Rev. P. Keith 07i the Conditions of Life. 125 



them. If a plant is deprived of the access of the moisture of 

 the soil, it languishes, and withers, and dies. If an animal is 

 deprived for a length of time of all nourishment, a feeling of 

 pain is excited in the region of the stomach, followed by faint- 

 ness and loss of strength, which, without new supplies of food, 

 would ultimately and inevitably terminate in death. As plants 

 cannot range the fields in quest of nourishment, it was necessary 

 that some provision should be made to furnish them with due 

 aliment, without any effort of their own ; accordingly the Creator 

 has provided that they shall find their food in the moisture of 

 the soil in which they grow. Their food is thus already 

 digested, and they take it up in a fluid state by the slow and 

 protracted process of absorption. Animals, on the contrary, 

 having functions to perform incompatible with a stationary 

 mode of existence, and with the assumption of food by the 

 slow process of absorption, are furnished with the means of 

 taking in, at certain intervals pointed out by the sensation 

 of hunger, a competent supply of aliment in a solid state, 

 which they have the means of digesting, and of preparing for 

 final assimilation. — The food of plants consists chiefly in the 

 moisture which they find in the soil, containing in solution a va- 

 riety of alimentary ingredients. But we have reason to believe 

 that they derive part of their food from the atmosphere also. 

 The leaves attract and absorb the moisture. They inhale also 

 its gases; and there are plants that live and thrive without any 

 other food. The Epidendro7i Flos-aeris may be quoted as an 

 example. — The food which animals affect is of various de- 

 scriptions according to the species. Some animals are grani- 

 vorous, as many birds. Some are graminivorous, as the sheep 

 and the ox ; others are carnivorous, as the lion and the tiger. 

 Man eats almost anything, and drinks almost anything, but 

 he likes to have his victuals cooked. 



It has been thought that a line might be drawn dividing the 

 animal from the vegetable kingdom upon the ground of the 

 character of the food affected by each. Such, particularly, is 

 the opinion of M. Mirbel*. Plants feed, it is said, upon un- 

 organized substances — earths, salts, water, gases; animals upon 

 substances already organized ; that is, either upon other animals, 

 or upon vegetables. — We do not regard it as a very good, or a 

 very correct rule. Animals thrive well upon milk alone, which 

 is not an organized substance. If you say that it is the product 

 of an organized being, let it be remembered that it is also 

 a very good food for vegetables. In short, the chief food of 

 plants as well as of animals is cither animal or vegetable sub- 

 stances in a state of solution ; and though animals may 'inciX 



• TraUi d'Anat. cl tie I'/iys. vcg. 



upon 



