42 DIFFERENCES BETWEEN ANIMALS AND PLANTS. 



lodged in these cavities, is a peculiarity belonging to animals 

 only. In plants, the organs designed for special purposes 

 are never embodied into one mass, but are distributed over 

 various parts of the individual. Thus, the leaves, which 

 answer to the lungs, instead of being condensed into one 

 organ, are scattered independently in countless numbers over 

 the branches. Nor is there any organ corresponding to the 

 brain, the heart, the liver, or the stomach. 



54. Moreover, the presence of a proper digestive cavity 

 involves marked differences between the two kingdoms, in 

 respect to alimentation or the use of food. In plants, the 

 fluids absorbed by the roots are carried, through the trunk 

 and all the branches, to the whole plant, before they arrive 

 at the leaves, where they are to be digested. In animals, 

 on the contrary, the food is at once received into the diges- 

 tive cavity, where it is elaborated ; and it is only after it has 

 been thus dissolved and prepared, that it is introduced into 

 the other parts of the body. The food of animals consists 

 of organized substances, while that of vegetables is derived 

 from inorganic substances ; and they produce albumen, 

 sugar, starch, &c., while animals consume them. 



55. Plants commence their development from a single 

 point, the seed, and, in like manner, all animals are devel- 

 oped from the egg. But the animal germ is the result of 

 successive transformations of the yolk, while nothing similar 

 takes place in the plant. The subsequent development of 

 individuals is for the most part different in the two kingdoms. 

 No limit is usually placed to the increase of plants ; trees 

 put out new branches and new roots as long as they live. 

 Animals, on the contrary, generally have a limited size and 

 figure ; and these once attained, the subsequent changes are 

 accomplished without any increase of volume, or essential 

 alteration of form ; while the appearance of most vegetables 

 is repeatedly modified, in a notable manner, by the develop- 



