GENERATION. The production of life has always been a favorite study of scientific minds; All labor, however, to this end, has really added little to our knowledge of the genesis of life. The theory of spontaneous gen eration has been a favorite, dogma with many superior minds, and yet, again, we have no real facts to support the theory. Hence it soon began to lose ground, and is now generally denied by scientific minds. The following condensed arrangements of facts, as stated by the Chemist of the Department of Agriculture of the United States, some years ago, will illustrate how gen eration may become active, as well as give some means of preventing generation, as in preserving substances necessary to be kept intact. (See also Fermentation and Fungi.) In regard to the origin of yeast cells, for instance, we have to con tend with the same conjectures and diversity of opinion as when accounting for the sudden appearance of millions of infusorize in stagnant water or in explaining the origin of intestinal worms. It has been stated that the yeast cells already existed in thejuice of the living grape, and all other kinds of fruit able to yield ferment able juice, such as apples, pears, blackberries, etc. These minute vesicles, it was said, might readily pass through filtering paper, but it is cer tain that filtered juice of fresh fruit when exam ined under the microscope, exhibits no solids, no organized ferment of any kind, but after two of three days apple or pear juice, for instance, will exhibit yeast fungi, and, at the same time begin to ferment. Hence the conclusion is inevitable that we have here to do with a spontaneous cell formation, called generatio equivata or originaria; that is, the yeast plant may, without the tion of a mother plant, originate in a liquid con taining, besides water, sugar, dextrine, (gum,) and albuminous matter. The experiments of Schulze, Schwann, Pasteur, Schroeder, and Dusch favor the idea that the germs of the yeast fungi are diffused in the air and water ready to germinate and multiply whenever a favorable opportunity presents itself, like the eggs of the infusoria which have actually been traced in the air, water, mist, and even snow. Profs. Worm ley and Sullivant, of ColuMbus, 0., have carefully determined that even with the most powerful microscopes, vision is limited to objects of about one eighty-thousandth of an inch in diameter. Now, some infusorim are not more than one twenty-four thousandth of an inch in diameter, and if we suppose that the ova of infusoria and the spores of minute fungi are no more than one-tenth of the linear dimensions of the parent organism, there must be an incalcula ble amount of germs no larger than one two hundred-and-forty thousandth or one one-hun dred thousandth of an inch in diameter, which may appear in putrescible liquids, in far greater num bers than the germs in atmospheric dust, visible by the aid of the microscope, would lead us to expect. Schwann established the experimental proof that when air is first passed through an ignited tube, before coming in contact with the solutions of sugar, containing besides some nitrogenous substances, no fermentation is excited. The same negative result is witnessed when the air is conducted through an apparatus filled with concentrated sulphuric acid (oil of vitriol) or even a strong solution of caustic pot ash, (Schulze) or even when filtered through cotton-wool, (Schroeder and Dusch). Dr. F. Mohr makes some recommendations founded upon Schroeder's experiments, among which we will mention that the casks should be closed, after the wine has ceased fermenting, with a bung, through which passes an air-tight glass tube filled with cotton-wool. Thus the air will be sifted of germs as it enters the cask upon the withdrawal of wine by the stop-cock. The fer mentation previous to that precaution is best con ducted in casks closed by means of a glass tube bent like an inverted letter U, one leg of which is inserted through the perforated bung, while the other dips into water placed in a vessel. By means of this arrangement all the carbonic acid liberated during the fermentation passes out through the water and can easily be watched, while the air is prevented from coming in contact with the liquid• in the barrel. A layer of the heavier carbonic-acid gas on the surface of the liquor makes the exclusion still more complete and pre vents the gathering of mold (Pun du via) though the cask be not full. Without such an arrangement it is impossible to prevent the access of air and spores through the invisible openings and fissures in the stales of the casks. On the other hand a slow oxidation seems desirable, to separate nitrogenous matter and to ripen and improve young wines, whilst the develop ment of the bouquet in older wines seems to be promoted by the exclusion of air or oxy gen. This gas, in fact, destroys it when brought in' free contact with the wine. The germs'being destroyed by heat, chemical agencies, or mechan ically removed from the air, no yeast fungi are formed. From these facts, Appert's method for preserving different kinds of food may find its explanation. Milk, meat, and vegetables are put into tin cans; these are placed in boiling water and immediately hermetically sealed. Liebig's
explanation is that the trace.of oxygen in the air that may still be present with the food is at once taken up by some parts of it without giving rise to the formation of ferment at this high tempera ture; while Schwann believes that by the destruc tive influence of the heat on the germs of fungi and infusoria, the food is preserved. Though. the old theory of spontaneous generation, even when limited to some of the lowest orders of vegetable and animal life, is daily losing ground, and the omne vivum ex ovo has become the axiom with naturalists, still there remain yet many unsettled points in connection with this matter, which require further investigation. Thus if we take it for granted that, according to Gay Lus sac's experiments, a few bubbles of oxygen gas obtained from chlorate of potassa at a high tem perature induce fermentation (when admitted to grape-juice surrounded by an atmosphere of hydrogen or carbonic acid,) it must be admitted that in this case any vegetable germs must have been i excluded, provided that those already pres ent n the juice had been destroyed by boiling, and still fermentation took place ; and if this so, were there no yeast plants present? It must also be remarked that in some of the experiments, where the results appeared to favor spontaneous generation a mercurial bath was made use of, to isolate the substances experimented upon. Pas teur has since ascertained that mercury taken from the bath of any laboratory is itself loaded with organic germs. He likewise found that the contact of the atmospheric air with a fermenting liquor is primarily indispensable, only as being a vehicle for the germs of the various ferments. Vegetable organisms frequently collect as mold in saline solutions, and decompose them; also even in dilate sulphuric acid. They have never as yet been observed in solutions of chromic acid and chroinates, whence these answer well for preserving brains and other highly albuminous anatomical preparations. A solution of tartaric acid will, even when left in tight glass-stoppered bottles, soon become turbid, and lose its acid taste. A microscopic examination will always trace the cause to a formation of mold which I eeds upon the The so-called vinegar Plant is a vegetable organism, and acts as a ferment when brought into dilute alcohol Same mineral waters containing tree sulphuric acid, t.nd tasting strongly sour, are filled with vege table mold. Thermal springs of a very high temperature are not exempt from vegetable productions. Even in poisonous liquids con taining arsenic, etc., we find some species of fungi which flourish and multiply. Ehrenberg, the distinguished Prussian naturalist, who has devoted the greater part of his life to the study of infusorial life, is opposed to a generatto equivoca, and believes that infusorite are developed from eggs. He has described about eight hun dred living species of these microscopic animals, rrldch swarm almost everywhere. They abound in cc•mtless numbers even in the fluids of living and hehlthy animals. Owing to the extreme lightness of these beings we must not he sur prised to learn of their transportation by storms over whole seas and continents. Ehrenberg believes that the baccilarim found upon some steeples at Berlin came originally from South America. In the Alps there is sometin 9s found a snow of a blood-red color; it has been ascer tained that this coloring matter is composed chiefly of a one-celled plant (Protocoe,eus nivalis) of the tribe algce; and, what is most singular, when the snow has been melted for a short time so as to become a little warmer than the freez ing point, these beings die because they can not endure so much heat! The effect of antiseptics in arresting fermentation may be differently explained according as we favor Liebig's or Schwann's theory. The former assumes that corrosive sublimate, arsenic, and creosote, unit ing with the ferment, prevent the decomposition of it, and, in consequence, that of other organic bodies with which it is in contact. Schwann believes that these substances, acting as poisons, destroy the life of the previously described organisms, and that hence the metamorphosis of vegetable substances is arrested by them. We must acknowledge that, notwithstanding the voluminous writings regarding the origin of many of the lowest forms of animal and vege table life, it is yet a mystery, and that here fancy has as great scope as ever. The spontaneous change of azotized organic matter called putre faction is most closely allied to the process of fermentation, being mainly characterized by the evolution of gases of a disagreeable odor, as ammonia, and sulphuretted and phosphoretted hydrogen. For this transposition of elements, moisture, and contact with air, are in the first instance indispensable. It was believed that the animalcules making their appearance in putres cent substances constituted the primary agent or cause of decomposition; and even if more recent investigations have modified this view, it must be admitted that these minute animals hasten and intensify the resolution of the elements.