CHAPTER XIII. 

 ON THE FOOD OF ANIMALS. 



GENERAL CONSIDERATIONS. 



It is scarcely necessary to remind the reader that a constant supply of aliment is demanded 

 by all living beings, from the earliest stage of development, from the germ-cell to that point in 

 existence where the vital forces quit the fabric. The materials vi'hich are subservient to the 

 development of a new being are derived, in the first instance, from the parent ; the higher 

 types of organization are strongly contrasted, however, with the lower, in both the animal and 

 vegetable kingdoms. In the mammalia the new being has its parental connection continued for 

 a long period, comparatively, during which it undergoes a variety of changes, all of which 

 carry it upward to the form and semblance of the parent, so that, at birth, or when it is de- 

 tached from the parent, it has acquired all the distinguishing attributes which belong to it as 

 a species, so far at least as its physical organization is concerned. It has undergone its series 

 of metamorphoses, and now, to complete its development, it has merely to acquire an increase 

 of size. On the contrary, those animals and plants which rank low in the scale of organization, 

 have but a brief parental ^connection ; they are cast out upon the world anil thrown upon their 

 own resources at an early day, and although these are sufficient, ordinarily, to secure the pre- 

 servation and development of the individual, yet, as nature is solicitous for the preservation of 

 the races, she secures this by multiplying to excess, as it were, their germs. The great class of 

 invertebrate animals cast their ova profusely upon the theatre upon which they are to move j 

 and, as if to secure still more perfectly their continuance, they often multiply by buds and by 

 division. The cryptogamia, as in the case of the puff-ball, send forth millions of spores, or of 

 germ-cells, which are capable of developing an individual like the parent, whenever they rest 

 upon a spot suited to their natures ; but millions must perish for want of a suitable spot and 

 medium, upon and in which to exercise their latent functions. 



In the higher vegetables, the germ-cell is surrounded by a store of nutriment, in which all the 

 elements are concentrated which are essential to the first stage of development, or until it can 

 strike its radicles into the soil, from which, in the future, it is to draw its entire supply. Fixed 



