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 influence he
has had upon the progress of Botany vouches for the correctness of his
views. Indeed, every profound scholar knows that sound learning 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 specific 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 Animal Kingdom, and that
every animal is the representative of its Branch, Class, Order, Family,
and Genus as much as of its Species, Specific characters are only
those determining size, proportion, color, habits, and relations to
surrounding circumstances and external objects. How superficial, then,
must be any one's knowledge of an animal who studies it only with
relation to its specific characters! He will know nothing of the finish
of special parts of the body,--nothing of the relations between its
form and its structure,--nothing of the relative complication of its
organization as compared with other allied animals,--nothing of the
general mode of execution,--nothing of the plan expressed in that mode
of execution. Yet, with the exception of the ordinal characters, which,
since they imply relative superiority and inferiority, require, of
course, a number of specimens for comparison, his one animal would tell
him all this as well as the specific characters.

All the more comprehensive groups, equally with Species, have a
positive, permanent, specific principle, maintained generation after
generation with all its essential characteristics. Individuals are
the transient representatives of all these organic principles, which
certainly have an independent, immaterial existence, since they outlive
the individuals that embody them, and are no less real after the
generation that has represented them for a time has passed away than
they were before.

From a comparison of a number of well-known Species belonging to a
nat