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resembles very closely hydrated starch ; it is neutral, is without odor or taste, produces the sensation of starch on the tongue, and diffuses itself in water, making it strongly opaline. It has no characteristic appearance under the microscope.
Iodine produces with it a color, varying from a dark violet-blue to a clear maroon-red. Heated with soda-lime, it gives, when pure, no ammonia, thus proving the absence of nitrogen. It does not reduce alkaline solutions of copper, does not ferment when mixed with yeast, is entirely insoluble in strong alcohol, and is precipitable from its solutions by basic plumbic acetate. It is changed into dextrin and then into sugar, by all those agents which convert ordinary starch into dextrin and sugar ; prolonged ebullition with dilute mineral acids, and the action of diastase and analogous ferments, such as exist in the pancreatic juice, the saliva, and the blood, effect this change easily; the opaline character of the solution disappears, it is no longer colored by iodine, it reduces alkaline solutions of copper, and ferments with yeast, yielding alcohol and carbonic acid. The diastasic ferments produce this change in a few minutes at the temperature of the body. Torrefaction, and the partial action of ferments or of dilute acids, change the glycogenic matter into a substance which, like dextrin, is insoluble in strong alcohol, is soluble in water giving a transparent solution, is not colored by iodine, does not reduce copper-tests, does not ferment, and rotates to the right the polarized ray. From the above results, Bernard argues that the formation of sugar in animals should be divided into two parts: the 1st entirely vital, since it takes place under the influence of life-consists in the production of the glycogenic matter in the living hepatic tissue; the 2d, entirely chemical, is the transformation of this into sugar by means of a ferment. This ferment was at first supposed to belong to the liver, but finding that blood effected the change in a marked degree, Bernard referred it to this fluid. During digestion, the circulation is much more active, and the transformation of the glycogenic substance is correspondingly great; in torpid animals like frogs, on the other hand, where the circulation is slow, the sugar disappears from the liver, while the glycogenic substance remains. If these animals be warmed, however, the sugar re-appears, and so on alternately. The condition of the nervous system also affects the transformation of the glycogenic matter. When the spinal cord is cut or wounded near the neck, below the origin of the phrenic nerves, the activity of the hepatic circulation is diminished, and after 4 or 5 hours there is no trace of sugar in the liver, though glycogenic matter is found there. On wounding the cerebro-spinal axis near the fourth ventricle, the phenomena produced are precisely the reverse; the abdominal circulation is accelerated, and the glycogenic matter is so largely transformed that it appears in the urine. The paper closes by comparing the liver to a seed; first, a vital action stores up starch in it; then a chemical one changes this starch into sugar.
(26.) On the 1st of June, Sanson announced to the Academy * the discovery of glycogenic matter in the spleen, the lungs, and the kidneys, as well as in venous, arterial, and portal blood.
(27.) At the next session, FIGUIER † communicated some experiments to prove that washing the liver by Bernard's method for forty minutes did not deprive it of sugar. He therefore pulped a liver and washed it until free from sugar; none re-appeared after 24 hours standing. He then washed á liver by Bernard's method for 17 hours, and on dividing it into two parts, found that one at once reduced •123 grams cuprous oxyd, while after 24 hours, the other half only produced •102 grams. In a third experiment a horse's liver, proved to contain sugar, was washed through the portal vein for 2 hours; on examination, no sugar was found in it, nor did it re-appear after 24 hours. Two other experiments resulted similarly. He expresses the opinion that Bernard's glycogenic matter is only albuminose altered by boiling with potash.
(28.) Some experiments on the conversion of the glycogenic matter into xyloidin, were presented to the Academy June 29, by Eug. PELOUZE. One gram of the pure substance was mixed with concentrated nitric acid ; in a few moments it dissolved, and the whole was then poured into water to precipitate the xyloidin. This, after drying, weighed 1:3 grams, the theoretical quantity. It was very combustible, taking fire at 180° C. When the glycogenic matter was treated with dilute nitric acid and heated, it was converted into oxalic acid. On combustion, it yielded carbon 39:8, hydrogen 6:1, oxygen 54:1 = 100, giving the formula €.1,20; while that of ordinary starch treated with potassic hydrate and dried at 100° C., has the composition €,,,,, Pelouze had examined other organs of the body, but had failed to find glycogenic matter in any but the liver. On treating the lungs of a calf by Bernard's method, a substance was obtained which at first sight resembled it; this substance, however, could not be changed into sugar and was probably modified albumin. Sanson’s results are therefore incorrect.
(29.) In a paper presented at the same session,S SANSON asserts that ptyalin converts the starch of the food into dextrin, which is absorbed by the abdominal venous system, carried into the tissues by the general circulation, and converted into glucose, Animals nourished on meat, therefore, get dextrin from their food, a fact which explains the contradictory statements as to the existence of fermentable matter in the blood. Sanson shows that the action of the blood-ferment on dextrin produces sugar, by taking 500 grams arterial blood from the carotid of a horse, defibrinating it at once by whipping, and allowing it to stand 24 hours; at the end of this time it contains sugar and readily ferments. He maintains that the liver forms neither glycogenic matter nor sugar, but simply uses that carried to it in the blood; more sugar is found there than elsewhere, because the circulation is slower.
* C. R., xliv, 1159. + Ib., p. 1213. # Ib., p. 1321 $ Ib., p. 1323.
(30.) Sanson was immediately followed by BERNARD,* who asserted that this animal starch existed only in the liver. His experiments show that when rabbits are fed on carrots a large quantity of glycogenic matter is found in the liver, but none in any other organ. When the animal is fed on grain, the case is more complicated, as soluble starch colorable by iodine is then carried into the body. In a former memoir, it was stated that starchy matters did not pass into the blood as dextrin; but the process used was imperfect, and later researches have proved the presence of dextrin in both blood and muscles. Sanson has simply confirmed this fact. Two points were then noticed: I. The formation of glycogenic matter in the liver is constant, and is entirely independent of the external supply of dextrin or sugar. The blood of a rabbit fed for 3 or 4 days on wheat or oats contains dextrin; but this is not true with an animal fed on carrots. Moreover on changing the food of the first rabbit, the dextrin disappears. The glycogenic function, on the other hand, is never altered; it persists always, no matter how the food varies. The production of dextrin in the blood by certain aliments, is of course interesting; but only so as an independent fact. The presence of dextrin in the organs of horses fed on oats or other grain, has been confirmed at the Ecole Imperiale at Alfort, in connection with M. Bouley; but no conclusion as to the formation of sugar can be drawn from these accidental results. Nor has dextrin been detected in beef or mutton from the butcher's; which should not be the case were it present. II. A second proof of this function is the fact that it diminishes or disappears under the influence of many morbid conditions. Hence, the livers of hospital cadavers contain no sugar, and the livers of executed criminals must be used for its detection. The same fact is true of animal starch; whenever the animal is sick, none is formed, even when food is taken as usual. Experiments at the veterinary school above mentioned, upon horses who though diseased yet ate well, showed no glycogenic matter in the liver, though sugar formed from the food was found there. A comparative experiment, witnessed by Prof. Schmidt of Dorpat, was made on two vigorous horses; one was healthy, but was to be killed because of an old paralysis of one fore leg, of traumatic origin; the other had had an acute inflammation of the foot-joint for 3 years, also from an injury. Both were fed on hay and oats and ate well, though the second animal had some fever. Three or four hours after eating they were killed. On dissection, digestion appeared to have taken place perfectly; the lacteals were full of chyle, and the urine was alkaline. The livers were removed and at once examined; that of the well horse furnished a strongly opaline decoction, very rich in glycogenic matter, while that of the arthritic animal gave a limpid solution containing not a trace. The flesh of both animals contained dextrin and sugar, from the food. It appears, therefore, that on the one hand, the formation of animal starch in the carnivora takes place upon food entirely free from carbohydrates, and on the other, that it ceases in the diseased herbivora, even with food rich in these substances. Beside the febrile state, all exhausting conditions, such as prolonged suffering, arrest this production; hence, healthy animals must be used for its demonstration. The paper closes with a new method for the preparation of the glycogenic matter. A filtered decoction of the healthy liver is mixed with glacial acetic acid in excess; a whitish precipitate of almost pure animal starch falls, while the albuminoid matters being soluble, remain dissolved. A diseased liver gives no precipitate; nor does the solution from any other organ. If a liver solution be divided into two parts, and acetic acid added to one, a heavy precipitate falls; the other, on the addition of a little saliva, becomes transparent and gives no precipitate. In this way, therefore, the presence of the glycogenic matter may be easily and rapidly recognized.
* C. R., xliv, 1325.
(31.) On the 27th of July, FIGUIER * asserted that the sugar which is contained in portal blood is one of the nonfermentable sugars. By a new process, he had isolated a sugar from the jugular and femoral veins of a dog, identical with that in portal blood; it reduced the copper-tests, was not precipitated by basic plumbic acetate, and was not fermentable until boiled with tío of sulphuric acid. When this sugar remains for a time in the system, it becomes fermentable; hence, kiestein-urine sugar, chyle sugar, and the sugar of eggs, are fermentable. Bernard's sugar, therefore, has its origin in the intestinal canal; and Figuier detected there a sweet substance, not precipitable by basic plumbic acetate and not fermentable. He enumerates three varieties of sugar: lst, that of the intestines, not precipitable or fermentable, does not reduce copper-tests; 2d, that of the portal blood, which reduces copper-tests, and is not directly fermentable, but becomes so on boiling with acid; and 3d, that of the liver and chyle, which reduces copper and ferments directly. He asserts that by the action of a boiling solution of potash upon albumin, a sugar capable of reducing the copper-test is formed. Since as in animal fluids like milk, sugar and the albuminates occur together, they may be mutually dependent.
* C. R., xlv, 132.
(32.) A paper by BONNET, confirming Bernard's results, was read at the same session.* Its conclusions are ; 1st, there is no sugar in the portal blood of animals fed on meat, though the liver and hepatic blood contain it; 2d, sugar is formed in the liver posthumously ; 3d, there is no sugar in the general circulation of animals on a meat diet ; 4th, on starchy food after digestion is completed there is no sugar in portal blood; and 5th, if, as Figuier says, the liver actually converts the portal substance into sugar, this is a true function.
(33.) In a third paper read at this session,† Sanson maintains that glycogenic matter, being intermediate between starch and glucose, must vary in its properties according to the stage of conversion; and that the matter which he obtained from the tissues was true glycogenic matter, as, under the influence of diastase, it was converted into sugar, from the fermentation of which he had obtained several specimens of alcohol. Bernard has confirmed what Pelouze had denied, the existence of dextrin in the blood. If dextrin and salivary diastase both exist in the blood, what more is needed for the production of glucose ?
(34.) In another paper, read Sept. 7th, f he says (1) Pelouze's conversion of the glycogenic matter into xyloidin does not prove it to be starch, since dextrin may be thus converted; (2) his analysis fails of proving it, the formula given being that of glucose ; moreover, starch and dextrin being isomeric, analysis cannot decide between them ; (3) acetic acid precipitates dextrin as well as starch ; (4) the glycogenic matter of the liver is chemically dextrin, like that in the blood of other organs; (5) dextrin is found in the portal blood and in that of the general circulation of animals fed exclusively on meat ; (6) the dextrin in meat is spontaneously converted into sugar, when the meat is cut fine, and exposed to the air for 48 hours; (7) no necessity exists for the assumption of a glycogenic function; (8) Bernard's experiments with carrots are unfortunate, * C. R., xlv, 139.
| Ib., p. 140.
| Ib., p. 343.