74 THEORY OF FEEDING. 



somewhat resembling that of the dung of goats. Also, from 

 undue retention, the residue of the food which is in the' 

 intestines is liable to become decomposed, with the result that 

 the animal's health suffers more or less from the absorption of 

 deleterious products. The bad effect of diarrhoea has already 

 been discussed. 



It is interesting to note that the condition of the dung is 

 by no means uniform in all animals. Thus, as compared to 

 horses, dogs are in a constant state of constipation ; and 

 horned cattle, in one of diarrhoea. 



TAKING FOOD INTO THE MOUTH. 



The first act in the digestion of food is its prehension 

 (seizure), which is accomplished by the lips and afterwards 

 by the front teeth (incisors = cutters). If the grass, hay, 

 or other food offers resistance to its removal on being 

 caught hold of by the lips, the front teeth will help to 

 detach it by their cutting action, and the upper lip, which 

 is gifted with great mobility, a high degree of sensitiveness, 

 and a fair amount of muscular strength, will be capable 

 of more or less encircling it and of exerting traction on 

 it. The knowledge that the upper lip is very sensitive 

 to pain teaches us that an ordinary twitch should be used 

 only in cases in which the infliction of pain is justified 

 by necessity. Also, the employment of this twitch has the 

 great disadvantage, from a pecuniary point of view, that it 

 is liable to depreciate the animal's value by rendering him 

 difficult to be handled about the head, as for instance, in 

 bridling him. When the food has been detached and is held 

 by the lips, the teeth become separated from each other, and 

 the tongue, aided by the lips, conveys the food to the back of 

 the mouth. Colin has shown by experiment, that a horse is 

 unable to take any solid food into his mouth without the aid 

 of his lips. In cattle, the tongue performs the office of the 



