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A careful observer will not miss the right time; but to make it easier and safer, Lecoq's excellent work is cheerfully recommended. + Lecoq has instituted experiments with nearly all families of phanerogamo, and explained the anthemis in a thorough and most intelligent manner. This work is indispensable to every one who takes an interest in hybridization, and wishes to make experiments. His clear and popular style is understood even by the layman; and there is no other work which treats on this subject in the same plain and scientific way.
After the removal of the anthers, the pollen of the male plant is strewed on the stigma. This is done at the warm, sunny noontime, when the pistil appears covered with a glutinous moisture. The pollen is placed upon the moist pistil by means of a small brush, or camel hair pencil, and the hybridized flower is instantly covered with a gummed gauze, or better, with a glass bell. The glass bell is fixed in the following manner: On a post in the ground, reaching up to the hybridized bloom, a small board is fastened, which has a hole in the middle, through which the twig is drawn, and besides has holes covered with moss to admit fresh air. But if the plant can be placed in a tub or pot, at an isolated place, protected from the influence of strange pollen, the two arrangements named above are unnecessary. Then, if an expansion of the ovary is observed, the impregnation has been successful; and after the removal of all contrivances, the plant is left to itself for further development and maturing the seed. These operations are very simple, but they must be made with care and precaution. The anthers must be removed with great caution, to prevent the bursting of the little sacs, and to avoid any lesion of the pistil. The same caution is necessary, if the calyx is to be slit open in order to remove the anthers maturing before the anthemis. If the pistil does not appear to be covered with a sufficient amount of the glutinous moisture to retain the pollen and to make it burst afterwards, it is advisable to spread, with an. Other small brush, a little juice from the nectary of the same, or another kindred plant, lightly upon the pistil.
Another remarkable property of the pollen, which, in many cases, is very desirable for hybridization, is that it often retains, for a long while, its impregnating power. This is the case with the hemp and corn plant, whose pollen retains its power of impregnation for a whole year, so hat it may be preserved and sent to distant places. This property of the pollen is important, if one wishes to use the pollen of an earlier blooming kind for impregnating a later blooming kind.
† There are no copies of it in the English language.
Finally, it may be well to mention that hybrids cross very readily with one another; therefore, success is tolerably certain if two true hybrids are crossed on each other.
The tools necessary for hybridization are as simple as the operations themselves. Small pincers, several small brushes, a pen knife, several small boxes, in which the pollen is preserved, are all the instruments necessary in these experiments.
The thinking, unbiased husbandman may see at once how useful and advantageous hybridization may be made in agriculture. That the farmer now-a-days claims more cultivated plants than formerly, and always desires better kinds, is proved by the constant importations and commendations of foreign kinds of grain and other plants. These exotice, when they are cultivated here, will often lose their good properties, some even in the first generation, and degenerate more and more in subsequent generations, until, at last, they are much inferior to our native kinds. The causes of this are easily explained; for in most cases these plants have neither the climate, soil, nor other favorable conditions of their native country, on which their good qualities often depend. Thus the English varieties of wheat, and the turnips, will never be fully acclimatized here, because they cannot enjoy the moist, mild atmosphere of England. To try the acclimatization or disacclimatization of such kinds of crops, without any sure prospect of success, would require too much patience and perseverance to recommend it to the practical farmer. If it can be done successfully, it will be accomplished much surer and quicker by hybridization. Any excellent kind of foreign plants, found under more favorable climatic conditions, if crossed with a kind already accustomed to our soil and climate, would doubtless produce hybrids, some of which would possess the excellencies of the former combined with the constancy of the latter; and if hybridization be con. tinued through several generations, the end desired would at last be accomplished.
In some families, especially of the graminea, (grass families,) crosses may be affected in a more simple and empyric way, namely, by sowing the seeds of several varieties of one species mixed together. Among them will be found seeds of those kinds whose properties the farmer wishes to combine or to modify. In the first crop some individuals probably will impregnate each other mutually, and in the next year the equally mixed seed of the whole crop is sown again. From among these plants some individuals are selected which differ most from the others and approximate the type desired; and thus hybridization is continued through several generations, until the end is accomplished. Nature herself, doubtless,
produces a multitude of such hybrids, but they are lost again, because they remain unnoticed.
Not only the cereal plants, but also all other fodder and bulbous plants, and those raised for manufacturing or commercial purposes, may be improved in this way.
The pomologist finds in hybridization not only the means of multiplying, but also of improving his varieties in the true sense of the term.
The art of hybridization is too recent to expect great results from it already; it is still a dark chapter in vegetable physiology, upon which light is yet to be shed by many, very many through-going experiments. Certain rules have, as yet, not been established; when it was supposed in one case to have discovered the laws of nature, it was found to fail in another.
Among practical men, the farmers should, next to the gardeners, feel it to be their calling to institute experiments and collate the results, which would finally reveal the laws of nature governing hybridization.
Why should the husbandman not find leisure and have a desire for ex. periments which will make him better acquainted with vegetable life, so ingenious and interesting, and show him what formerly seemed to be lifeless in a new and peculiar light? What delight could be purer and more pleasing than to call one's self, after some successful experiment, the creator of a new useful plant ?
Agricultural societies should make it an object to institute experiments of hybridization, because some of them have means at their command which the individual husbandman does not possess.
Many, otherwise very intelligent farmers, have relied upon an analysis of soils, to indicate to them the reason why their fields did not produce better crops, when their own good sense should have taught them that the mechanical condition of the soil was the cause of their short and inferior crops. Chemistry could render them no assistance, for the reason stated on a previous page, that chemistry was not investigating the causes of vitality or the surrounding relations of vital functions, but was simply dealing with isolated combinations, both in the organic and inorganic world.
1. Chemistry consists in the knowledge and investigation of elementary matter and its combinations, as well as in the investigation of the manner in which these combinations are produced. The general principle upon which chemistry is based, and, consequently, agricultural as well as technological chemistry, is this: Substances are not created anew; wherever we find such as did not previously exist, we need only to reflect a moment to know that they have been produced by the combination or separation of other materials. Agriculture consists essentially in producing materials of a certain quality in the greatest possible quantity with the least possible
expense of either money or time. This production of materials does not, therefore, consist in a creation, but merely a transformation and re.combination of materials already existing. The materials at hand in the soil and air are, by the process of vegetation, led into the desired combinations,
The science of agriculture treats of three things: 1st. Of the materials to be used, viz: the substances existing in soil and air; 2d. Of the materials already used, and the new form of those substances, i. e., the crop; 3d. Of the manner in which that material is employed so as to produce new substances, i. e., the manner in which the crop is produced from the elements of soil and air by means of the plant.
Chemistry alone cannot solve this problem. If the chemist compares the elements of the soil and air with the substances elaborated from them by the crop, he may, indeed, say, according to the laws of chemistry: "This or that substance or element is wanting in the crop or exists in too small a quantity." He may, furthermore, say: "If this is to be avoided, such and such a substance or element must be at hand in larger quantity in the soil or in the air ;" i. e., he may present an analysis of the crop
and state which substances must be added to soil as manure. He may, moreover, demonstrate by successive analysis at what time each substance is received into the plant and when manuring can most profitably be applied. He may, in addition, state in which form the manure must be used so that the plant may assimilate or elaborate them. From these statements of the chemist, finally, valuable rules may be derived for the cultivation of the soil. Thus far agricultural chemistry has progressed. When the general chemistry of organic combinations will have been farther developed, when we know how starch, sugar, albumen, etc., have been gradually formed by means of combination of elements, agricultural chemistry will afford us much greater results. Then only will this problem be solved, when we know the manner in which every single substance of the crop is formed from the materials of soil and air under co-operation of the materials of seed.
II. How can we, then, ascertain in what manner the substances of the crops are produced from the materials of the soil and air, under the influence of the materials in the seed? Agricultural chemistry heretofore could only compare the crops with the soil and air; it was compelled to leave the third point in the great problem as an unknown quantity; there is a great chasm there ; we compare the beginning with the end, we know the A and the 2, but lying before them there is an immense alphabet unknown to us, viz.: the ratio of the substances absorbed by the plant within the plant.
III. Why may we not expect an exploration of this terra incognita and a filling up of that chasm, a complete knowledge of plant-life from chemistry alone? Why can it not answer all questions put to this science by the
farmer? A complete answer would be too long, and we must be content with brief hints on the principal subject:
a. The process of vegetation is one of incessant changes, that of the germ differing from that of the blooming plant. The phases of plant-life change every hour. An exact chemical knowledge of the process of vegetation could be obtained only by a series of investigations of every cultivated plant, so that the changes of at least every day in the life of the plant would be known. Such an investigation would require not only tens, but hundreds of years.
b. Because we do not know the ultimate extent, the external influences of light, humidity, warmth, electricity, etc., upon the substances contained in the organism.
c. We are really not sure that the process of vegetation is, in fact, any thing, other than a series of chemical processes. We know that different plants are produced from different seeds on the same field, and with the same manure. Each seed contains a specific peculiarity which it retains and propagates. It is not probable that these peculiarities should be merely chemical.
d. It is a fact that the process of vegetation is at the same time and above all a process of formation. The form of the plant is the effect of its life, and also the cause of its further existence; in a word, the plant is an organism, i. e., it forms by its own vitality the means of its further life. The forms assumed by the substances under the influence of vegetation are not merely a conseqence of their chemical proceeding; for these materials are outside the plant, not capable of assuming such forms. Hence follows, that,
e. The process of formation of plants is a manifestation of vitality not yet reduced to chemical laws.
From all this results the important principle: the substances present in the plant originate, indeed, according to chemical laws, but the latter depend at the same time upon the pyhsiological structure of the plant, the form of its root, stem and leaves. Who would, then, exact from chemistry, a science at best beset with so many difficulties that it should every where take into consideration also the anatomical structure and exterior form; it can do so only when assisted by anatomy and physiology.
It will now be obvious why the physiology of plants must aid chemistry to obtain such a knowledge of plant-life as will render agriculture an industrial department founded upon science. Agriculture requires a complete knowledge of plant-life; but this latter is at once both a chemical and a physiological process. In this matter they must operate reciprocally. If the chemist is to be enabled to state at any time the chemical proceedings