glands of the placenta; birds being a class of animals in which the placenta is represented in part by the umbilical membrane, in part by the allantois. May it not be asserted therefore, that like mammals, birds also have a transitory liver; especially since the inverse relation of this organ to the actual liver is also true of them? The liver in birds does not act till the 11th or 12th day of incubation; and precisely at this time the umbilical membrane is replaced by the allantois which contains no glycogenic glands.

*

(50.) A second paper by BERNARD was presented to the Academy on the 14th of April, on the relation of the glycogenic matter to the development of certain foetal tissues before the appearance of the liver function. The object of his researches was to ascertain what particular histological elements are accompanied in their development by glycogenic matter. For this purpose the organs examined were divided into two classes: 1st, the exterior or limiting organs, comprising the cutaneous and mucous tissues; and 2d, the interior or contained organs, including the osseous, muscular, nervous, and glandular tissues. On examination, Bernard found that the first class of tissues, i. e., all exterior epithelial membranes, whether constituting a mucous or a cutaneous surface-contain glycogenic matter at certain periods of foetal life. In the cutaneous surface, this substance is found infiltered into the tissues of the skin, as well as collected in the cellules of the epithelium which covers it. Certain animals, as the pig, show this very clearly; while with the rabbit, the cat, and the calf it is more difficult to recognize. The existence of the glycogenic matter in the skin of a foetus may be demonstrated by scraping it with the blade of a sharp knife, and examining the matters removed under the microscope. Among the histological debris are seen the cellules both containing and surrounded by granular matter which is turned wine-red in color by an acidulated solution of iodine. In this way, the disposition of the glycogenic matter in the skin at all periods of development, may readily be studied. This microscopic evidence has always been confirmed chemically, by making a decoction of the tissue; an opaline solution is thus obtained, which is colored wine-red by iodine, and is precipitated by alcohol and by glacial acetic acid in ex

* C. R., xlviii, 673.

To show to the eye the distribution of the glycogenic matter, Bernard places the entire fœtus in an acidulated alcoholic solution of iodine. The horny extremities, the cutaneous orifices-as the anus and the nasal openings-the eyelids, the ears, and the cornea are most colored. The glycogenic matter in the placenta may also be shown in this way.

AM. JOUR. SCI.-SECOND SERIES, VOL. XLVII, No. 140.-MARCH, 1869.

cess; it is also changed into sugar very readily by the action of acids and ferments, and in a word, possesses all the characters of that obtained from the liver or the placenta. The horny appendages of the skin, too, contain glycogenic cellules, which disappear as development progresses. In the skin itself, the glycogenic matter disappears rapidly; being absent toward the third or fourth month of intra-uterine life, in calves 25 to 30 centimeters long, in which well defined epithelium is present. Even when absent from the cellules, it is found infiltrated into the skin. Mucous surfaces also, at certain stages of development, show glycogenic cellules. With embryo pigs, calves, or lambs 3 to 6 centimeters long, they may be observed in the mouth, tongue, pharynx, stomach, large and small intestine, occurring in the epithelium surrounding the villosities. The mucous surfaces of the air passages, and also of the genito-urinary passages show the same fact. It thus appears that all the exterior limiting surfaces possess during foetal life, before the epithelium is fully developed, a glycogenic evolution. Of serous membranes however, the same cannot be said; no glycogenic matter having been found in the epithelium lining the pleura, the peritoneum or the arachnoid. With regard to the internal or contained tissues, they form a separate group, being with few exceptions, unaccompanied by glycogenic matter during their development. The osseous and nervous systems contain no glycogenic matter at any stage; the brain, the spinal cord, the bones-freed from periosteum-and the cartilages, not only in the human fœtus, but in that of the calf, sheep and rabbit, though examined in many ways and at all periods of growth, gave no result. Muscular tissue however, appears to form an exception, since it contains glycogenic matter; but the arrangement of this matter is different from that just noticed. In the very young embryo of the calf, for example, 2 to 4 centimeters long, embryonic cellules not colorable by iodine are found in the positions soon to be occupied by muscular tissue; a little later, when the foetus is from 15 to 20 centimeters long, and when the histological elements of the muscle appear, the muscular fiber is seen as a tube containing nuclei mixed with a granular matter colored red by iodine; this is best seen in the foetus of the cat. As the fiber develops it soon becomes striated; but the glycogenic matter though lessened in amount is not absent, but seems infiltrated into the tissue. In no case did this glycogenic matter appear organized, nor was it contained in cellules. This substance is also present during the development of the smooth muscles of the heart and of the intestines; in the fiber itself it is sometimes diffi

cult to demonstrate this, but with a decoction of the tissues the reaction is easily obtained. This glycogenic matter remains in the muscular tissue during the entire period of intra-uterine life, and disappears very rapidly after birth by muscular and respiratory action. The glandular system too, contains during foetal life no glycogenic matter; the salivary glands, the pancreas, the glands of Lieberkühn, the spleen, and the lymphatic glands having been examined. One glandular organ, the organ which in after life performs the glycogenic function, must be excepted. Though in its evolution, the liver is not accompanied by glycogenic matter, yet toward the middle of foetal life it becomes histologically developed and acts as a biliary and glycogenic organ. It seems designed therefore, to continue in the adult a foetal function previously performed by other and temporary organs. Glycogenic matter then, plays as important a part in the organic development of the foetus as it performs in the nutritive function in adults. "We know in fact that it ceases to be produced in the liver whenever any morbid condition arrests the nutritive function. The substance then which effects the evolution of the foetal organs continues to be concerned in their nutrition in the adult. This fact establishes a direct connection between organic development and those nutritive phenomena which under various aspects, are only a continuation of it." The phenomena of nutrition in the adult may therefore be elucidated by studying the phenomena of fœtal evolution.

(51.) A paper by ROUGET was presented to the Academy April 18th, calling attention to previous memoirs communicated to the Société de Biologie, in which he had shown that the amylaceous substance in the amnion and placenta is not the product of a peculiar organ and is not contained in special glycogenic cellules, but occurs in the more or less modified epithelial cells of these membranes. Farther researches upon other epitheliums had detected this substance in the epidermic cells of the skin, the soft palate, the tongue, the stomach, and in all the cylindrical cells of the epithelium covering the surface of the large, and the villi of the small intestine. With certain animals, all the intestinal epithelium is filled with amylaceous matter three or four days before birth; though at this time the liver, completely developed for a long period, furnishes this matter abundantly. Finally, finding epithelial cells containing glycogenic matter on the lingual and vaginal mucous membranes even after birth, Rouget concludes that the presence of amylaceous matter in any tissue does not argue a special

* C. R., xlviii, 792.

function, but is simply due to the peculiar constitution of the tissue itself. From these facts it is clear that to the proteic and fatty substances of food, now regarded as the only ones which form animal tissues, must be added amylaceous matters, which form tissues as truly in the animal as in the vegetable kingdom.

(52.) In a letter from SCHIFF, read to the Academy May 2d,* while he agrees with Bernard that a portion of the granulations in the hepatic cellules is animal starch, he claims to have discovered this fact himself in 1856, and to have published it in the Archives de Tübingue for 1857, in a communication dated the 18th of March. Two sorts of granulations surround the nucleus in the hepatic cellules. The first sort are large, have well marked outlines, are almost black in color, soluble in alcohol and ether and become diffluent in acids and alkalies. From 8 to 20 of these are contained in a single cellule. They seem to be fat globules. The second sort are very much smaller, are perfectly rounded, the contour being distinct though pale; they are insoluble in alcohol and ether, take a brownish-yellow color with an acidulated tincture of iodine, and resemble in general the starch of the compositæ, as the dahlia and arnica. They are much more numerous than the others, and were regarded in 1857 as animal starch, for the following reasons: (1) when the liver continues to produce the glycogenic matter, but the ferment fails in the blood so that it is not converted into sugar, the hepatic cellules become enormously distended with this substance; (2) when placed in a liquid containing a ferment, these cellules gradually diminish, while the liquid becomes charged with sugar; the action ceases when the cellules are empty; (3) with batrachians normally, and with mammals and birds, whose liver is saccharine at death, the globules are very numerous; the number however, is less than with batrachians in winter; (4) the number of globules at death is always related to the amount of sugar which the liver can furnish; (5) in passing into sugar, these globules become yellowish drops, soluble in water, insoluble in alcohol; evidently animal dextrin; (6) when in the spring the ferment reappears in the blood of frogs, the globules diminish and the hepatic cellules are filled with these drops, and the liver changes color, passing from dark brown to yellowish or reddish; (7) this change of color takes place at different periods with different species; with Rana esculenta it is very late, the liver not becoming saccharine in Switzerland till the end of May; adults pass through it sooner than young animals, females earlier than males; (8)

* C. R., xlviii, 880.

elevation of temperature alone will not produce the ferment and transform the starch; a large number of frogs were kept for more than six months and no sugar was formed though the hepatic cellules were full of starch; (9) in some cases these globules may be absorbed without producing dextrin or sugar; they appear to suffer a change which gives rise to oxalic acid; (10) the diseased livers of mammals, of birds and of frogs which contain no starch, are much darker than those in which the glycogenic transformation is carried on; (11) during hibernation, both the ferment and the hepatic starch are present, though the latter is diminished in amount; (12) nitrogenous tissues treated with cane sugar and sulphuric acid become yellow and then reddish-purple; since therefore the walls of the hepatic cellules and not their contained globules, are colored by this treatment, the latter do not contain nitrogen. Bernard's glycogenic matter according to Schiff, is not a pre-existant anatomical element, but a product derived from this by the processes employed.

(53.) BERNARD followed this paper by a recapitulation of the dates of his own discoveries.* First, in 1854, he announced the existence of glycogenic matter, under the qualified name "a sort of animal starch," in various foetal mammalian tissues, though the substance itself was not then isolated. At the same time, he compared at length, the part which saccharine and amylaceous matters play in the organic evolution of animal and vegetable tissues, and concluded with the opinion that these substances seemed to enter as an essential condition of development of the tissues of both kingdoms of nature. Second, in 1855, he published an experiment fundamental to the glycogenic theory; showing that when the sugar of a healthy liver was removed by washing, the saccharine substance was renewed; thus proving that the sugar is not formed by the splitting up of certain blood elements, but by a fermentation analogous to that taking place in vegetables. Third, in 1857, the isolation of the glycogenic matter was communicated to the Academy on the 23d of March; and, since these experiments, there for the first time described, are referred to in Schiff's paper of the 18th of March above mentioned, it is evident that his paper was antedated and is actually posterior in date to this. The glycogenic matter was here called amidon animal; and it was shown to be an isomer of vegetable starch, having all its physical, chemical, and physiological properties, changing to dextrin and sugar by acids and ferments, rotating the polarized ray, etc. The existence of the ferment both in the liver-tissue

* C. R, xlviii, 884.