BOTANY. 



BOTANY. 



536 



functions of the human body will find it necessary to begin his 

 inquiries by the study of the nature of vegetable cells. It was by 

 following up the researches made by Schleiden on vegetable cells, 

 that Schwann was enabled to demonstrate the cellular structure of 

 the animal body, and thus to initiate a new era in physiology. It is 

 still in the plant that the simplest condition of the cell is observed. 

 It is also in the plant that the greatest chemical activity of the cell 

 exists. The food of animals, and that which constitutes the substance 

 of the tissues of animals, are all formed in the interior of the cells of 

 plants. It is the cell of the plant which appropriates the carbonic 

 acid of the atmosphere, and throws back again into it oxygen gas ; 

 on the one hand depriving it of an agent destructive to animal life, 

 and on the other supplying the agent by which alone animal life 

 could be carried on. It is also in the vegetable cell that the chemist 

 must seek the solution of some of the most difficult problems of 

 it-nee. The chemist canuot convert carbonic acid and ammonia 

 into protein, sugar, starch, &c. processes which are going on in every 

 vegetable cell ; he must therefore regard attentively the changes 

 going on in the cells of plants, if he would manufacture the products 

 of the vegetable kingdom independent of its aid. 



Amongst the practical arts of life a knowledge of Botany is impor- 

 tant to many. Agriculture and Horticulture are the two arts with 

 which its relation is the most obvious ; for although a considerable 

 part of all the practices in each of them grew out of mere experience, 

 or was discovered by chance, yet there is no possibility of improving 

 them except by other fortunate accidents, or of advancing them at a 

 more rapid rate, unless by the application of vegetable physiology. 

 The world, especially that part of it to which these arts belong, is 

 little accustomed to trace to their source the common practices 

 with which it has been familiar from its infancy ; and it is far from 

 suspecting that many of the operations which are intrusted to the 

 most ignorant rustics have one by one and piecemeal been hit upon 

 during the careful study of nature by philosophers whose names it 

 never heard. Gardening and Husbandry may be defined as the arts, 

 firstly, of improving the quality of various useful plants, and secondly, 

 of increasing the quantity which a given space of earth is capable 

 of producing. 



To improve the quality of any one plant, and to render it better 

 adapted to the uses of mankind upon scientific principles, is a very 

 complicated process, and is to be effected in many different ways, 

 all of which require an intimate knowledge of the nature of the 

 vital actions of plants, and of the degree in which they are affected 

 by either external or internal causes. For example, a particular kind 

 of flax produces fibres which are too coarse for the manufacturer ; it 

 is impossible to know how those delicate elementary tubes are to 

 be rendered fine without being aware of the manner in which vege- 

 table tissue is affected by light, air, and earth. The flavour of some 

 fruit is too acid ; it is the botanist only who could have discovered 

 how to increase the quantity of saccharine matter. Potatoes are 

 sometimes watery and unfit for food ; we learn from vegetable 

 physiology that this is often caused by the leaves not being sufficiently 

 exposed to solar light, the great agent in causing the production of 

 vegetable secretions. The leaves of the tea plant are harmless and 

 only slightly stimulating in certain latitudes; they become narcotic 

 and unwholesome in others; this apparent puzzle is explained by 

 the connection that exists between climate and vegetation, a purely 

 botanical question. Certain races of plants may exist, of which one 

 is too vigorous, the other too debilitated for the purposes of the 

 cultivator; the botanist shows how an intermediate race may be 

 created, having the best qualites of both. 



Certain vegetable productions are susceptible of being produced in 

 particular latitudes, others are not, or not to any useful purpose : 

 for instance, in England, on account of the want of the necessary 

 heat at the period of ripening the grape, the vine will never yield 

 grapes capable of making such wine as even that of champagne, nor 

 will tobacco ever acquire that peculiar principle which gives it so 

 great a value in tropical and subtropical climates when grown in other 

 countries ; and yet both these plants flourish in the soil of England. 

 The botanist can explain the cause of this, and thus prevent the 

 commencement of speculations which can. never end except in loss 

 and disappointment. 



The quantity of produce which may be procured from a given 

 space of ground varies very much according to the skill of the 

 cultivator, but that skill is in reality the mere application of the rules 

 nf vegetable physiology to each particular case ; an application that 

 is most frequently made unconsciously, but which nevertheless is 

 made. We are too apt to overlook causes in effects, and to ascribe 

 the improvements we witness to a mere advance in art, without 

 [ring that that advance must have had a cause, and that the 

 cause can only be the working of some master-hand which is after- 

 wards blindly followed by the community. The crops of orchard- 

 fruit are doubled and trebled in many places : old exhausted races 

 are replaced by young, vigorous, and prolific ones ; the cider and 

 perry farmer will feel the benefit of this, but he will forget that he 

 owes the change to the patient skill of a vegetable physiologist. The 

 produce of the potato is augmented in the same proportion ; twice 

 at least the ordinary quantity of this important article of food may 

 now be obtained from every field. The peasant will feel the additional 



comfort thus diffused around him, but he will never have heard of 

 the name of Knight ; nor will he know, after a few years, that the 

 produce of the land was ever smaller. 



Nor is it alone to articles of food that this science is to be applied. 

 Next in importance to food are fire and shelter, both of which are 

 mainly furnished by timber. The laws of nature which regulate the 

 production of this substance are among the most curious in science : 

 we possess the most absolute control over them ; we hold in our very 

 hands the means of regulating their action ; and if we neglect them, as 

 is too often the case, it is not science which is to blame, but those 

 who undervalue and neglect her. Because trees will grow without 

 assistance, and because in spite of neglect and ignorauce timber is 

 perpetually renewing itself upon the earth, we forget that either its 

 rate of production may be accelerated or its quality improved. 

 Instances are not wanting where plantations in this country made for 

 particular purposes at a large expense have been totally ruined, with 

 reference to the objects of those who planted them, from ignorance of 

 the simplest laws of vegetable physiology. 



Some allusion has already been made to the important results 

 which arise out of the study of the connection between vegetation and 

 climate. The quality of all vegetable productions is influenced essen- 

 tially by external causes ; intensity of light, atmospheric pressure, 

 humidity, temperature, and seasons, are the great agents which modify 

 the tissue, which control development, and which regulate the forma- 

 tion of sensible properties. Various combinations of these and other 

 external causes are what constitute diversities of climate, and it is 

 therefore obvious that the connection between the latter and vegetation 

 is of the most intimate nature. But as this is a branch of the science 

 of comparatively modern origin there are few instances of its appli- 

 cation : one of the most striking was the declaration of Dr. Koyle, that 

 cotton might be obtained in the East Indies equal to the finest from 

 America a prophecy which has already been fulfilled, in consequence 

 of the practical adoption of plans similar to those which he theoreti- 

 cally suggested. Can tea be cultivated as advantageously elsewhere 

 as in China ! Here is a single question of immense importance, in- 

 volving the interests of millions of human beings, and affecting the 

 pecuniary interests of Great Britain as much as any commercial 

 problem ever did. This question has been answered by the botanist 

 in the affirmative, and already the natives of the East Indies are 

 supplied with tea from the Himalaya, and Asam tea may be bought 

 in the shops of London. 



To the medical man the study of botany is of the highest interest, 

 as the members of the vegetable kingdom yield to him the most 

 important means of his art. It is only as the properties of plants are 

 studied that new agents for the alleviation of disease can be expected, 

 or that substitutes for those already in use cau be employed. 



Thus far we have more especially referred to the study of vegetable 

 physiology. Systematic Botany bears upon practice not less usefully, 

 but in a different way. If the only advantage of classifying plants 

 were to acquire the power of discovering their scientific names, even 

 that would have a certain kind of interest, because it would ensure a 

 uniformity of language in speaking of them ; if it had the additional 

 property of demonstrating the gradual connection that is discoverable 

 between all the beings in the organised part of the creation, of proving 

 that there is an insensible transition from one form of living matter 

 to another without break or interruption, and of explaining in a clear 

 and intelligible manner the nature of that universal harmony of 

 which philosophers are used to talk, the interest and importance of 

 botanical classifications would be still further enhanced ; but the 

 practical importance of them would still be extremely limited. It is 

 only when we look to the coincidence between botanical affinities and 

 sensible properties, and to the external indications of internal qualities, 

 that we perceive the great features of its utility to man. If the 

 qualities of every plant required to be ascertained by a circuitous and 

 tedious series of experiments, no life could be long enough for the 

 task, nor, if it were, could any memory however powerful remember so 

 extensive a series of facts ; and if under such circumstances botanists 

 whose whole life is occupied in the study should be unable to master 

 the difficulties, systematic botany could never be applied at all to any 

 useful purpose, because it must of necessity be far beyond the 

 acquirement of those persons who would be most likely to have occa- 

 sion to employ it. But it was long since suspected that plants which 

 agree with each other in organisation also agree in the secretions 

 which may be supposed to be the result of that organisation. Lin- 

 naeus, in his dissertation upon the properties of plants, declares that 

 species of the same genus possess similar virtues, that those of the 

 same natural order are near each other in properties, and that those 

 which belong to the same natural class have also some relation to 

 each other in their sensible properties. This doctrine is now admitted 

 on all hands among men of science to be incontrovertible, and places 

 the practical utility of systematic botany in the most striking light. 

 Instead of endless experiments leading to multitudes of incongruous 

 and isolated facts, the whole history of the medicinal or economical 

 uses of the vegetable kingdom is reduced to a comparatively small 

 number of general laws ; and a student instead of being compelled to 

 entangle himself in a maze of specific distinctions, is only obliged in 

 practice to make himself acquainted with the more striking groups ; 

 nnd having accomplished this he is enabled to judge of the properties 



