SPECIES AND BREEDS. 135 
might well despair of becoming acquainted with 
them ail, 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. (he 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. He 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, 
