250 DR. CARUS OK THE KIN&DOMS 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. Si?). But since it is necessaiy that an independent 

 organ of respiration be prepared for the time when the foetus 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 



