4 



ANALOGY BETWEEN PLANTS AND ANIMALS, 



close to the trunk, and the roots also parcially removed ; but, if the collar 

 remam uninjured, the plant, in suitable soil, and under favourable circum- 

 stances, will throw out new roots and shoots, and in time will completely 

 recover itself. On the other hand, if the collar be cut off, the stem or trunk 

 is left without roots, and the roots without a stem, or the power (in general) 

 to throw up one. 



7. There are some plants of the herbaceous kind (such as the horse-radish, 

 for example) that do not suffer, even if theu* collar should be buried two 

 feet, or even three feet ; but by far the greater number of plants (such as 

 the hepatica, the common daisy, the common grasses, &c.) 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 round the base of its trunk ; and easy to prevent a small 

 one from growing, by lifting it and planting it six inches or a foot deeper than 

 it was before. Hence the great importance of not planting any plant deeper 

 in the soil than it was before taking it up ; and hence also the reason why 

 trees planted in deeply trenched ground, and especially fruit trees, often 

 disappoint the planter. In planting these trees the soil immediately under 

 and about them is more consolidated by treading and watering than the soil 

 in the other parts of the plantation ; and hence it soon sinks below the general 

 level, to maintain which level the gardener fills up the depression every year, 

 till the collar of the tree becomes buried several inches beneath the surface. It 

 is said that all the peach plantations throughout the United States have been 

 for some years in a state of disease, without any person being able to account 

 for the circumstance, or point out a remedy, till one man discovered it to be 

 too deep planting. He proposed to divulge the secret to Congress for a million 

 of dollars; but, while Congress was deliberating on the subject, the secret 

 was made public by Mr. Bridgeman, in a pamphlet published in 1838. The 

 soil in America, Mr. Bridgeman observes, is light ; and the trees, when 

 planted in it, if not staked, are apt to be blo\%Ti aside, or even blown out of 

 the soil, by high winds. Hence, to avoid the trouble and expense of staking, 

 they are planted deeper in the soil, by which they are held firm, without the 

 aid of stakes, and this is the grand cause of unfruitfulness and disease in all 

 trees, more especially in the peach. This deep planting, Mr. Bridgeman 

 contmues, is practised not only with fruit trees in America, but with all other 

 trees and plants whatever; and they are all injured more or less by it, ac- 

 cording as the soil is more or less compact. 



8. The cause why plants are so much injured by burying the collar has 

 not, as far as we know, been physiologically and satisfactorily explained. 



9. The next point of analogy between plants and animals which it may be 

 useful 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 turning the 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 elaboratmg the sap ; and hence plants can no more 

 live without light than without air or food, as light is necessary to turn 

 their food into sap, or, in other words, to bring it into the proper state for 



