196 PHYSIOLOGY OF THE DOMESTIC ANIMALS. 



nature in concentrated form, so as not to tax the digestive organs. Thus, 

 for workingmen meat shoulcl represent the accessory rations ; for horses 

 oats is the suitable form. For if the extra food is given to the horse in 

 grasses it becomes impossible to work him because of the overdistension 

 of the alimentary canal necessitated by the greatly increased volume of 

 food required. Again, in fattening animals or in animals kept for milk- 

 ing purposes the diet must be rich, in albumen, in fats and carbo-hydrates. 

 Equivalent values of different amounts of different foods cannot be deter- 

 mined by chemical analysis alone, as will be shown when the nutritive 

 A^alues of the different foods are considered. That two foods should 

 have the same nutritive value they should contain equal proportions of 

 nitrogenous matters, carbo-hydrates, salts, etc., in equal volumes. They 

 should possess equal stimulating properties to the digestive tract, and 

 should be of equal digestibilitj^. It is a general rule that animal matters 

 are more nutritive than vegetable matters, bulk for bulk. They are, 

 further, more varied in composition, and are more readily assimilated. 



The mode of diet suitable for different animals, the character of 

 their food and its nature, varies very widely in different classes of ani- 

 mals, whether carnivorous, herbivorous, or omnivorous. Each of these 

 classes has a special mode of alimentation, as especially emphasized by 

 Colin, which is governed by the characteristics of its digestive organs. 

 In each of these three groups of animals a number of subdivisions may 

 be established. Thus, among the carnivora there are animals which only 

 eat living prey ; others, only decomposing animal matter ; others, again, 

 only insects. 



Among the herbivora, some only eat grasses; others, only grains; 

 others, roots and leaves, etc. The mode of alimentation suitable to each 

 of these species is closely dependent upon the digestive organs of each, 

 and governs its habits, instincts, and characters, and is dependent largely 

 upon the modes which it possesses of attack and defense. 



The carnivora, especially those belonging to the group of mammals, 

 have a strikingly characteristic organization. Their incisor teeth are cut- 

 ting, their canine teeth long and pointed, as are also the cusps of their 

 molar teeth. Their jaws are short ; their masseter and temporal muscles 

 enormously developed, lodged in deep temporal fossae, and attached 

 to highly-curved zygomatic arches ; their oesophagus dilatable ; their 

 stomachs large ; their intestines short and simple, and their caeca small 

 or absent. Their feet are divided and furnished with more or less pointed 

 claws. They are admirably organized for the discovery of their prey by 

 acute sight or acute sense of smell or hearing ; their agility or cunning 

 enables them to surprise and seize their prey, and their strength to tear 

 it to pieces; while their jaws are powerful enough to crush the bones, 

 and their gastric .juices powerful enough to dissolve them. Such animals 



