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project, carrying the outer cell-wall before it, so as to form a protuberance, of a bud-shape, which sometimes attains considerable length before any separation of its cavity from the parent-cell takes place. This is effected by the infolding of the primordial utricle, as in case of cell-division, already described ; from which it differs only in the fact that the latter is effected by the equal, while the former is accomplished by the unequal division of the parent-cell.
The first visible stages of the development of new cells, however, do not always take place in the interior of a preexisting generation; for, cells sometimes appear to originate de novo in that mixture of starchy and albuminous fuids, which from its function has been denominated protoplasma. This substance, however, must have always been elaborated by cell-agency; so that, after all, its products must be regarded as the offspring of the cells which formed it. Indeed it is not improbable that cell-germs have existed in this fluid, and escaped detection through their minuteness.
In regard to the rapidity of the process of cell-production, there are many interesting facts : a few must suffice for the present. Extensive tracts of snow in arctic and alpine regions have been seen to be suddenly reddened by the cells of the little Protococcus nivalis, (red snow ;) the phenomenon of honey dew is owing to a similar production. All know the rapidity with which some forms of fungous growth shoot up. A gigantic puff-ball has been known to grow in a single night, from an insignificant size to that of a large gourd ; and from a calculation of the average size of the cells, and of the probable number contained in the full-grown plant, it has been estimated that they must have been generated at the rate of four thousand millions per hour; or more than sixty-six millions per minute. Other instances are doubtless familiar to our readers of rapid growth in vegetable productions. It is probable, however, that much of this result may be attributed to the enlargement of existing-cells, as well as to the formation of new ones.
But it is time to conclude this part of the subject; we pass to the consideration of animal cells, and we shall finish what we have to say on this subject, very briefly ; not because there is not enough of material, for there is an excess; but because of its unfitness for our present purpose.
There are probably no animals, entitled to be regarded as perfect, whose organization is so simple as to consist of a single cell. But this is the earliest condition of all animals as of all plants; and the history of the animal cell, whether thus ranking temporarily as a distinct individual, or occurring as a compo. pent of an aggregated fabric, is essentially the same as that of the vegetable cells whose structure we have examined ; with this exception, that the latter generates the “pabulum” for its sustenance, for which the former is dependent on external supplies.
From this single cell there proceeds all the immense variety of structures and functions, which the living body of the devel. oped and perfected animal exhibits; the nervous system, with its high powers, as vet in a great degree untold ; the blood-vessels, on whose healthy performance of the duties assigned them, life and growth depend; the muscles and the bones constituting the complicated machinery of locomotion; the skin, with its delicacy of touch ; the various internal viscera; the whole, in short, of the many organs and component parts of the system, with all their diverging functions and uses, springs, as we have said, from so humble and obscure an origin as a single cell, or a homogeneous mass of cells, having nothing to distinguish one from the other.
So far as known, the chemical composition of the cell-wall is everywhere the same, being that of the albuminous substances; in this respect, with the cell-wall agrees the primordial utricle of the vegetable cell. It is, however, in the nature of the contents of the cells that the greatest diversity exists. And we should find, if we were permitted to enter on that field, that the various purposes to which the several groups of cells are subservient in the animal economy, (as the formation of bones, nerves, muscles, &c.,) depend on the nature of the materials they select for their development, and the mode in which these are disposed of.
There are two principal modes in which cells may be developed in Animals, as in Plants, viz :—within the cavity of a preëxisting cell, when the process is said to be endogenous; or in the midst of a plastic fluid, termed by physiologists, blastema, which has been elaborated by the agency of cells of a preceding generation. The “nucleus" seems to perform a more important part in the animal economy, than in the plant. As where cells are multiplied by the endogenous process, the nucleus begins to undergo subdivision, as soon as any part of the cell-wall shows traces of inflection.
The doctrine originally put forth by Schwann, who first attempted a generalization on this subject, was, that all animal tissues are immediately developed from cells. Subsequent researches have shown that this was too hasty an induction. And it is not now sustained; for it is found that there are some VOL. XI.
tissues which have no farther dependence on cell-agency than that concerned in the preparation of the plastic material : those parts, however, are the least organized portions of the animal system.
We must somewhere put a limit to our paper, and though we have hardly entered on the broad field of our subject, the present seems as fit a place as any, if we must leave it unfinished; for we cannot pursue it further without entering into details suitable only for the manual, or scientific journal. We think, however, that we have said enough to justify what might have seemed the somewhat extravagant estimate we, in the outset, put upon the science which has furnished the preceding facts.
What branch of physical research presents a more attractive field, than that we have opened in this article !
The Plant and the Animal, in their most perfected forms, we have seen to arise froin an origin so humble as that of a single cell, or mass of similar cells; and it is the province of the physiologist to follow from one development to another the history of organization ; 10 watch the perfecting of the fabric, whether vegetable or animal, as by its process the work of evolution and growth goes on.
The science of physiology, however, has other uses than the gratification of a very natural curiosity in regard to the nature and structure of our own bodies, and of other bodies by which we are surrounded; its results have been applied to other and nobler uses—to the preservation of health, by showing the conditions demanded for the complete performance of all the functions necessary to life ; a department of the science which, were it thoroughly taught as it ought to be, would very soon result in lengthening the average term of human life, besides adding inestimably to the comfort and happiness of the race. And in the highest range of philosophical speculation, physiology has been found to furnish an argument for the existence of Deity more complete and unanswerable than that derived from any other of the Physical Sciences.
We are glad that the necessity of a plea for physiology does not now exist in the same degree as formerly; that to some extent the subject is familiarized to the public mind; and thus its importance is becoming known and appreciated. But even yet it is very far from holding its true position in the public estimation; its revelations are too often held in contempt by those who ought to know better; it has not yet achieved its lawful place in the studies prescribed in our schools and colleges; and the sad consequence of such inattention to its claims too often results in the utter prostration of physical and mental powers, in the destruction of that enjoyment flowing out of the possession of perfect health of body, and in the untimely deaths that are registered in every graveyard.
Our purpose will be served if we have succeeded in commending the subject to the attention of any not previously interested in it, and thus assisting to a recognition of its claims ;-a recognition demanded by the mental, not less than the physical constitution of man.
Art. II.—RESPONSIBILITY FOR ERRORS OF OPINION.
Works of Lord Brougham. London. 4 vols. Sin is the great fact of human society. Hardly inferior to it, in obviousness and magnitude, is its correlate, error. All classes of men, all subjects of thought, and all ages of the world are pervaded by false opinions to an extent which our faculties must accept as infinite.
The wisest is an errorist. In the course of his life, he has been found in a multitude of mistakes, of every degree of importance, from those which relate to the state of the weather, up to those which relate to the essence of religion. Where the strong have failed, the weak have fallen. Amusement and business, politics and literature, science and religion-no field of thought escapes what escapes no intellect. Hardly an opinion which has not been controverted. Hardly a topic on which there are not as many different sentiments as there are different men surveying it for never yet did a moral topic appear to two individuals in precisely the same light. This diversity of opinion measures its erroneousness. The error which lies about us in huge and endless profusion, stretches away in Alpine ranges to the ends of the world, and the beginning of time.
An evil so great and obvious has naturally attracted much attention from thoughtful men. Various inquiries have been started respecting it. Among the most important of these is one relating to the degree of responsibility it involves. Some deny that men are responsible for any of their errors of opinion. They claim that belief is under the control of a rigid necessity—that the judgment is determined by a law of circumstances as inexorable as that which constrains the circling
planet—that believers in God and Jupiter, in Christ and Mohammed, in philosophies empiric and transcendental, in moral distinctions and materialism, are all, in respect to believing otherwise, equally powerless and equally blameless. Others reject these ideas with abhorrence. In their view, all errors involve guilt. No exception is allowed. From religion, down to the smallest matters of etiquette, all our mistakes must be reckoned as falling within the scope of conscience and a moral government. And again, both these views are extreme in the estimation of others—who maintain that we are responsible for all religious errors, or at least all religious errors of the higher degrees of importance, while in inferior matters one may fall into mistake without blame. This last view is that to which the conduct of men is usually adjusted.
Lord Brougham, in his Inaugural Address, as Rector of the University of Glasgow, laid down the broad principle that man is not responsible for his belief. Dr. Wardlaw replied to Lord Brougham, in two very able sermons, though we think not in a manner entirely satisfactory. The subject is evidently of some considerable importance, and we propose to give it an independent investigation.
How far are men responsible for errors of opinion ? Before attempting to answer this inquiry, we must offer a word to prevent misapprehension. Our belief is, that if men were faithful to themselves, they would either avoid all erroneous opinions or escape all their injurious consequences. If God did not secure their fallible natures from mistake, he would prevent their being injured by it. This much we suppose to be taught in the following passages : “ The Lord shall guide thee continually.” “All things shall work together for good to them that love God.” These scriptures promise to secure the strictly righteous from all such mistakes of conduct, and hence of opinion, as would prove injurious to them. They promise nothing more. If God chooses to allow the mistake and prevent its evil results, he does not violate his word. With this precautionary statement, we proceed to inquire how far men are responsible for errors of opinion.
A general and useful answer, is the following: We are responsible for our mistakes as far as they are the result of past sin, or of the absence of due present effort to prevent them: and no further. We shall be asked what we mean by due effort. We answer: effort proportioned to the importance of the subjects to be investigated relative to other subjects claiming our attention. Duty does not require us to expend the entire force of our faculties and opportunities on any one sub