in mammalia, birds, amphibia, and fishes, it nearly exhibits the proportion of 5, 4, 3, and 2; but the author himself is of opinion that more numerous experiments are necessary to establish this observation as a law.

Vierordt calculates the total amount of blood by means of multiplying the figure expressing the mean duration of the circulation (T) with that for the amount of blood (V) passing from the heart in every unit of time, the total amount of blood being, according to Vierordt-VT: For man the author found V to be 207 cubic centimetres; T 23, 1 seconds; therefore the total amount of blood, 4782 cubic centimetres-5.06 kilogrammes of the weight of body (63-6 kilogrammes). From a large number of experiments on the duration of circulation and on the average amount of blood, Vierordt arrived at the following inferences:

1. The mean duration of circulation of a species of mammalia is equal to the average time in which the heart completes 26-28 pulsations. 2. The mean proportion of the blood expelled by one ventricular contraction to the total amount of blood is nearly constant in the various families of mammalia. Every systole throws about to of the total amount of blood into the aorta. 3. The average duration of circulation is in proportion to the average duration of a complete ventricular movement (systole and diastole), or in an inverse proportion to the mean frequency of pulsation of the species of animal.

4. The mean durations of circulation of two species of animals are nearly in an inverse proportion to the quantities of blood with which equal portions of the animal are supplied in an equal space of time. In one minute, one kilogramme of body receives the following quantity of blood:-Rabbits, 592 grammes; young goat, 311 grms.; dog, 272 grms.; man, 207 grms.; horse, 152 grms. 5. The mean duration of circulation is shorter in smaller than in larger animals. 6. The mean arterial pressure of blood in two species of mammalia bears a nearly inverse proportion to the mean quantity of blood flowing within an equal space of time through a portion of body of the same weight:

According to this theory, the pressure of blood for man would be 200 millim. hydrg. 7. The mean arterial pressures bear nearly the same proportion as the mean durations of circulation. 8. The velocity of blood within the capillaries is in general proportional to the quantity of blood passing within the same time through portions of body of the same weight. The capillary circulation is therefore more rapid in the smaller than in the larger species of mammalia.

Milne-Edwards gives the diameter of the blood-globules of many species of animals. The author draws, from the comparison of the blood-globules of animals belonging to various classes of vertebrata, the inference that there exists a certain relation between the size of the bloodglobules and the physiological activity, especially the respiratory want of the animal-viz., that the respiratory want is in an inverse proportion to the size of the globules, or that the greater the respiratory want, the smaller the diameter of the globules. This relation is evidently much in harmony with the view that the blood-globules are the bearers of oxygen, as the same weight of smaller globules offers a larger surface than the same weight of larger globules.

Nelson considers the diastole of the heart as the effect of an active movement. He assumes that the heart-muscles, unlike voluntary muscles, are possessed of a double power, that of expansion as well as of contraction (p. 82.) The distension of the ventricles, the author says in another place, "is an active and inherent force." The mechanical forces acting on the movement of the blood in the veins are:-1. That furnished by the heart and arteries; 2. That by the pleural vacuum of the thorax; and 3. The expansive power of the auricle. A fourth, 'possibly physiological," power the author is inclined to assume, from the fact that soon after death the body becomes mottled, even in the elevated parts of the body, while these

parts are left completely white at a later period. Nelson himself does not endeavour to explain the nature of this assumed fourth force. The emptiness of the arteries and their flattening after death is "due to two forces,—a vacuum and an interstitial circulation or movement; and because the pleural vacuum can with difficulty reach through the hepatic system to the mesenteric arteries, they are never found so completely empty as the arteries belonging to the extra digestive system.'

Calliburces has made experiments on the influence of warmth on the action of the heart. He found that the number of pulsations of the heart of a frog is considerably increased by immersing his hind legs into warm water; the same result was obtained after section of the crural nerves, and after poisoning by curare, showing, to the author's mind, that the nerves are not connected with this increased frequency of pulsation. The immersion of a cut out frog's heart into water of 40° Cent. (140° F.) raised the number of contractions from 18 to 94 per minute; in a second case from 38 to 80. Water of 25° C. (77° F.) caused an increase from 30 to 62; water of 50° (122° F.) from 36 to 72. Water of 10° (50° F.) stopped the action of the same heart, while soon afterwards the immersion into water of 50° (122° F.) produced 82 pulsations.

Valentin found that the waking marmot excreted in the average 75 times more carbonic acid, and inhaled 41 times more oxygen than the same animal in the most complete state of hybernation. The stages between waking and most profound hybernation yielded intermediate figures. A waking hedgehog yielded about 20-5 more carbonic acid, and consumed 184 times more oxygen than one in the state of hybernation. The author's observations further show, that the profounder the stage of hybernation the more is the consumption of oxygen in excess to the excretion of carbonic acid. The proportion of carbonic acid excreted to the oxygen consumed was, in the waking state, 1: 090; in the half-sleeping condition, 1:101; in the quiet sleep, 1:1:39; in the profound sleep, 1 : 1·65.

Schnepf's observations on the vital capacity of the lungs are made by Bernard's spirometer. Regarding the influence of age, he found that the capacity is highest in the age of twenty. The greatest increase takes place between the years of fourteen and seventeen. The average increase for every year below the age of ten is about 140 cubic centimetres; the average capacity at the age of ten years being 1400 cubic centimetres; from the tenth to the twentieth year the annual increase is more considerable, amounting in the average to 260 cubic centimetres. For the period of decrease after the age of twenty no certain figure, expressing the annual diminution, can be fixed as yet. The capacity of women is smaller than that of men. With regard to height of body, persons of the same height may exhibit a difference of 1200 or 1300 cubic centimetres. Although the vital capacity in general increases in proportion to the height, yet there are many exceptions, and the age is, according to the author, of greater importance. There does not exist a certain relation between the circumference of the chest and the vital capacity.

IV. ABSORPTION, NUTRITION, AND METAMORPHOSIS OF MATTER; SECRETION AND EXCRETION.

1. HEIDENHAIN: The Ways of Absorption of Fat. (Moleschott's Untersuchungen, vol. iv., p. 251, 1858.)

2. BERNARD: Onthe Mechanism of the Formation of Sugar in the Liver. (Compt. Rend., vol. xliv., p. 578, 1857; and Gaz. Méd., No. 13, 1857.)

3. PELOUZE: On the Glycogenic Matter. (Compt. Rend., vol. xliv., 1857; and Henle and Meissner, 1. c., p. 247.)

4. SANSON: On the Formation of Sugar in the Animal Economy. (Compt. Rend., vol. xliv., pp. 1159 and 1323, and vol. xlv., p. 343, 1857; and Henle and Meissner, 1. c., p. 247.) 5. BERARD: On the Physiological Formation of Sugar in the Animal Economy. (Bull. de l'Acad., vol. xxii., p. 774, 1857; and Schmidt's Jahrb., vol. xcvii., p. l., 1858.)

6. CHAUVEAU: The Substance which in the Blood of Starving Animals reduces the Oxide of Copper, is Fermentable Sugar. (L'Union, 1857, No. 89, p. 366; and Schmidt's Jahrb., . c., p. 1.)

1.

7. FIGUIER: New Facts and Considerations against the Existence of the Sugar-forming Function of the Liver. (Gaz. Hebd., vol. iv., pp. 577 and 608, 1857; and Schmidt's Jahrb., 1. c. p. 1.)

8. SCHIFF: On the Glycogenic Substance in the Liver of Frogs. (Archiv f. Phys. Heilk., 1857, p. 263; and Schmidt's Jahrb., 1. c., p. 1.)

9. LEHMANN: On the Formation of Sugar in the Liver. (Schmidt's Jahrb., vol. xcvii., p. 1, 1858.)

10. Moos: On the Glycogenic Function of the Liver, especially in its Relation to the Nervous System. (Archiv d. Vereins f. wiss. Heilk., vol. iv., p. 38, 1858.)

11. NASSE, H.: On some Differences in the Condition of the Liver of Starving and of Fed Animals. (Archiv d. Vereins f. wiss. Heilk., 1. c., p. 77.)

12. PAVY: 1. On the Alleged Sugar-forming Function of the Liver. 2. The Influence of Diet on the Liver. (Guy's Hosp. Rep., third series, vol. iv., p. 291, 1858.)

13. VALENTIN: Contribution to the Knowledge of Hybernation. (Moleschott's Untersuchungen, vol. ii., p. 1;. vol. iii., p. 195, 1857; and vol. iv., p. 58, 1858.)

STÄDELER: On the Oxidation of Albumin by Hypermanganate of Potash. (Erdmann's Journ., vol. lxii., p. 251; and Canstatt, 1. c., p. 159.)

15. WEISMANN: On the Formation of Hippuric Acid in Man. (Zeitsch. f. rat. Med., third series, vol. ii., p. 331, 1856.)

16. HECKER: Remarks on the so-called Lithic-acid Infarct of Children. (Virch. Archiv, vol. xi., p. 217; and Henle and Meissner, 1. c., p. 339.)

17. KRABBE: On Phosphoric Acid in the Urine. (Kopenhagen, 1857; and Canstatt, l. c., p. 181.)

Heidenhain continued the researches commenced by Brücke, Funke, Köllicker, and others, on the construction of the mucous membrane, and especially the epithelium of the small intestines. Brücke's statement, that the broad surface of the epithelial cells, pointing to the cavity of the tube, is open, is supported. After having injected oil into the stomach of frogs, the author was enabled to recognise on the intestinal mucous membrane, prepared by means of a weak solution of chromic acid, that the epithelial cells and their continuations are provided with continuous hollow channels. From this observation, and similar ones made on fishes, and also, though with more difficulty, on mammalia, Heidenhain concludes :-"That the epithelial cells combined with the cells of the sub-epithelial tissue, which are in an open connexion with the former, offer a system of hollow channels provided with complete walls, which channels serve as pre-existing passages for the fat from the intestinal tube to the chyliferous vessels." The author is inclined to consider his observation as a proof of the correctness of the view of some histologists, that the areolartissue corpuscles are the commencement of the lymphatic vessels (Virchow, Leydig, Friedreich). The subject of the formation of sugar in the liver has occupied, during the last ten years, some of the most able physiologists and physiological chemists. Opposite statements have been made by various observers, and have been repeated within the last two years. The same facts are quoted in support of the opposite views. We purpose giving a short digest of the principal essays on the subject, and commence with the description of the substance discovered by Bernard and Hensen,* as giving rise to the formation of sugar. When pure, this glycogenic substance is a whitish, tasteless, inodorous, neutral, apparently not crystalline powder; it is soluble in water, presenting, when the solution is moderately concentrated, a milky appearance; it is insoluble in alcohol; with iodine it yields a reaction which resembles that of dextrine-viz., it gives rise sometimes to a bluish, sometimes to a violet, a reddishbrown, or a dark blood-red colour; it does not reduce the oxide of copper from an alkaline solution, but it is easily transformed into sugar by ferments, saliva, pancreatic juice, blood, &c. It is, however, important to observe that, although the contact with the saliva at the temperature of about 100°, leads to an almost instantaneous production of sugar, when the solution of the substance is neutral, a small addition of either acid or alkali can interfere with such a result. By Hensen, this body has been called sugar-forming substance, by Bernard glycogenic matter, Pavy proposes the term hepatine, Nasse calls it amylum (Stärkemehl), Schiff is likewise inclined to consider it as animal amylum, and Pelouze's researches show, at all events, the greatest analogy between this substance of the liver and vegetable amylum, quite independently of the great susceptibility of transformation into sugar common to both. By means of fuming nitric acid, Pelouze succeeded in transforming the substance in question into xyloidin, and found for it the formula CH2O2, that for vegetable amylum being C12H10O10- Schiff describes also the microscopical appearance of the liver-amylum, and his statement is corroborated by Nasse. They consider the minute granules found within the liver-cells, besides the nucleus and fat-globules, as representing the sugar-forming substance; they find that the number of granules is largest in the livers yielding most sugar, smallest in those from sickly animals yielding a small amount of sugar; they find the granules altogether wanting in livers of animals perished by starvation, as also in pieces of liver which had been exposed to the influence of saliva.

With regard to the presence or absence of the glycogenic substance in the liver, Bernard found that febrile diseases and other disturbances in the nutrition caused diminution or total disappearance of the substance. Nasse performed a large number of experiments (most of them on rabbits, some on dogs), respecting the influence of food or abstinence, as well on the liver in general as also on the quantity of liver-sugar and sugar-forming substance contained in it. The livers of all the fed animals, their food having consisted in carrots, or in potatoes

* Conf. this Journal, No. 89. 1857.

and hay, yielded much sugar (2·1 per cent.), that of most of the rabbits deprived of food during forty-two to sixty-six hours before death, yielded a very small quantity, but always some; that of those perished from starvation yielded none whatever. The glycogenic substance, too, was wanting in animals subjected to starvation; while amongst the fed animals, the amount was larger in those which had received vegetables rich in sugar mixed with proteinaceous substance, than in those fed on amylaceous food and potatoes. Pavy's experiments on the same subject lead to further results. This author's articles will be reviewed in another section of this Journal; we can, however, not refrain from shortly mentioning the results obtained by him regarding the influence of the quality of food on the amount of glycogenic substance (Pavy's hepatine). The average per-centage of hepatine in the liver of eight dogs kept on animal food was 6.97, in the liver of three dogs kept on vegetable food it was 17-23, in those of four dogs kept on tripe and sugar 14.5. We may reasonably infer, that from sugar and allied substances the extra amount of hepatine was derived in these instances.

Moos, in his researches on the influence of section of the pneumogastric nerves on the amount of sugar yielded by the liver, found that on an average (from 6 cases) 500 grammes of rabbit, after the section of the pneumogastric nerves, yielded 0.1 gramme of liver-sugar; while 500 grammes of healthy rabbit yielded 07 grammes of sugar-i. e., seven times more. The result of the experiments performed on dogs was a similar one. The author, however, is not inclined to attribute to the section of the pneumogastric nerves a direct influence on the sugar-forming substance; but he explains the diminution or disappearance of sugar by the abstinence from food, and the increased metamorphosis of matter after the section of the nerves; a view which is in accordance with the results obtained by Nasse in his experiments on the section of the pneumogastric nerves,* and on the influence of starvation on the liver. In his experiments on the influence of the spinal marrow on the sugar-forming function of the liver, Moos observed that galvanic irritation of the spinal marrow causes diabetes in a shorter time even than the well-known puncture of the medulla oblongata; while section of the spinal marrow causes the speedy disappearance of the sugar, even if the ingestion of food continued. As the vagi do not exercise a direct influence, and the spinal marrow has no other communication with the liver than through the sympathetic nerves, the author considers these as the regulators of the formation of sugar in the liver.

With regard to the influence of hybernation and similar conditions, Valentin found that even after five months' torpidity, the liver of marmots still contained sugar-forming substance; but that the liver of animals perished from exhaustion, during or after hybernation, contained no trace of it. Schiff found, that the liver of frogs contains no sugar in February, that already in January artificial diabetes cannot be effected in them.

Figuier maintains the assertions mentioned in our former reports; his memoirs continue to exhibit, according to Lehmann, the same proofs of chemical inaccuracy as they did before. Sanson endeavours to demonstrate, that all the sugar met with in the system, both of herbivora and carnivora, is derived from the food; that meat, too, contains a large amount of dextrine, that the glycogene or sugar-forming substance is only dextrine in an altered condition. Sanson finds, as well in the venous as in the arterial blood, a substance analogous to dextrine; he considers that the liver only abstracts it from the blood, and stores it up within its tissue. That the blood may contain sugar, the analyses of Bernard himself and of Lehmann sufficiently prove. Nasse, in his last memoir, again communicates observations on the subject; he found sugar in the blood of dogs after amylaceous diet, but did not find it after animal food. The quantity of sugar found by these observers is too small to sustain Sanson's view.

The results of Chauveau's experiments have been mentioned in a contribution to this Journal by Harley; we may, therefore, refer to that memoir.

Bérard found in the thoracic duct of an ox, fed with animal food through a fistula made in the first stomach, a large quantity of sugar. On this and other similar experiments he bases the view, that sugar is constantly formed in all parts of the animal organism, which sugar, by means of the absorbents, is carried to the centre of the circulation; that, however, the digestion adds to this permanent formation of sugar, another intermittent but more active one. The author thinks that not in tubes and hollow channels, but within the substance of the tissues the formation of the sugar takes place. We need scarcely mention, that Bernard would explain the existence of sugar in the thoracic duct as derived from the lymphatics of the liver. With regard to the influence of food or of abstinence on the size and physical condition of the liver, Nasse found, as the mean weight of the liver of fourteen rabbits fed on potatoes, hay, and carrots, 43.53 p. m., the maximum being 55'47 p. m., the minimum 32.6 p. m.; that of sixteen rabbits killed after, in general, forty-two to forty-three hours' starvation, 3512 p. m., the maximum being 43-28 p. m., the minimum 24.8 p. m.; that of six rabbits perished of themselves, after a shorter abstinence, 34.8 p. m., the maximum being 37.8 p. m., the minimum

• Archiv für wissensch. Hellk., vol. ii. 1856; and this Journal, No. 35. 1856.

+ On the Origin and Destruction of Sugar in the Animal Economy, No. 89. 1857

30.0 p. m. If we compare these figures with those found by Valentin, for the liver of the marmot in the beginning and at the end of hybernation, we find for the former condition 33-3 p. m., for the latter 22.5 p. m.

Of Pavy's researches on the influence of various kinds of food, we will only mention, that the mean weight of the liver of eleven dogs, under the influence of animal food, amounted to th part of the entire weight of the animal; that of five dogs kept on vegetable diet to th; that of four dogs kept on animal food mixed with sugar to th of the entire weight.

The liver of starved animals is, according to Nasse's observations, of a brownish red or dirty violet colour, and is always dark-coloured; that of fed animals of a greyish red, and lighter colour, as well on the surface as in the interior; in the former state it is firmer, more tenacious; in the latter softer.

The gall-bladder of the starved animals, in Nasse's experiments, was always quite filled, the bi'e was thick and of green colour; the gall-bladder of the fed animals was almost empty, the bile had the appearance of coloured mucus. Valentin's researches on the hybernation of marmots give for the gall-bladder in the commencement of hybernation a condition analogous to that found in fed animals; at the completion of hybernation, to that found in starved animals.

The just-mentioned essays of Valentin are replete in interest for the study of the phenomena of nutrition and metamorphosis of matter in general. The average loss of 1 kilogramme marmot after about 163 days of hybernation is stated as 351·45 grm. The following table shows how this loss is distributed between the different organs.

We find at once that the brain, the spinal marrow, the eyes, the oesophagus, the colon, and other organs, have a much larger per-centage at the termination than at the beginning of hybernation-i.e., that their proportionate loss is smaller than that of other organs; while the fat (not introduced by the author into the series B), which in the beginning of hybernation amounted to 17 per cent. of the entire weight, had decreased to less than 1th per cent. The gland peculiar to the hybernating mammals exhibits, after the fat, the greatest proportionate loss, sinking from 1:33 per cent. in A, to 0·68 per cent. in B; the liver, too, loses much in proportion, maintaining in B only 2-25 per cent., while it occupies in A 3:33 per cent.

If we compare the results of hybernation with those of starvation, as described by Chossat,* we find that the starving pigeon daily consumes in the average 40 times more muscular substance than the marmot in the state of torpor, and only 11 times more fat, 33 times more of the tissue of the alimentary canal, 18-3 times more liver, 15 times more lung, 5 times more

• Recherches Expérimentales sur l'Inanition. Paris, 1843.