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THE FARMER'S MAGAZINE 



a very beautiful oi;e. Starch contained a little more charcoal 

 than sugar, and the oxygen of the atmosphere which, as he had 

 said, was one of the requisites for the germination of the seed 

 robbed the starch of a portion of its carbon, and it became sugar, 

 which, being easily soluble, was easily eliminated and absorbed, 

 and became food for the embryo plant. As soon as vital action 

 wa3 excited by this change in the embryo the roots begin (o sink 

 into the ground, the stem to rise towards the air, and the life of 

 the plant is fairly started. Having thus briefly sketched the 

 process of (he germination of the seed, he would refer more par- 

 ticularly to some of the principal points in the general organiza- 

 tion of the plant. The roots were composed of a number of 

 fibrous thread-like organs, from the side of each of which other 

 branches shot out, the whole extending through the soil to a very 

 considerable distance in search of nourishment. The end of each 

 of these roots and rootlets consisted of a spongy body, covered 

 with a delicate membrane, by which all fluids and the principal 

 nourishment which the plant in its early life received must pafs. 

 They passed by what was called the law ©f endosmogis, or 

 absorption from without, a species of capillary attraction purely 

 mechanical in its action, by which the fluids contained in the 

 soil, being thinner than the juices of the plant, passed in; and 

 another current consisting of those parts of the food rot required 

 for the nourishment of the plant was established outwards. The 

 stem, like the stems of all other plants, was formed of what were 

 called the primitive vegetable tissues. The tissues of all plants 

 were composed, he thought they might say entirely, of cells, 

 because the other structures, although difTering at last very much 

 from cells, no doubt were so originally. And not only plants, 

 but every living thing on the face of the earth was made up of 

 vast series of cells. A vegetable cell was a little bag formed of 

 a subsiance very like starch, called cellulose, and containing 

 within it the nucleus or germ of another cell, and a nitrogenous 

 fluid. These cells were contiually forming, so that tissues of all 

 kinds were built up from the lowest embryo to the largest oak 

 that ever grew on earth. In addition to cells strictly so called, 

 there was what was called woody fibre, of which the great mass 

 of the wood in trees was formed. The next point to which he 

 would draw attention were the leaves, which were very important 

 indeed. The leaf was a cellular structure, its cell containing the 

 green substance called chlorophylle. The sap was very similar 

 in all plants, but af er undergoing the process of elaboration in 

 the cells of the leaf, and being exposed to the atmospheric air, it 

 took innumerable different forms. The leaves were furniihed 

 with pores having lip like edges called stomata for imbibing and 

 exhaling moisture and air: they were exceedingly minute and 

 numerous, it being estimated that every lilac leaf contained no 

 less than 160,000. In the great majority of plants the stomata 

 were on the undcr-surface of the leaf, but in the case of those 

 plants which grow upon the water they were placed upon the 

 upper surface — one of the innumerable proofs of wisdom and 

 design of which the world was full. Of course, if in the case of 

 water plants the usual rule had been followed, and the stomata 

 had been placed on the under-surface, ihey could not have im- 

 bibed or exhaled, and the plant would have died. He could say 

 a good deal, did time permit, about the food of plants. The 

 roots imbibed a certain amount of nourishment, but not all ; a 

 great deal was received through the stomata, of which he bad 

 spoken, from the atmospheric air, chiefly in the form of carbonic 

 acid gas. The soil, however, contributed the largest proportion. 

 Soils were formed from rocks. It might te asked, " How could 

 those hard masses of stone be changed and softened into soil?'' 

 It was done principally by the action of plants. Lichens, mosses, 

 and other plants would take root and grow upon rocks where 

 there was scarcely any soil ; and among the excretions from all 

 plants was vinegar, formed by the fermentation of the sugar which 

 they contained. This vinegar acted upon the alkalies contained 

 in the rocks, and disintegrated thorn ; and this process going on 

 through long periods of time to an enormous extent, and being 

 united to the products of vegetable decoii. position, produced soil. 

 The chief constituent of soil was what was called humus, a kind 



of vegetable carbon, and carbonic acid and water nere tlie prin- 

 cipal food of plants. But it was not their only food. Among 

 the other things necessary for their nourishment and grovvth was 

 flint or lime, potash or soda, iron, sulphur, phosphorus, &c. 

 They might wonder how an insoluble substance like flint could 

 be absorbed into the body of a plant through roots so fine that 

 they would admit nothing which was not in a state of solution. 

 The manner in which this wonder was efl'ected was as follows: — 

 A chemical change took place : the silica was converted by the 

 action of the oxygen contained in tlie air into silicic acid; this 

 united with the potash or lime which it found in the soil, and 

 formed silicate of potash, which was soluble, and could conse- 

 quently be imbibed by the plant. Were it not for this provision 

 no plant could grow, because no plant could exist without mine- 

 ral matter, as well as other kinds of nutriment ; it must take up 

 lime or flint, or some of these substances. In the case of wheat 

 which was raised above the soil to a considerable height, the 

 necessary strength of the stalk was given by flint— it was clothed 

 in a flinty coat of mail. The pea, which did not support itself 

 by its own strength, did not require so strong a stalk ; and if a 

 grain of wheat and a pea wore planted together in a pot, the 

 former would take up the flint, but the latter, which did not 

 require it, would not The spongioles which he had mentioned 

 as forming the extremities of the roots, imbibed everything that 

 was soluble ; they were not endowed with a power of selection, 

 but the ultimate cell of the plant had such a power of selecting 

 those elements which were necessary for the nourishment and 

 well-being of the plant, and rejecting all that was useless or 

 hurtful. What a beautiful provision! An exception was some- 

 times taken, indeed, to the use of the word " beauty" in such an 

 application as this; but to his mind it was no less appropriate 

 with such a reference than it was when applied to the charms of 

 form or colour, or eloquence of music. In the latter there was 

 something sensuous mixed up with the mental emotion of plea- 

 sure; but in the former, the delight was purely intellectual, 

 bringing us cloier to the Divine creative thought, awakening the 

 highest faculties and feelings of the soul, and, in the striking lan- 

 guage of the poet, leading us " through Nature up to Nature's 

 God." He now came to speak of the flower of wheat. The 

 flower of all plants, as they knew, was composed of certain organs 

 and certain coloured or green leaves. In the case of the wheat 

 there was no coloured flower. It consisted of two green leaves 

 called glumes, two others called palese, and two small scales 

 which were attached to the base of the ovule; it also contained a 

 pistil, stamens, anthers, &c., like other flowers. The pollen, 

 which was contained in the anthers, was, in fact, the embryo 

 which, after undergoing certain changes, was to find its way 

 into the young germ, and become the future plant. By a very 

 beautiful provision, the pollen grain, which fell upon the feathery 

 stigma of the wheat, was carried by a tube which sprung from 

 the case of the pollen grain through the style to the ovule ; as 

 soon as it got there, starch and gluten were deposited around it, 

 and it was developed into the perfect seed. He believed that his 

 friend. Dr. Duncan, was at present engaged in investigations 

 upon this part of the subject, the result of which would probably 

 throw additional light upon some parts of the wonderful process 

 which he had briefly described. (Dr. Bree illustrated this part 

 of his lecture by a frequent reference to numerous coloured dia- 

 grams). Such was the natural history of a grain of wheat ; for 

 when it had reached the stage to which he had now conducted it, 

 it was given over to the farmer to be converted into bread, or to 

 form the seed for the ensuing year, and the object of its life was 

 accomplished. In all the stages of its history the wheat plant 

 passed through many dangers, to some of which, known as diseases 

 of wheat, he would, in conclusion, briefly refer. In the first 

 place, it was attacked by various fungi, such as the well-known 

 mildew, the red-robin or rust, the pepper brand, &c. All these 

 were fungi which attacked and often blighted the stalks and ears 

 of wheat. Another disease was what was commonly called cockles, 

 which consisted of a large number of eel-like animalcules, which 

 were generated in the ears, which (hey consumed and destroyed- 



