1 1 8 ANATOMY. 



origin of animal existence ; vesicles distend themselves, and become 

 cases ; they link themselves in a series, and form vessels ; and thus, by 

 degrees, each vegetative organ is formed from the vegetable original. 

 We will examine this more closely in the individual organs. 



92. 



The INTESTINAL CANAL is a tube which originated from the elonga- 

 tion of one or the connection of several bladders. This is proved not 

 only by its form in the lower animals, but also from its being in many, 

 likewise in the larva? of insects, a mere blind sack, consequently a 

 bladder open only in front. In animals of a higher grade, in which it 

 consists of several divisions separated by constrictions, it is very easily 

 imagined as consisting of the union of several bladders. 



The same holds good of the vessels : for example, the chief vessel of 

 insects, namely, the large dorsal vessel, so evidently displays a cellular 

 construction that we may not consistently doubt its original growth 

 from bladders. 



The very name of the air-tubes announces their form. It must, how- 

 ever, strike as important that the air-vessels of insects have so deceptive 

 a resemblance to those of plants that everybody mxist immediately 

 admit of their analogous structure. 



The vegetable origin of the nutrimental organs is thus evidently 

 proved. 



93. 



It is not more difficult to show the same in the organs of reproduc- 

 tion. These, namely, very much more distinctly display their vesicular 

 origin. The OVARY of the female is a large bladder, containing many 

 smaller ones, the eggs. The OVIDUCT is an elongation of this large 

 bladder ; the UTERUS is another distension of it, and the VAGINA ano- 

 ther elongation : other incidental appendages of the above parts display 

 more or less distinctly a vesicular form. 



It is the same in the male organs. The testes have not uncommonly 

 the shape of a bladder (Lamellicornid), or else they are long convoluted 

 tubes, which we know to be but modifications of bladders ; the VASA 

 DEFERENTIA are elongations of these bladders; the VESICA SEMINALIS 

 another distension of it, and the DUCTUS EJACULATORIUS another and 

 its final constriction. 



Thus the sexual organs are a still more evident repetition of the 

 ve&icular form, they being always closed at one end at least. 



