412 Analogy between Plants and Animals. 



when they understand something of the nature of a plant, and 

 of the manner in which it obtains nourishment ; and when they 

 perceive how cultivation operates on it ; they will take a degree 

 of interest in its growth and developement, that a person totally 

 ignorant of these subjects can scarcely form an idea of. 



Plants are organised beings, that, like animals, depend for 

 their existence on nourishment, warmth, air, and light. Their 

 nourishment they derive from the soil, their warmth and air 

 jointly from the soil and the atmosphere, and their light from 

 the sun. As all men may be presumed to know something of the 

 nature of animals, perhaps the easiest way of giving some know- 

 ledge of plants to those who have hitherto paid little attention to 

 the vegetable kingdom will be, by first pointing out the principal 

 points of analogy between plants and animals, and next noticing 

 the structure and functions peculiar to plants. 



Plants resemble animals in having an organic structure en- 

 dowed with life, and in requiring nourishment to enable them to 

 continue to exist. They absorb this nourishment through the 

 small tubular fibres of their roots, in the same way as animals do 

 theirs through the small tubes called lacteals, which convey it 

 from their stomachs. Plants differ from animals in being fixed 

 to one spot ; in having the principles of vitality and reproduc- 

 tion diffused over every part, and in thus being propagated by 

 division, as well as by ova, or seeds ; in being without a brain or 

 nervous system, and, consequently, incapable of feeling ; and in 

 light being as necessary to their existence as air is to that of 

 animals. 



The soil in which a plant grows is as essential to it as the 

 stomach is to an animal. Food, before it can be absorbed into 

 the system, must be reduced into a pulpy mass, consisting partly 

 of chyle, or nutritious matter, and partly of refuse. This pro- 

 cess, in regard to animals, is performed in the stomach, and is 

 called digestion ; and, when it is finished, the lacteals suck the 

 chyle from the mass, and convey it to the lungs, where it is assi- 

 milated to the blood, and thence is distributed through the frame. 



The food of plants is rotted (a process similar to digestion) 

 in the soil ; and is there brought, by the addition of water and 

 gases, to a sufficient state of fluidity to enable the spongioles of the 

 roots to absorb from it the part necessary for the nourishment of 

 the plant. It is then carried up to the leaves, where it undergoes 

 a process similar to that to which the chyle was subjected in the 

 lungs, and becomes true sap, which contributes to the growth of 

 plants, as blood does to that of animals. 



When a plant or an animal is in a state of disease, no appli- 

 cation to the leaves and branches of the one, or to the external 

 members of the other, will be of much use, if the soil or the 

 stomach be neglected. The stem and branches of a plant, and 



