482 PHYSIOLOGY AT THE FARM. 



cal process or of a course of nutrition in a living animal, may 

 be rendered more and more uniform, in every respective case, 

 by more and more pains being bestowed to bring all the cir- 

 cumstances concerned therein to a degree of perfection. But the 

 occasion wherein inert matter alone is under trial will much 

 more certainly repay the pains expended by affording a corre- 

 sponding uniformity of result, than that in which living action 

 is the subject of experiment. The reason whereof is, that it is 

 commonly easy to bring any given number of inert machines 

 or of manipulations on inert matter to an almost perfect simi- 

 larity; whereas no pains can bring two individuals endowed 

 with life to act exactly in the same manner, even under an 

 identity of circumstances. Every animal has an individual 

 character, involving peculiarities which affect all its actions, 

 nutritive as well as relative. Whence an approximation only 

 can be made to certainty in the results expected from any rule 

 of treatment, however "well established, even in animals not 

 merely of the same species, but of the same variety in that 

 species, and bred as nearly as possible in the same manner. 



This tendency to peculiarities of character in individual 

 animals enables us to understand why, in trying any new plan 

 of management, however well it may promise, there is not 

 certainty of success, if no more than one or two animals are 

 subjected to it, and in particular, before any such plan can be 

 pronounced a failure, that the result must be ascertained in 

 respect to a considerable number of the animals concerned; 

 again, why there is room for pretty large variations, even in 

 plans of management proved to be of good general effect in 

 their application to individual animals, such as what is rightly 

 called skill alone can devise and put in practice. 



In the earlier parts of this treatise it has been pointed out, 

 as far as the present state of knowledge therein permits, how 

 exact the agreement is between the constituent elements of 



