having within it a flask-shaped cavity; the surface appears, under the microscope, to consist of a multitude of papillar eminences, and in fact to be anything but flat. Besides these two forms of globular carbonate, there are in the more coloured membranous layers of the oyster regular rhomboidal crystals of carbonate of lime, containing sufficient of the albuminous constituent to leave, after the action of muriatic acid, a residue of the same form. These, in consequence of this residue, are considered by some physiologists to be organic cells.

In shell structures the earthy matter is considered by those who have written upon the subject to be contained in the interior of cells, an idea which presupposes the existence of cells prior to that of the carbonate, which in no way agrees with the appearances presented by the microscope. The order in which the parts appear are, first, a membrane, generally without any marking whatever upon it, which can be taken for cells; secondly, very minute particles of carbonate combined with albumen, so as to leave a residue after being acted upon by muriatic acid; thirdly, the coalescence of these particles into larger globular portions, acted upon in the same way by acid as the smallest particles; so that if this albuminous residue is to be regarded as the membranous cell from which the earthy matter has been dissolved, the very smallest particles which are first deposited are as much cells as the larger globular portions; but it has been shown that precisely the same result can be produced artificially, therefore this residue cannot be regarded either as a true cell or as an infallible test of an organic formation; and lastly, the transformation of these globular portions into laminae or plates, according to the mechanical conditions under which they are placed.

It may be observed that, in some instances where the globular carbonate is deposited near to a membrane having square markings, it seems to follow them so as to appear to be contained in square spaces or cells; but this is completely accidental, as in such cases it more frequently spreads irregularly, and without any limitation from such markings; besides, the membrane on which the carbonate is deposited, or rather formed, is in most instances perfectly homogeneous. Upon the whole I have never, in examining the structure of shells, seen anything to justify the idea of their being composed of organic cells filled with carbonate of lime. The amorphous carbonate which has been mentioned as occupying some of the inter-laminar spaces probably results from the mixture of successive portions of water which finds access to these spaces with the solution of the alkaline carbonate formed by the animal, the latter containing too small a proportion of albumen to form the globular compound. Occasionally in the thin plates of the shell of the oyster, branching dark lines are seen, resembling in their mode of ramification conferva, which in the perfectly calcified shell are so blended with the surrounding parts as to be difficult of satisfactory examination; but in an imperfectly calcified layer they can be entirely detached in their growing condition from the shell, and shown to be in reality what they at first appeared.

access.

In these layers they are found on the surface, to which the water has The otolithes of fishes, and the calcareous concretions found in the pineal gland and other structures, might be shown to be formed in the same manner. But as I have not space for a detailed description of the formation of these structures, and as the concretions abovementioned contain more of the phosphate than carbonate of lime, I shall only make a few observations upon the mode of obtaining an artificial compound identical in its properties with that contained in these deposits, as well as in all normal structures of a similar composition-as, for instance, in bone, and upon the formation of the latter structure.

If pure phosphate of lime be formed and deposited under the same conditions as those mentioned in the process for obtaining the globular carbonate of lime, it does not lose its crystalline character, although its crystals congregate in globular masses; but if a small quantity of carbonate of lime be formed at the same time as the phosphate, these blend together and produce a compound resembling in its form and mechanical properties the globular carbonate of lime. The white of egg contains sufficient alkaline carbonate for that purpose; so that if phosphate of soda and muriate of lime dissolved in separate portions of white of egg be brought into contact and allowed to mix very gradually, a mixture of phosphate and carbonate of lime will result, of a globular form. This compound is not so homogeneous as that of the unmixed carbonate, but its optical and physical characters are very similar.

From this experiment it would appear that the carbonate of lime, found always in combination with the phosphate (as in bone, dentine, &c.), serves to prevent the crystallization of the phosphate, and to cause its particles to coalesce and to blend with other structures—a property which this carbonate has been shown, by its action on glass, to possess in a remarkable degree-and thus to bring the earthy component of bone under the same conditions necessary for the coalescence of its particle as have been shown to exist in respect to shells. To ascertain how far this inference agrees with microscopic appearances, I examined a very low form of bone, one intermediate in some respects between true bone and shell, namely, that to which the muscle moving the claw of the crab is attached. In the very young crab this bone can be seen to be formed by the coalescence of particles of carbonate of lime, exactly like those of the shell. The next bone examined, as particularly favourable for this purpose, was that of a young frog about an inch long. In this reptile the particles of earthy matter are much larger and more distinct than in birds or mammalians. Fig. 7 is a representation of a part taken from the sternum of this frog, preserved in glyceriue; a is a piece of cartilage with nodulated portions of earthy matter formed upon it by the coalescence of previously existing particles, b. These nodulated portions still further coalescing, form osseous rings, which, with others of a similar form and with the cartilaginous matrix, make up the substance of the bone. This car

tilage, as the deposition and coalescence advance, assumes more the character of areolar tissue. The deposit is not formed in the cells of the cartilage, but on the intercellular substance, notwithstanding it does not so follow this substance that the circular areas enclosed by the osseous rings correspond in the least either in number, form, or arrangement with the cells of the cartilage on which they are formed. The circular spaces get smaller as the ossification advances, and they appear ultimately to become the so-called bone-cells or lacunæ. This transformation, or rather process of diminution of these spaces, is by no means difficult to determine, as the same field of the microscope in a good specimen will, at one view, show all the steps of the process.

principle to be the same. The canals of Havers, large at first, become gradually contracted in their calibre by alternate layers of membrane, corresponding to cartilage in the other process, and bone more or less intimately blended together. Hence the appearance of the two structures described by Tomes and De Morgan, as seen in thin transverse sections. Probably the globular dentine described by anatomists is merely the form which the dentine assumes after the coalescence of its primitive particles, corresponding in this respect with the nodulated rings, described in the recently formed bone of the frog; and the dentine canals will perhaps prove to be merely longitudinal spaces, existing in dried sections of teeth, between portions of perfectly formed dentine arranged with different degrees of obliquity around the central pulp cavity. Passages of precisely the same character exist between the analogous portions of enamel, and which are also considered by some as distinct tubes. It is possible that the coalescence does in some instances proceed so far as to produce a circular space entirely surrounded by dentine; but this is probably only an exceptional circumstance, as it does not comport with the function of tubes generally, that a system of such organs intended to convey nutritious matter should either proceed from or terminate in a mere cellular interval, like the cavitas pulpæ dentis, destined to convey blood vessels, nerves, and their connecting areolar tissue. As respects the medium by which the earthy components of bone are brought in a fluid state to the cartilage or membrane, where the ossification is going on, there to undergo

such decomposition as shall result in the formation of the coalescing compound of lime, it may be observed that in one respect the bone, or osseous tendon, above alluded to, of the crab, is circumstanced the same as shell, its membranous covering being, like that of shell, moistened with a solution of carbonate of soda; and in another the same as ordinary bone, for the part on the opposite side of this covering not being, like that in shell, accessible to the fluid medium in which the animal lives, the soluble salts of lime cannot reach it-consequently these salts must be brought into the vicinity of this membrane by some other route. Now as the circulating fluid is intended to introduce into the body the substances of which it is composed, the route for the conveyance of the salts of lime may be inferred, in this instance, to be the blood vessels, and the medium the fluid contained within them. Hence, considering the physiological resemblance, and similarity of the anatomical relations of these structures, there is no improbability in supposing that, as the soft parts contiguous to the dense structure do in the one possess the power of eliminating an alkaline carbonate, a like power should reside also in the corresponding parts of the other; and with respect to the formation and deposition of the earthy components of both these structures, the conditions are precisely the same, the animal to which each belongs being provided with a vascular system. A more complete examination of this question would require further experiments and chemical analyses.

Having, in the preceding observations, shown, as far as experiment and induction can show, that the molecules of what are called hard tissues owe their curvilinear disposition to the direct operation of physical force, it is only a fair inference that the molecules of the less dense ones, being for certainty affected by the same physical forces, and in the same manner, should owe their curvilinear arrangement to the same cause, and that the process of coalescence above described is as applicable to soft as to hard substances, whether they be animal, vegetable, or neither of these, provided they are brought under the conditions necessary for its operation. In the development of the hooklets of the cysticercus cellulose, there is undoubted evidence of coalescence; and as such I have described it in a communication made to the Royal Society in June, 1855, and published in the number of the 'Transactions' for July, 1857, though without a knowledge of the principal facts mentioned in this paper. Possibly some physiologists will consider that, in the explanations of molecular coalescence as applied to organic tissues, physical influence is made to occupy too prominent, and vitality too insignificant, a station; but there are no grounds for such an objection, as these explanations simply rest upon the very obvious and natural inference that vitality, when employing as her agents material substances, makes also available at the same time those physical forces by which these same substances are directly influenced; and that, in the place of opposing these forces to produce effects which it has been shown that they of themselves are perfectly adequate to, she makes them subserve her own purposes. Besides

these explanations are in no way inconsistent with the analogy of nature, as manifested by the tendency which all bodies have to assume a globular form when their component molecules are affected more by the mutual attraction they have one for another than by that of remote objects. But, on the contrary, the mental tracing of the molecules of coalescing spheres according to known laws, and the actual measurement of the distances between their centres, and the exact time occupied in their coalescence, will suggest to the mathematician the elements of new curves, and furnish data for the calculation of rates of velocity, which, considering the inconceivable minuteness of the moving atoms and the inappreciable tardiness of their motion even under the highest magnifying powers, will form a marvellous contrast with the magnitude and velocity of similar atoms when collected into telescopic masses, placed at almost infinite distances, and moving with incalculable speed, although in both extremes of existence they are guided by the same principle of intelligence, and governed by the same laws.*

ART. II.

On the Symptoms of Cancer of the Stomach. By WILLIAM BRINTON, M.D., Fellow of the Royal College of Physicians, Lecturer on Physiology in St. Thomas's Hospital, Physician to the Royal Free Hospital.

To those researches on the Pathology of Cancer of the Stomach,' which have already been laid before the readers of this Review, I am now permitted to add a brief description of the symptoms that reveal the same malady in the living subject.

The symptoms of cancer of the stomach are rendered peculiarly interesting by its well-known fatality and obscurity. And it might fairly be expected that any careful clinical study of these symptoms would bring to light some new details bearing on its diagnosis and

treatment.

But the following essay has more specific claims to interest. The results of recent inquiry into the gastric ulcer demand a careful revision of almost all that has hitherto been written respecting gastric cancer. For while the differential diagnosis of the two diseases obviously implies an accurate knowledge of both, such inquiry has shown, that not only have the frequency and importance of the former disease been greatly undervalued, but its symptoms and appearances so imperfectly known, as to have been often confounded with those of the much rarer malady it can so closely resemble. In this respect I may claim for the following description greater accuracy than has been attainable by most authors on cancer of the stomach. I may add,

*As there may be some persons desirous to see specimens of the objects alluded to above, I have put into the hands of Messrs. Smith and Beck some specimens to be had at a cost not exceeding that at which they were prepared and put up.