50 VITAL FUNCTIONS OF PLANTS. [iJSCT. .11. 



animals turned outside in* " II est naturel," says 

 he, " de soup9onner que tout vestige de canal in- 

 " testinal finit par disparaitre dans les animaux in- 

 " fusoires*." But this is a mere conjecture; and 

 there is no good reason for supposing that these 

 animals have not an intestinal canal, although the 

 smallness and transparency of their bodies prevent 

 us from detecting it, even with the aid of glasses^. 



Having endeavoured to give you a determinate 

 idea of a vegetable, let us now take a general 

 view of those functions which plants possess in 

 common with other organized bodies, that is, with 

 animals. 



When a plant is examined with care, its struc- 

 ture is found, in many respects, to correspond with 

 that of the animal body, it is composed of solid 

 and fluid parts ; the former comprehending fibres, 

 which are endowed with elasticity and contrac- 

 tility, and vessels in which the fluids move. The 

 most perfect vegetables, however, differ from ani- 

 mals in structure, in having no stomach, heart, 

 brain, nor nerves ; but all these organs are not 



* Elemens de Physiologic veg6tale, &c. t. i. p. U. 



f For practical purposes, as Sir E. J. Smith observes, it is 

 sufficient for the student to know that he may always decide 

 whether " he has found a plant or one of the lower orders of 

 " animals, by the simple experiment of burning:*' the odour of 

 burning animal matter being so essentially different from that of 

 vegetable substances, as not to admit of being mistaken. 



