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purpose and to exert no injurious effect; instantly after death therefore, a strong potash solution was injected into the liver by the portal vein, In this liver no sugar was detected ; though another liver not thus treated, gave in a short time the ordinary sugar-reaction. If one portion of a liver be thus injected, it shows no sugar, while a second portion not thus treated is found to be saccharine. Abstraction of heat from the liver, immediately after death, yields the same result. In one case, a dog was killed, a piece of the liver instantly sliced off and thrown into a freezing mixture of ice and salt; the absence of sugar in this portion was almost complete ; while the rest of the organs, which remained a short time in the animal, afforded 2.96 per cent of sugar. Division of the spinal cord, as already noticed by Bernard, suspends the production of sugar. This fact Pavy explains by showing that the body is thus cooled down so low-to 70°F.—that the post-mortem change does not go on with sufficient rapidity to afford sugar enough for detection. After a longer time, however, the liver becomes strongly saccharine. This view is sustained by the fact that if the temperature of the animal after section of the spinal cord, be artificially maintained, the ordinary amount of sugar is found in the liver; and also by the farther fact that with rabbits whose coats are oiled, so that on exposure to cold their temperature falls, the same result takes place and sugar is no longer found. With frogs, the amount of sugar in the liver is dependent upon their temperature when killed ; a fact noticed by both Pavy and Bernard about the same time. As already stated, Bernard explains this fact by the diminished activity of the abdominal circulation ; Pavy considers that no sugar appears because the post-mortem change is prevented by this diminution of temperature. Hence, Bernard's name, “glycogenic matter,” implies a conversion not physiologically true ; Pavy proposes therefore to call this substance “Hepatine.”

He shows that the amount of hepatine is greater on a vegetable than an animal diet, that it increases when sugar is mixed with the food, and that it causes the liver to vary in relative weight. The liver of 11 dogs fed on meat weighed t's that of the animal, the percentage of hepatine being 6-97; that of five dogs on vegetable food, weighed is that of the animal, and contained 17-23 per cent of hepatine ; while that of four dogs fed on meat and given lb. cane sugar daily, was it that of the animal, the hepatine being 14:5 per cent. What the destination of hepatine is, and by what means it resists transformation during life, are questions which the author leaves for future researches to determine. Possibly some analogy to the latter condition is found in the fact that saliva, which readily converts neutral hepatine into sugar, is entirely without action if it be either acid or alkaline. The trace of sugar (0·047 to 0·073 per cent) found in right ventricular blood, is caused, as Pavy supposes, by the escape of a small amount of hepatine from the liver; since any disturbance in the circulation, either by congestion or otherwise, causes this amount of sugar to increase. Moreover, on artificially introducing hepatine into the blood, this fluid becomes saccharine ; and if sufficient be injected, strongly marked diabetic urine is voided. If an animal be killed, and the circulation be maintained by artificial respiration, the urine becomes strongly saccharine by the sugar produced by the post-mortem transformation of hepatine.

(43.) On the 11th of July, 1859, Bernard presented to the Academy a letter from C. Schmidt of Dorpat communicating the results of his examination of the portal and hepatic blood of three dogs, two of which were digesting meat, the other had fasted for two hours. The portal blood contained no sugar in either case; the hepatic nearly one per cent of the dry residue, for the first two dogs, and about i per cent for the third. Or more exactly, 0.93 and 0.99 for the dogs in digestion, 0:51 per cent for the fasting animal ; thus confirming Lehmann's results.

(44.) In a paper read on the 1st of August, † BERTHELOT and DE LUCA give the results of a research to determine the nature of the glucose yielded by the transformation of Bernard's glycogenic matter. It has never been shown whether this sugar is identical with any of the known varieties, such as grapesugar, malt-sugar, levulose, lactic glucose, etc., or whether it is a new one. Their glucose was obtained by the action of chlorhydric acid upon the glycogenic matter from the liver of a rabbit. They obtained in a well crystallized form, the compound of this glucose and sodic chlorid, and subjected it to a systematic examination. The compound forms bulky crystals, limpid and colorless, capable of reducing the copper-tests, and of fermenting with yeast. They are rhombohedrons of 78°, and their solution rotates to the right +47°, this rotatory power being considerably greater a few minutes after the crystals are dissolved, than subsequently. On analysis they gave 8.3 per cent chlorine, which corresponds to the formula (€ H,, H,O+NaCl. They agree in all their properties with those of the compound of grape-sugar and sodic chlorid, as first described by Peligot and Pasteur. It is therefore certain that hepatic glucose is identical with the ordinary glucose of grapes and of diabetes. * C. R., xlix, 63.

| Ib., p. 213. (To be continued.)

0.), ART. V.-Derivative Hypothesis of Life and Species; by

Professor OWEN, F.R.S.**

$ 422. Biological Questions of 1830.-At the close of my studies at the Jardin des Plantes, Paris, in 1831, I returned strongly moved to lines of research bearing upon the then prevailing phases of thought on some general biological questions.

The great Master in whose dissecting-rooms, as well as in the public galleries of Comparative Anatomy, I was privileged to work, held that 'species were not permanent:' and taught this great and fruitful truth, not doubtfully or hypothetically, but as a fact established inductively on a wide and well-laid basis of observation, by which, indeed, among other acquisitions to science, Comparative Osteology had been created. Campert and Hunterţ suspected that species might be transitory ; but Cuvier, in defining the characters of his Anoplotherium and Palæotherium, &c., proved the fact.

In this truly scientific labor the law of the subordination of the different organic characters to the condition of the whole animal was first appreciated, clearly enunciated, and its application shown to the reconstruction of lost species from fragmentary remains. The importance of this generalization may be paralleled with that of the principle of equivalents in chemical science.

Of the relation of past to present species, and the conditions of their succession, Cuvier had not an adequate basis for a decided opinion. Observation of changes in the relative position of land and sea suggested to him one condition of the advent of new species on an island or continent where old species had died out. This view he illustrates by a hypothetical case of such succession,g but expressly states :-'Je ne prétends pas qu'il ait fallu une création nouvelle pour produire les espèces aujourd'hui existantes, je dis seulement qu'elles n'existoient pas dans les mêmes lieux, et qu'elles ont dû y venir d'ailleurs.'||

Geoffroy Saint-Hilaire, whose discussions with his colleague in the 'Académie des Sciences' made its annals of 1830 memorable, equally rejecting the idea of new creations,* opposed to Cuvier's inductive treatment of the question the following expression of belief :Je ne doute pas que les animaux vivants aujourd'hui ne proviennent, par une suite de générations, et sans interruption, des animaux perdus du monde antédiluvien.'t But with regard to the demonstration of the proposition, of the truth of which he could not entertain a doubt, Geoffroy Saint-Hilaire expressly states :—'Je crois que les temps d'un savoir véritablement satisfaisant en géologie ne sont pas encore venus.'

* As there has been much discussion with regard to the relation of Prof. Owen's views on the origin of species to those of Dr. Darwin, we reprint this chapter (the 40th) from the forthcoming edition of his Anatomy of Vertebrates, from a pamphlet sent us by the author, omitting four of the longer notes.-EDS ť ccxci''.

| CCXCIII'', and other authors cited in cxxxix, p. xlv. & cxxxix, tom. i, p. lxii. (Nos. denoting 'Works' in the 'Lists of Authors cited'in 'Anatomy of Verte

brates,' Vols. I, II, and III.) AM. JOUR. SCI.-SECOND SERIES, VOL. XLVII, No. 139.-Jan., 1869.

| Ib.

The main collateral questions argued in these debates, to some of which I listened, and to all the reports and consequent pamphlets relating thereto devoted intense attention, appeared to me to be the following :

Unity of Plan or Final purpose, as a governing condition of organic development ?

Series of Species, uninterrupted or broken by intervals ?
Extinction, cataclysmal or regulated ?
Development, by epigenesis or evolution ?
Primary life, by miracle or secondary law ?

On returning home and resuming office with additional duties at the Royal College of Surgeons, I was guided in all my work with the hope or endeavor to gain inductive ground for conclusions on these great questions.

§ 423. Homology or Teleology ?-Cuvier held the work of organization to be guided and governed by final purpose, or adaptation, expounding this principle under the terms conditions of existence and correlations of structure.' Geoffroy denied the evidence of design, and protested against the deduction of a purpose as, e. g., from the coexistence of a valve with a definite course of fluid : he contended for the principle which he called 'unité de composition, as the law of organization. Most of his illustrations were open to the demonstration of inaccuracy, and his arguments to the refutation which they received from Cuvier in the debates in question: the logic, and, as it seemed, the facts, were on the side of teleology. The figurative language, moreover, in which contemporary anatomists had expressed their views of a principle akin to Geoffroy's was ill-calculated to enlist supporters. The expressions by which disciples of the school of Schelling illustrated, in the animal structures, the transcendental idea of the repetition of the whole in every part,' operated disadvantageously to the calm inquiry into the prime question, at issue. To Cuvier this language seemed little better than mystical jargon, and he alluded to it with transparent contempt. When he did extend inferences from comparative anatomy beyond the adaptation of structure to function, Cuvier went not beyond a recognition of what I have since termed special homologies :'ť and this lowest degree of correspondence he explained on the ground of the subserviency of such homologous parts to similar ends in different animals ;I viewing them, in fact, in that relation which I express and contrast by the term 'analogies.'s With Cuvier answerable parts occurred in the zoological scale because they had to perform similar functions.

* Or, cette proposition, déja contraire aux plus anciennes données historiques, répugne tout autant aux lumières de la raison naturelle qu'aux spéculations plus réfléchies des sciences physiques.'—CCLXXXVII'', p. 210.

Also, more decisively:--Les animaux perdus sont, par voie non interrompue de générations et de modifications successives, les ancêtres des animaux du monde actuel.'—CCLXXXVII', p. 208.

Most of my fellow-students at the Garden of Plants, in 1830, and some subsequent fellow-laborers, Johannes Müller, Rud. Wagner, Milne-Edwards, Agassiz, implicitly accepted this explanation of the fact of answerable bones and other parts occurring in different species.

After the publication of the 'Memoir on the Pearly Nautilus, and of those on Monotrematous and Marsupial generation, which subjects Cuvier had strongly recommended to my attention, the question of the condition or law of special homologies pressed itself upon me, more especially in connection with the task of arranging and cataloguing the osteological part of the Hunterian Museum.| As my observations and comparisons accumulated, with pari passu tests of observed phenomena of osteogeny, they enforced a reconsideration of Cuvier's conclusions to which I had previously yielded assent. To demonstrate the evidence of the community of organization, I found that the artifice of an archetype vertebrate animal was as essential as that of the archetype plant had been to Goethe in expressing analogous ideas; and as the like reference to an 'ideal type must be to all who undertake to make intelligible the 'unity in variety' pervading any group of organisms. T From the demon

* Quant à M. Oken, il déclare les pièces en question les parties écailleuses des temporaux, ou, selon son langage mystique," la fourchette du membre supérieur de la tête.”—Cet humérous de la tête de M. Oken devient pour M. Spix le pubis de cette même tête; ou, pour parler un langage intelligible, un des osselets de l'ouie, savoir le marteau.'—Cxxxix, tom. v, 2° partie, p. 85.

+ cxl, p. 7.

# Ce n'est qu'un principe subordonné à un autre bien plus élevé et bien plus fécond,à celui des conditions d'existence, de la convenance des parties, de leur coördination pour le rôle que l'animal doit jouer dans la nature. Voilà le vrai principe philosophique d'où découlent la possibilité de certaines ressemblances.'CCXCIV'', p. 9. & cxl, p. 7.

| XLIV. Such ideal type' must not be confounded with the so-called 'types' suppose to be exemplified by certain living species. Arguments against the latter vague and ill-defined ideas are of no weight against the former, and indicate a certain obtuseness of apprehension in the objector. See cccxxvi'', p. 31.

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