430 Edward Livingston Youmans, 



and inside out, so as to compel a revelation of their 

 secrets : hence, in proportion as the sources of error be- 

 come more numerous and fallacies more insidious, a subt- 

 ler exercise of the reason is demanded — more circumspec- 

 tion in weighing evidence and checking conclusions, and a 

 severer necessity for suspension of judgment. As the bio- 

 logical sciences deal with the laws of life and the phenom- 

 ena of living beings, man in his animal constitution and 

 relations, is included in their subject-matter, while the 

 problems presented exercise the mind in a manner similar to 

 the formation of judgments upon human affairs. Com- 

 plete or demonstrative induction being impossible, we are 

 compelled to form conclusions from only a part of the 

 facts involved, and to anticipate the agreement of the rest. 

 This is reasoning from analogy^ a powerful but perilous 

 mode of proceeding; one which we are compelled con- 

 stantly to adopt in our mental treatment of the concerns 

 of life, and for which biological studies are eminently suited 

 to give the requisite discipline. 



Another advantage of the study of these subjects is 

 afforded by the comprehensiveness and perfection of their 

 classifications. No other subjects compare with zoology 

 and botany in these respects. Not only do they furnish 

 inexhaustible material for the exercise of memory, but by 

 the presentation of facts in their natural relations they 

 exercise it in its highest and most perfect form. It is 

 maintained by Agassiz that classifications in natural his- 

 tory are but reports of the order of Nature — expressions 

 of her profoundest plan ; and he even goes so far as to in- 

 terpret them as a divine ideal programme of constructions, 

 of which the living world is but the execution. However 

 this may be, it is certain that they open to us the broadest 

 view of the relations and harmonies of organic nature, and 

 are best fitte.d to discipline the mind in dealing with large 

 co-ordinations, and the comprehensive arrangement of 



