made by previous experimenters, showed that this whole class of phenomena are essentially similar, and called this manifestation of power simply "osmose."

While studying osmotic action, Graham was led to one of his most important generalizations, the recognition of the crystalline and amorphous states as fundamental distinctions in chemistry. Bodies in the first state he calls crystalloids; those in the last state, colloids (resembling glue). That there is a difference in structure between crystalloids, like sugar or feldspar, and colloids, like barley candy or glass, has of course always been evident to the most superficial observer; but Graham was the first to recognize in these external differences two fundamentally distinct conditions of matter not peculiar to certain substances, but underlying all chemical differences, and appearing to a greater or less degree in every substance. He showed that the power of diffusion through liquids depends very much on these fundamental differences of condition,-sugar, one of the least diffusible of the crystalloids, diffusing fourteen times more rapidly than caromel, the corresponding colloid. He also showed that, in accordance with the general chemical rule, while colloids readily combine with crystalloids, bodies in the same condition manifest little or no tendency to chemical union. Hence in osmose, where the membranes employed are invariably colloidal, the osmotic action is confined almost entirely to crystalloids, since they alone are capable of entering into that combination with the material of the septum on which the whole action depends.

On the above principles Graham based a simple method of separating crystalloids from colloids, which he called "dialysis,"

and which was a most valuable addition to the means of chemical analysis. A shallow tray, prepared by stretching parchment paper (an insoluble colloid) over a gutta-percha hoop, is the only apparatus required. The solution to be "dialyzed" is poured into this tray, which is then floated on pure water, whose volume should be eight or ten times greater than that of the solution. Under these conditions the crystalloids will diffuse through the porous septum into the water, leaving the colloids on the tray, and in the course of a few days a more or less complete separation of the two classes of bodies will have taken place. In this way arsenious acid and similar crystalloids may be separated from the colloidal materials with which, in the case of poisoning, they are usually found mixed in the animal juices or

tissues.

But besides having these practical applications, the method of dialysis in the hands of Graham yielded the most startling results, developing an almost entirely new class of bodies as the colloidal forms of our most familiar substances, and justifying

the conclusion that the colloidal as well as the crystalline condition is an almost universal attribute of matter. Thus, he was able to obtain solutions in water of the colloidal states of aluminic, ferric, chromic, stannic, metastannic, titannic, molybdic, tungstic, and silicic hydrates, all of which gelatinize under definite conditions like a solution of glue. The wonderful nature of these facts can be thoroughly appreciated only by those familiar with the subject, but all may understand the surprise with which the chemist saw such hard, insoluble bodies as flint dissolved abundantly in water and converted into soft jellies. These facts are, without doubt, the most important contributions of Dr. Graham to pure chemistry.

In this sketch of the scientific career of our late Associate, we have followed the logical, rather than the chronological, order of events, hoping thus to render the relations of the different parts of his work more intelligible. It must be remembered, however, that the two lines of investigation we have distinguished were in fact interwoven, and that the beautiful harmony which his completed life presents was the result, not of a preconceived plan but of a constant devotion to truth, and a child-like faith, which unhesitatingly pressed forward whenever nature pointed out the way.

Although the investigations of the phenomena connected with the molecular motion in gases and liquids were by far the most important of Dr. Graham's labors, he also contributed to chemistry many researches which cannot be included under this head. Of these, which we may regard as his detached efforts, the most important was his investigation of the hydrates and other salts of phosphorus. It is true that the interpretation he gave of the results has been materially modified by the modern chemical philosophy, yet the facts which he established form an important part of the basis on which that philosophy rests. Indeed, it seems as if he almost anticipated the later doctrines of types and polybasic acids, and in none of his work did he show more discriminating observation or acute reasoning. A subsequent investigation on the condition of water in several crystalline salts and in the hydrates of sulphuric acid is equally remarkable. Lastly, Graham also made interesting observations on the combination of alcohol with salts, on the process of etherification, on the slow oxidation of phosphorous, and on the spontaneous inflammability of phosphuretted hydrogen. It would not, however, be appropriate in this place to do more than enumerate the subjects of these less important studies; and we have only aimed in this sketch to give a general view of the character of the field which this eminent student of nature chiefly cultivated, and to show how abundant was the harvest of truth which we owe to his faithful toil.

Graham was not a voluminous writer. His scientific papers were all very brief, but comprehensive, and his "Elements of Chemistry" was his only large work. This was an admirable exposition of chemical physics, as well as of pure chemistry, and gave a more philosophical account of the theory of the galvanic battery than had previously appeared. Our late associate was fortunate in receiving during life a generous recogni tion of the value of his labors. His membership was sought by almost all the chief scientific societies of the world, and he enjoyed to a high degree the confidence and esteem of his associates. Indeed, he was singularly elevated above the petty jealousies and belittling quarrels, which so often mar the beauty of a student's life, while the great loveliness and kindliness of his nature closely endeared him to his friends. He was never married, keeping house with a sister at No. 4 Gordon Square, where he dispensed a liberal hospitality, which has been enjoyed by many of our scientific countrymen who have visited London during the last twenty years.

In concluding, we must not forget to mention that most genial trait of Graham's character, his sympathy with young men, which gave him great influence as a teacher in the College with which he was long associated. There are many now prominent in the scientific world who have found in his encouragement the strongest incentive to perseverance, and in his approval and friendship the best reward of success.

ART. XXI-Note on transversely striated muscular fiber among the Gasteropoda; by W. H. DALL.

IN studying the radula of a species of Acmaa (probably A. Borneensis Rve), obtained by Prof. A. S. Bickmore at Amboyna, I noticed, on placing the structure under a power of 100 diameters, that certain of the muscular fibers which adhered to it, when torn from the buccal mass, had a different appearance from the others. On increasing the power to some 800 diameters, it was at once evident that the different aspect of these fasciculi was caused by fine, but clearly defined, transverse striation. Suspecting that it was an optical delusion, caused by a very regular arrangement of the nuclei of the fibres, I subjected the muscle to various tests and to still higher magnifying powers. I also introduced under the same glass, some of the voluntary dorsal muscles of a small crustacean, for comparison. The structure of the ultimate fibers in both appeared to be similar. These seemed to be composed of a homogeneous tube or cylindrical band of translucent matter,

with nuclei interspersed at irregular intervals. In neither was there any appearance of separation into transverse disks, as is seen in the striated muscles of vertebrates. That the striated appearance was not due to contraction and folding of the muscle, was evident upon taking a side view of one of the fibers, when the striae on each side, as well as the intervening elevations, were seen to correspond exactly to each other.

The only perceptible differences between the muscles of the crustacean and the striated muscles of the mollusk, appeared to be that the latter were much more finely striate; the striæ being six to eight times as numerous as in the former, in the same space. No difference between the striated and nonstriated muscles of the Acmaa could be observed, except in the fact of the striation. In both the nuclei were irregularly distributed. The appearance of the striated fibre reminded one of a string of rhombic heads, which bore no relation to the position of the true nuclei. The striated fibers appeared, after a careful dissection of the parts in a number of specimens, to be the retractors of the radula; they were longer and in narrower bands than the non-striated fibers and comparatively much fewer in number. The striation was most evident toward the middle of the fibers and became evanescent toward their extremities.

Lebert and Robin (Müller's Arch. f. Anat. and Phys., 1846, p. 126) state that the primitive muscular fasciculi of invertebrates often have the nuclei and intervening clear spaces "arranged in such regular order that they might, at the first glance, be mistaken for transversely striated muscular fibers. The latter, however, are actually found in one acephalous mollusk, Pecten, (and probably in Lima also), and some annelids," and are constantly present in the voluntary muscles of Crustacea and Insecta. In the further researches of M. Lebert (Annales Sci. Nat., t. xiii, 1850, p. 161), he observes that there is nothing extraordinary in the discovery of transversely striated muscular fiber in Polyzoa (Eschara) by Milne Edwards, and in Actinia by Erdl, since "the further we have pursued the study of the comparative histology of muscular fiber, the more convinced we have become that transversely striated muscular fiber is to be found in a large number of animals of very inferior organization, without regard to their more or less advanced position in the animal kingdom."

Striated muscular fiber has lately been shown to exist in the "tail" or appendix of Appendicularia by Moss (Trans. Lin. Soc., vol. xxvii, p. 300). It was already known to exist in Salpa, (Eschricht, ov. Salperne), in the articulated brachiopoda, (Hancock, Tr. Roy. Soc., 1857, p. 805), and in Pecten, (Lebert, Annales Sci. Nat. 1850, 3rd ser., t. xiii, p. 166; and Wagner,

Lehrb. d. vergleich. Anat., t. ii, p. 470, 1847), as well as in Eschara (Milne Edwards, Annales Sci. Nat., series ii, t. iv, p. 3). I believe, however, that this is the first instance in which it has been shown to exist in the class Gasteropoda; and this, as well as the rarity of such cases among the lower invertebrates, is a sufficient apology for bringing forward such an isolated fact. Other duties have not yet permitted me to determine whether this phenomenon is constant throughout the genus, or whether it does or does not occur among allied genera.

ART. XXII.—Note to Article I, on the Quaternary of the New Haven Region; by J. D. DANA.

As my statement in regard to the essential independence of the Connecticut valley glacier, and others, in the Glacial era may be misunderstood, I would draw attention to the meaning of the words "under the Continental glacier" in the note to page 2,in which it is implied that such glaciers are but the inferior portions of the great Continental glacier. I hold that, while the very large valleys of the land, like those of the Connecticut and Hudson, had great influence in determining the direction of the movement in these valleys, especially that along the axis of each, the whole movement must have been more or less modified by the movement of the great northern ice-mass; and that the counteracting influence of a valley depended not only on its depth and extent, but also on its direction and slope. The smaller transverse valleys caused no modification of the general glacier movement; but large transverse valleys gave to the ice in the middle of the channel their own course almost unmodified: if not when the great ice-mass had its maximum thickness, at least afterward when it had become thinner and had lost some of its motion.

I may allude to one other example, as I believe it is, of a partly independent glacier-that of the St. Lawrence valley; for the scratches on its rocks correspond mainly with its course, the prevailing direction, according to Dr. Dawson, being northeast. It should be said that these scratches are attributed by Dr. Dawson to icebergs in the Glacial era, which are supposed to have moved southwestward up the valley, the land being profoundly submerged for the purpose, so as to allow of a discharge of the ocean over the continent in that direction; and the fact that boulders were transported up the valley is given as evidence in favor of this view. But, as in the case of the AM. JOUR. SCI.-THIRD SERIES, VOL I. No. 2.-FEB., 1871.