302 ON THE FOOD OF ANIMALS. 



rarily take the place of reptiles, in the reduction of temperature, and abstain from all aliments 

 during the greater part of the winter months. The waste and disintegration of the animal sys- 

 tem goes on under all circumstances, but not equally • it is apparently rapid in a severe disease, 

 as is evident in many cases, as the emaciation is excessive, even though of a short contiuance. 



One of the most striking effects of waste is the fall of the leaf in autumn : it may, at least, 

 be regarded as a modified result of decay, and is to the vegetable what the constant waste is 

 to the animal ; it is a periodical waste, while in animals it is constant. Vegetables are not, 

 then, strictly speaking, exceptions to the law of waste and loss of certain tissues, but the whole 

 loss is sustained at once, though this is modified by climate. The systems which are subjected 

 to the greatest waste are the muscular and nervous systems In animals, and the exhalent system 

 in vegetables ; and it is to supply them with renovating matter, that food is required at such 

 short intervals in the former class of beings. Exercise rapidly deteriorates the muscular energy 

 and the integrity of muscular fibre. Mental exercise wastes the nervous matter, and tempo- 

 rarily weakens the intellectual force. Decay is a consequent of activity. The capillaries are 

 active, both in removing and destroying, and thus life internal, like the outward life, is but a 

 contest, a struggle between opposing forces. When the forces are balanced the man is in his 

 vigor. When the renovating force exceeds the disorganizing, growth is the result — it is the 

 child stretching its arms to manhood ; when the latter is predominant, the climax of strength 

 and vigor is past, and age is marked upon the subject by emaciation, leanness of visage and a 

 tottering step. The muscular system labors to maintain its elasticity, the upright form and 

 noble carriage : but the nerves, the messengers of the will, faintly respond to its mandates, and 

 transmit theiB but feebly and cautiously, as if fearful the dilapidated frame would sink under 

 a vigorous effort. In these last stages, that most striking result is the absence of the combus- 

 tible material ; the fatty combustion has more than kept pace with the supply of fuel. The 

 oxidation of the solids, or their combustion, is one of the greatest sources of waste. A large 

 stock of materials is required for the sole purpose of maintaining the temperature of the higher 

 grades of animals above the surrounding medium. Let the aliment for the oxygen become 

 consumed and it attacks the solids of a higher grade, at the expense of finally sacrificing the 

 fabric, so essential is it that the heat should be kept up. It is like the fire of a dwelling, when 

 it has consumed its proper fuel, seizes upon timbers, and wastes the strength of its frame-work, 

 till it falls under its own weight. 



Another fact is well established, and this, too, has an important application to the feeding of 

 domestic animals, viz., that food is required to meet an excessive drain upon the system, as the 

 suppuration of a large abscess, or the secretion of a fluid, as milk. The supply of milk re- 

 quired to sustain the young exhausts the parent, who requires, in her turn, to receive a larger 

 allowance to meet these larger demands upon her system. The system manifests its want of 

 nutriment through the stomach, and the exhaustion of the fluid parts by the fauces. Hunger 

 and thirst are sensations indicative of their respective wantfe, and their calls are too urgent, 

 often, to be disregarded. The powers of life wane more rapidly than they wax, if the individual 

 disregards their calls. The frame is exhausted in a day, but can not recover in three. The 



