DIET OF ANIMALS. 201 



with a distended alimentary canal before again called upon by the 

 demands of hunger. The domestic animals will sometimes kill them- 

 selves by overeating when food is continually placed before them, but 

 that is only when they are from their surrounding circumstances relieved 

 from traveling for food and water ; where their time is not, therefore, 

 largely occupied in exercise and in watching for disturbing causes. So, 

 if treated artificially, animals should be managed according to their 

 habits. The collection of food further varies in our different domestic 

 animals : one bolts flesh and coarsely-ground bones, to be deposited in a 

 capacious stomach ; another rapidly swallows large volumes of food and 

 lodges it for awhile in a crop or paunch, to be again regurgitated and 

 masticated at leisure. The fowl crushes its food beyond the crop or 

 stomach in the gizzard. The ox swallows large volumes of food which 

 have been subjected to scarcely any mastication, to return them at leisure 

 to the mouth to be remasticated. The horse collects and at once 

 thoroughly grinds and mixes food with saliva, and rapidly passes it from 

 its stomach to its intestines without the functions of rumination. Habit, 

 therefore, materially influences the collection of food, its retention, and 

 appropriation to the wants of the animal, and is itself governed by the 

 type of the organization of the digestive tract (Gamgee). 



On the basis of the above considerations we may indicate in a general 

 wa} r the fundamental principles which must underlie a rational system of 

 feeding. In the first place, it is evident that the daily ration must be 

 appropriate to the normal mode of feeding and digestive peculiarities of 

 the species ; further, the digestive power in different animals varies not 

 only in different species for the same food, but it varies in different indi- 

 viduals of the same species of different ages. The capacity of the 

 stomach must be considered, that the appetite may be satisfied without 

 the stomach being overloaded. Experiment has proved that the solipedes 

 should receive daily 2 per cent, of their body weight in solids, and rumi- 

 nants 2J per cent, of their weight. 



In the second place, the food must be adjusted with special reference 

 to the demands which are made upon the animal economy, whether for 

 work, fat, or milk production. Special directions for so adjusting the 

 rations will be given after the composition of the food-stuffs and the 

 nutritive changes occurring in different animals in various conditions 

 have been considered. It may be here mentioned, however, that good 

 hay is taken as the type of a food for the larger herbivora, and that it 

 shows a nutritive proportion of one part of nitrogenous matter to 4.8 

 parts of non-nitrogenous constituents, cellulose being disregarded. This 

 proportion, therefore, represents the normal relation between the nitroge- 

 nous and non-nitrogenous matters in the natural diet of the herbivora ; 

 and although this proportion under certain circumstances may be widened 



