ANALOGY BETWEEN PLANTS AND ANIMALS. 3 



same way as animals do theirs through the small tubes called laeteals, which 

 convey it from their stomachs to their lungs. Plants differ from animals in 

 being fixed to one spot, in having the principles of vitality and reproduc- 

 tion diffused over every part of their structure, 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 neces- 

 sary to their existence as air is to that of animals. 



3. The soil in which a plant grows is, in general, 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 nutritious matter 

 soluble in water, and partly of refuse. This process, 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 

 assimilated to the blood, and thence is distributed through the frame, while 

 the refuse is passed off in the form of excrement. 



4. The food of plants is rotted, or undergoes the putrescent fermentation 

 or some other species of decomposition, (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. The matter 

 absorbed is then carried up to the leaves, where it undergoes a process 

 similar to that to which the chyle is subjected in the lungs of animals, and 

 becomes the true sap of the plant, which contributes to its growth as blood 

 does to the growth of animals. 



5. When a plant or an animal is in a state of disease, no application 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 the external members of an animal, may be 

 injured, mutilated, and even diseased ; but if the soil of the plant and the 

 sto'mach of the animal be invigorated, and placed in a healthy state, the 

 whole plant or animal will soon recover from the injuries it had received, 

 so as to perform all the functions necessary to its existence. The first step, 

 therefore, in cultivating or in improving plants, is to improve the soil in 

 which they grow ; and in like manner the first step in improving animals is 

 to improve the quality and increase the quantity of their food. 



G. In all vertebrate animals there is a part at the back of the neck, 

 between the spinal marrow and the brain, where a serious injury will occasion 

 immediate death. There is a corresponding point in plants, between the 

 root and the stem, which is called the neck, or collar ; and at this point 

 plants may be more readily injured than any where else. Most plants, also, 

 may be killed by covering this point too deeply with soil. In all seedling 

 plants, this neck or vital part is immediately beneath the point where the 

 seed-leaves originate ; and if the plant be cut over there when in a young 

 state, the part which is left in the ground will infallibly die. In old plants, 

 however, and particularly in herbaceous plants which have creeping stems, 

 and also in various kinds of trees and shrubs, the roots, after the plant has 

 attained a certain age, become furnished with adventitious buds ; and, when 

 the plant or tree is cut over by the collar, these dormant buds are called 

 into action, and throw up shoots, which are called suckers. No suckers, 

 however, are ever thrown up by the roots of a plant cut through at the 

 collar while in its seed-leaves. The branches of a tree may be all cut off 



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