 

 and purging and brightening itself in the fresh air drawn 

 in by the lungs for another such rapid and purifying race. 



The parts concerned in this circulation are the heart, the 

 arteries and the veins. The arteries lead /rom the heart; the 

 blood they carry is bright red, and it flows in waves, felt on 

 the pulse, and shown when an arteiy is cut by the blood 

 spouting in jets or spurts. The veins lead to the heart : the 



