SPECIES AND BKEEDS. 135 



might well despair of becoming acquainted with 

 them all, were they not constructed on a few 

 fundamental patterns, so that the study of one 

 Species teaches us a great deal for all the rest. 

 De Candolle, who .was at the same time a great bot- 

 anist and a great teacher, told me once that he 

 could undertake to illustrate the fundamental 

 principles of his science with the aid of a dozen 

 plants judiciously selected, and that it was his 

 unvarying practice to induce students to make a 

 thorough study of a few minor groups of plants, 

 in all their relations to one another, rather than 

 to attempt to gain a superficial acquaintance with 

 a large number of species. The powerful influ- 

 ence he has had upon the progress of Botany 

 vouches for the correctness of his views. Indeed, 

 every profound scholar knows that sound learn- 

 ing can be attained only by this method, and the 

 study of Nature makes no exception to the rule. 

 I would therefore advise every student to select 

 a few representatives from all the Classes, and to 

 study these not only with reference to their spe- 

 cific characters, but as members also of a Genus, 

 of a Family, of an Order, of a Class, and of a 

 Branch. lie will soon convince himself that 

 Species have no more definite and real existence 

 in Nature than all the other divisions of the An- 

 imal Kingdom, and that every animal is the rep- 

 resentative of its Branch, Class, Order, Family, 



