1838] 



FARMERS' REGISTER. 



531 



nttention to llio vo<i;o,lablc kinjidom, will be, by 

 first pointing out ilio principal points of analogy 

 between plants ami animals, and next noticing 

 the structure and lunctions peculiar to plants. 



Plants resemble animals in having an organic 

 structure endowed with lile, and in requiring nou- 

 rishment 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 diller from animals in being fixed to one 

 spot ; in havmg the principles of vitality and re- 

 production di (fused 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 oi" animals. 



The soil in which a plant grows is as essential 

 to it as the stomach is to an animal. Food, be- 

 fore it can be absorbed into the system, must be 

 reduced into a pulpy mass, consisting partly of 

 chyle; or nutritious matter, and partly of relijse. 

 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 as- 

 similated 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 wafer 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 dis- 

 ease, 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 and the stomach be invigorated, and placed 

 in a healthy state, the whole plant or animal will 

 soon recover from the injuries it has received, so 

 as to perform all the functions necessary to its ex- 

 istence. The first step, therefore, in cultivating 

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

 which they grow. 



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 im- 

 mediate 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 

 m.ay 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 point, is immediately beneath 

 the seed leaves ; 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 in various kinds 

 of trees and shrubs, the roots, after a plant hns 

 attained a certain age, become furnished with 



buds ; and, when the plant or tree is cut over by 

 the collar, these dormant buds are culled into ac- 

 tion, and throw up shoots, which are called suck- 

 ers. No sucker, however, is ever thrown up by 

 the roots of a plant cut through at the cellar while 

 in its seed leaves. The branches cf a trccj may 

 be all cut off close to the trunk, and tho roots also 

 partially removed ; but, if the collar remain unin- 

 jured, the plant, in a suitable soil, and under fa- 

 vorable circumstances, will throw out new roots 

 and shoots, and, in time, will completely recover 

 itself. 



There are some plants of the herbaceous kind, 

 (such as the horse-radish, for example,) that do 

 not suffer, even if their collar should be buried two 

 feet or even threa feet ; but by far the greater 

 number of plants, (such as the hepatica, the com- 

 mon daisy, the common grasses, etc.,) are killed 

 by having the collar covered two or three inches ; 

 and nothing is more injurious to woody plants, 

 whether large or small. It is easy to destroy a 

 large tree by heaping up earth around the base of 

 its trunk ; and easy to prevent a small one from 

 growing, by lifting it, and planting it six inches or 

 one loot deeper than it Vv'as before. Hence the 

 great importance of not planting any plant deeper 

 in the soil than it was before taking it up. The 

 cause why plants are so much injured by burying 

 the collar has not, as far as vje know, been phy- 

 siologically explained ; but it probably proceeds 

 from the want of the action of air on the collar^ 

 or on that part of the stem which is immediately 

 above it ; or from the pressure of the soil upon 

 that vital part. 



The next point of analogy between plants and 

 animals, which it may be usefiil to notice, is that 

 between the lungs and the leaves. An animal 

 can no more live without its lungs than without 

 its stomach. The stomach, as we have seen, is 

 necessary for the turning of food into chyle, and 

 the lungs for turning that chyle into blood. Now, 

 a plant can no more live and grow without leaves, 

 than an animal can without lungs. The use of^ 

 the lungs is to expose the chyle to the action of 

 the air,"which they decompose, so that its oxygen 

 may unite with the chyle, and thus change it into 

 blood. The leaves of plants, which act to them 

 as lungs; not only decompose air, but light, in the 

 process of elaborating the sap ; and, herice, 

 plants can no more live without light, than with- 

 out air or food, as light is necessary to turri their 

 food into sap, or, in other words, to bring it into 

 the proper state lor affording them nourishment. 

 Hence, in the culture of plants, the great impor- 

 tance of light. An important difference, however, 

 between the circulation of the sap in vegetables 

 and the blood in animals, is, that the former have 

 no heart. 



Plants and animals agree in requiring a certain 

 degree of temperature to keep them alive ; and 

 the warmth of this temperature differs greatly in 

 the different kinds both of plants and animals. 

 Hence, the constitutional temperature of any 

 plant to be cultivated being known, that tempera- 

 ture must be maintained by art ; either by a suit- 

 able situation in the open air, or by its culture un- 

 der a structure which admits the light, and is ca- 

 pable of having its atmosphere heated to any re- 

 quired degree. The temperature which any plant 

 requires is ascertained by its geographical position 

 in a wild stale ; making allowance for the difiier- 



