MONOGRAPH OF THE FALCONIDiE, 
opinions and judge for themselves. Before, however, introducing 
the reader to my arrangement of the Falcons, I must first exhibit 
the classification, not only of the class of birds, but also give a 
sketch of that of all animals, because the special arrangement 
may not be understood without a survey of the whole. I must 
even go farther, and point out the anatomical structure of the animal 
body, and how the organs of the senses, which are the principal 
members of the systems, appear in the different classes. In this 
doctrine I follow my worthy friend Oken : and I only differ from 
him in one point, viz., that I recognise in the Insecta and Radiata 
the same systems as in the true animals. 
The animal body consists of the following systems, of which I 
suppose one to attain perfection in each single class of the animal 
kingdom. 
I. The system of the nerves, whose prime member is the Eye. 
It is only affected by the light, and like the nervous system, it 
attains in man, of all the Mammalia, its highest perfection. 
II. That of the organs of respiration , to which the Ear corres- 
ponds. It is sensible only to the air in motion, and like the re- 
spiratory system, it attains its perfection first in the class of Birds. 
III. That of the hones , to which the Nose corresponds, with its 
fine filligree nose-shell, covered with nervous membranes. It is 
only affected by the air when pregnant with particles of certain 
substances. In the Reptiles, there first appears a pierced nose, 
respiring the elastic air. 
IV. That of the nourishing organs , to which the Tongue cor- 
responds. It is sensible only to substances which dissolve in water. 
It generally appears first in the class of Fish, and there, is very 
complicated in the ligaments of the tongue, that support the gills, 
which are the representatives of the respiratory organs. 
\ . That of the organs of the membranes , to which the Geni- 
talia or sexual organs correspond. They are only sensible to 
warmth and cold. They appear, conjointly w ith the genital organs, 
very complete in the Mollusca. 
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