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tion; in short, it is a species of attachment somewhat similar to that which a sailor feels for the ship in whose management, distresses, dangers, and exploits, he has taken an active share.

In speaking of the different modes of illuminating objects, there is a long paragraph on directing the light obliquely, by turning the mirror aside (p. 352). The phenomena described are much more readily produced by employing the diaphragm of Le Bailliff, which, in our opinion, is indispensable to a good microscope, and of which, by the bye, nothing is said. The directions for illuminating opaque objects, a point of much practical importance to the anatomist, are very unsatisfactory. We suspect that if the author had been in the habit of illuminating certain opaque anatomical preparations, such as very fine injections for example, he would find the "bull's eye, or hemispherical lens of four inches in diameter" very insufficient.

The following passage is good, and conveys practical and useful information. It refers to drawing objects by means of the camera lucida.

"Much will depend upon the advantageous adjustment of the amount of light upon the object and the paper respectively. In drawing or measuring by lamp light, we have found it useful to place a small taper near the screen, so that its direct rays may fall upon it, whilst the lamp is used for illuminating the object; and when the screen is illuminated by daylight, it is preferable still to use the lamp for the other purpose. The point of the pencil should be blackened. The micrometer eye-piece also may be employed for drawing; its squares being represented by squares on the paper; and the portion of the object between each being delineated in the manner commonly practised by artists. No assistance of this kind, however, can supply that skill to the microscopic draughtsman, which is required for making finished delineations of any object. Accuracy of outline is all that they can insure." P. 356.

From what we have said of this article, our readers perceive that it is not at all suitable to the work in which it appears. The anatomist and physiologist can derive very little benefit from its perusal, and the practical physician or the student will find in it few inducements to adopt the instrument as a means of research, and nothing to guide him should he make the attempt.

Dr Gerber's work, from being the first which has appeared in the English language, devoted to a systematic consideration of histology, based on microscopic researches, as well as from its intrinsic merit, demands our attention. It conveys to us in a compendious form, a general idea of the present pathological notions of the German school, which, if true, must modify in a great measure many of the doctrines generally received in this country. The views alluded to, unquestionably claim the careful attention of all who are interested in the progress of medical

science. On this account, and because the work contains so much that is new and interesting, we feel called upon to devote more than usual space to an analysis of its contents.

We must premise, however, that the work contains nothing of general anatomy, properly so called; that is of the kind of anatomy so ably treated by Bichat and Beclard, and is in fact only valuable for its histological information. It is drawn up in the form of numbered paragraphs, under various heads, constituting a species of compendium or outline. There are no minute observations or details given, which is much to be regretted, when we take into account the novelty and importance of many of the statements brought forward. Indeed the summary and decided manner with which this author has settled some of the most difficult and intricate questions in anatomy, physiology, and pathology, renders it necessary for us to caution the inexperienced, not to receive too readily all the assertions he has made, some of which, as we shall afterwards see, are sufficiently startling. The author has not overlooked the histological changes produced by disease, nor lost sight of organic chemistry in his researches, proving to us that his ideas, in common with those of his countrymen generally, regarding the proper mode in which structure. ought to be studied, are founded on an enlarged and philosophic basis. If the microscope is ever to confer benefit on medicine as a practical art, it is combined with such knowledge, that it ought to be applied. We fully concur in the following remarks.

"The microscope, now recognised as indispensable in general and pathological anatomy, ought also to take its place among the implements most needful to the practical physician. It seems impossible, indeed, to over-estimate the extent to which the science and art of medicine would be advantaged, were every well-informed and zealous practitioner carefully to examine each morbid product he encountered, and to communicate the result of his inquiries along with a compendious history of the case." Preface vi.

The notes and appendix of Mr Gulliver add considerably to the value of the work. With this general statement of our opinion, we proceed to give our readers an analysis of its contents.

After giving a general review of the chemical constituents of the animal body, and of the interchanges and general transformations of organic matter, we are presented with the following passage on what the author calls the hyaline or vitreous substance:

"The hyaline or vitreous substance forms a considerable constituent element in the animal body. Although amorphous in itself, it must still be associated with the organic parts, inasmuch as it is formed contemporaneously with other more highly organized elements, as it stands in a certain relationship to these,and for its maintenance requires, like them, a perpetual interchange of substance. The vitreous element is translucent in every degree to perfect transparency; it is colourless, or but slightly tinged; gene

rally it is of firm consistence, and highly elastic. It serves as a transparent medium for optical purposes, as in the crystalline lens of the eye; as a protecting and sheathing medium, as in the Whartonian pulp of the umbilical cord; or as an elastic bond of union,-as an intercellular substance, for instance, in the cell including vitreous matter of cellular cartilage, in the cartilage of the bones, and in the canalicular or tubular structure of the teeth." Pp. 27, 28.

Thus, this hyaline substance is considered by the author as being imperfectly organized-a step removed from solids, precipitates, crystals, gravel, accidental or mechanically formed concretions, and so on. No doubt, if it be not organized, it possesses the germs of organization, and probably, as our means of investigation are improved, these may even be detected. We know that the hyaline substance of some cartilages becomes developed into bone or fibrous matter. The recent researches of Mr Nasmyth also have shown, that the intertubular substance of the teeth is composed of cells, and is consequently more highly organized than the author supposes.

Amongst the animal constituents placed higher in the scale of organization than the hyaline substance, the author places Fibrine. On this point he observes,

"The fibrine which is held dissolved in the serum of the blood and of the lymph may be regarded as the general formative element or blastema-that principle which, under the influence of the primary and secondary organic processes, is fitted to assume all the shapes which we observe in the constituent parts of animal bodies. Fibrine left at rest, consolidates, under all circumstances short of those which act by decomposing it, first into a determinate hyaline substance, which in the greatly debilitated and in the dead body, and also out of the body, when left to itself, falls into granules, or forms an aggregated granular mass." (P. 28.) "When it coagulates

in contact with the interior of the living body, immediately higher organic processes are proclaimed in the formation of compound corpuscles, which either swim free in the fluid, as the globules do in the blood, or they appear as isolated bodies disseminated through a hyaline substance, or variously arranged without any common bond of union, and so obtain their final development; or they present themselves as mere transition forms of more highly organized products, which, with the final completion of the development, disappear entirely." Pp. 34, 35.

To these corpuscles he gives the same name which Schleiden applied to similar bodies in the vegetable kingdom, viz. cytoblasts, cell germs, or encased nucleoli.

The following forms the basis of the author's classification of animal structures :

"In animal bodies, two classes of solid precipitates from vital fluids may be distinguished, each of which has a different organic signification. Some are objective, i. e. they form no immediate integral part, essential to the life of the organization; and others are subjective, i. e. they form immediate, original, and indispensably necessary parts of the body. In other words, we have aplastic elements-elements susceptible of no farther amount of organization; and plastic elements-elements which bear within them the

germs of higher forms. Each of these classes of elements forms two orders, The objective or plastic fall into, 1st, inorganic crystalline; and, 2d, semiorganic non-crystalline, mechanically fashioned. The inherently vital cell germs again divide themselves into (a) monoplastic, which retain their primary forms; and (b) polyplastic, which lose their primary shapes, transform themselves into all the organic forms, and in fact are destined to one that is higher." Pp. 35, 36.

The organic granules, which constitute so large a portion of animal textures, are thus spoken of:

"The precipitate of extremely minute, soft, organic granules, so universally encountered in the animal body, appears for the most part to consist of albumen. These granules would seem only to form cell germs, or nucleolated nuclei, when the coagulation of the fibrine takes place otherwise than in vital association with the internal structures of the individual who engenders it. There is scarcely a watery or mixed animal fluid without its granules. Wherever albumen in solution is met with, there will granules be discovered." P. 37.

And yet farther on, he observes,

"The number of granules present, never bears any kind of ratio to the quantity of albumen in solution; so that a fluid which contains albumen in the proportion of fourteen, may present no more granules than one which contains albumen in no higher a proportion than one. The nucleus of a cell germ, the nucleolus of a nucleated cell, often exhibits the precise appearance of a granule; but it can never be confounded with this, nor ought it ever to be spoken of as synonymous with a formation of so much lower significance." P. 40.

We cannot help thinking that there is some obscurity here; for we have puzzled ourselves in vain to make out whether the author draws any distinction between albuminous and fibrinous granules; and if so, in what the nature of that difference consists. Mr Gulliver adds a long and valuable note on this subject, the importance of which fully warrants his dwelling upon it. Indeed, we cannot but feel grateful to this gentleman, for the information he has contributed to the mysterious process connected with the effusions and morbid changes of fibrinous matter. He has the merit, for instance, of having satisfactorily shown that the substance which Gendrin and Andral have described as constituting a collection of pus in the clots of blood-abscesses of the blood, so to speak-was in point of fact, only softened fibrine, a result much more consistent with our notions of correctness. He has also found in clotted fibrine, simple and compound corpuscles, and in a few instances, true cells a circumstance which would place this substance, even at an early period, amongst a higher class of organized materials than previous observers have been willing to admit. We recommend, however, a careful perusal of Mr Gulliver's note, commencing at page 28.

The author now enters upon a consideration of the cell germ, encased nucleus, or cytoblast of Schleiden, The theory of the

cellular origin of all tissues, animal as well as vegetable, which the researches of Schleiden, Schwann, Valentin, and others, have developed, appears now to have been generally received amongst scientific observers. Undoubtedly it clears up a host of phenomena which were previously obscure; and although far from complete-although demonstrative evidence is still wanting, that many animal tissues were at any time wholly constituted of cells -it renders the assumption of this in the highest degree probable. The terms nucleolus, nucleus, and cell, therefore, have now become common expressions amongst anatomists, physiologists, and pathologists; and a knowledge of their mode of production, their mutual relation to each other, the mode in which they become developed into all the textures of the body, and the forms they assume in certain morbid structures, must henceforth be considered as forming a portion of that knowledge which every enlightened medical practitioner ought to possess. It is in these particulars that we must acknowledge the superiority of the Germans to ourselves a superiority, we are afraid, which will continue until the medical professors and teachers in this country consent not only to describe, bnt demonstrate these things; and instead of coldly looking at all attempts to introduce the microscope as a means of research, are themselves obliged to employ it, and stimulate the exertions of the student by their own example.

The general formation of cells may be shortly described as follows. There is first a granular fluid; secondly, a nucleus is formed, which some have described as being made of an aggregation of these granules, and others as a corpuscle of a white, or dull red colour, enclosing a granule or nucleolus. Upon this nucleus arises a transparent vesicle, at first somewhat resembling the appearance of a watch glass rising from the dial of a watch, and then the whole constitutes a nucleated cell. The walls of the cell now enlarge. If several lie together, they assume a polyhedral form from the lateral pressure they receive, as in the pith of some plants; fibres are formed, from their becoming elongated, and splitting up; tubes, from the partitions being absorbed, whilst the walls remain; and more solid textures, from woody or calcareous depositions taking place on their internal walls. After a time, the nucleus disappears, leaving a non-nucleated cell; but it sometimes remains permanently. It must not be supposed, however, that every granular fluid gives rise to a nucleus; every nucleus to a cell; or that every cell assists in forming other textures. Granules, nuclei, and cells, often remain permanently, thus constituting the basis of several animal fluids or textures. Different observers have considered this or that corpuscle to be a nucleus or a cell, according to their ideas of its formation and state of development. Thus, Schwann regards the red particles

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