ifferent classes, and distributes them among the most eminent
zooelogists of the day.

To Cuvier he intrusts the investigation of that remarkable batrachian,
the Aaeolotel, the mode of development of which is still unknown, but
which remains in its adult state in a condition similar to that of the
tadpole of the frog during the earlier period of its life. Latreille
describes the insects, and Valenciennes the shells and the fishes; but
yet to show that he might have done the work himself, he publishes a
memoir on the anatomical structure of the organs of breathing in the
animals he has preserved, and another upon the tropical monkeys of
America, and another upon the electric properties of the electric eel.
But he was chiefly occupied with investigations in physical geography
and climatology. The first work upon that subject is a dissertation on
the geographical distribution of plants, published in 1817. Many
botanist travellers had observed that in different parts of the world
there are plants not found in others, and that there is a certain
arrangement in that distribution; but Humboldt was the first to see that
this distribution is connected with the temperature of the air as well
as with the altitudes of the surface on which they grow, and he
systematized his researches into a general exposition of the laws by
which the distribution of plants is regulated. Connected with this
subject he made those extensive investigations into the mean temperature
of a large number of places on the surface of the globe, which led to
the drawing of those isothermal lines so important in their influence in
shaping physical geography, and giving accuracy to the mode of
representing natural phenomena. Before Humboldt we had no graphic
representation of complex natural phenomena which made them easily
comprehensible, even to minds of moderate cultivation. He has done that
in a way which has circulated information more extensively, and brought
it to the apprehension more clearly than it could have been done by any
other means.

It is not too much to say that this mode of representing natural
phenomena has made it possible to introduce in our most elementary works
the broad generalizations derived from the investigations of Humboldt in
South America; and that every child in our schools has his mind fed from
the labors of Humboldt's brain, wherever geography is no longer taught
in the old routine.

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