250 DR. CARUS ON THE KINGDOMS OF NATURE, 
In examining the origin of the individual members of the vegetative 
sphere, of which we have already observed that the formation from with- 
out toward the internal parts, namely from the umbilical cord into 
the cavity of the stomach, presents the organs of digestion (as the in- 
ternal nourishing root of the animal) and the bowels,—we find that in 
the progress of organization new organs are formed for the functions 
of respiration and secretion, to correspond to those of nutrition and ab- 
sorption. The function of respiration indicates the connexion of the 
individual organism with the atmosphere, as on the other hand the ab- 
sorption of grosser matter indicates its connexion with the earth by the 
root. 
As long as the foetus is inclosed in the placenta it can have no im- 
mediate connexion with the terrestrial organism, but maintains rather a 
reciprocal action with the maternal organism, as is seen in its manner 
of breathing, which is originally performed through the integuments of 
the egg (see p.247), But since it is necessary that an independent 
organ of respiration be prepared for the time when the feetus leaves the 
maternal body and the integuments die away, we find the external sur- 
face of the foetus itself (the skin) developed with its continuation 
(the internal organs of respiration). The vascular system (hitherto 
the connecting medium between the foetus and the integuments of the 
egg, see p. 247), then becomes the connecting medium between the 
organs of digestion, respiration, and secretion. The organs of secre- 
tion, however, may in a certain respect be considered as a repetition of 
the organs of respiration, since the evaporation and secretion of gases 
form a prominent part in the process of respiration. The plant de- 
velops, besides the organs of general assimilation and secretion, those 
of generation: a similar development takes place in the animal also, 
and precisely at the point where the germ of the fruit is developed in 
the plant, at a point which is therefore analogous to the insertion of 
the stamen in the flower; in other words, at the insertion of the umbi- 
lical cord into the abdominal cavity, which in the first stage of forma- 
tion, where we observe the embryo with its pointed lower extremity 
attached to the inner surface of the egg, is the basin that incloses the 
genitalia as the calyx does the fruit-germ. 
After having considered the transition of the form of the plant into 
that of the animal, it remains for us now to examine the peculiarity of 
the active living principle of the animal, in order to ascertain how far 
this is derived from the active living principle of the plant. But we 
must first carefully observe, that if we were right in considering (page 
239) the chief end of the active living principle of the plant to be its 
formation, the first active living principle in the animal likewise must 
be a tendency to acquire individual existence. The whole animal body, 
as far as regards nutrition, growth, secretion, and its being engaged 
