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tion of the vessels of the skin is capable of be- the conclusion that the chief and not the boring regulated independently of the cerebro-spi- der cells produce pepsin. This is confirmed nal vasomotor centers. It is not clear what is by Dr. Langley's comparison of the pepsin conthe nature of this mechanism, but it seems to tents of the different stomach regions in sevbe adequate to measure out the degree of dila- eral animals. In each case the amount of peptation according to the requirements of the tis- sin found bore no relation to the number of sues, and appears to be the same that is called border cells, but almost always varied directly into action under the application of irritants. with the number of chief cells. It was also The capillary vessels have been shown to be shown that in the different regions of the stomcapable of varying their diameters independ- ach of the rabbit most pepsin is found wbere ently of one another. The conclusion is logic the granules are most numerous. It is now ally derivable that each capillary is capable of very generally accepted that pepsin exists in varying its caliber in accordance with the re the gastric glands partly free and partly comquirements of the tissues which it supplies with bined-i.e., partly as pepsin and partly as pepblood. To this automatic regulation of the sinogen. A series of experiments made with peripheral circulation Professor Ray is in special reference to this point has convinced clined to ascribe a function of great impor Dr. Langley that pepsin, as such, does not extance, both from a physiological and a patho- ist in the living glands, but that in the animals logical point of view; and it appears that it is with which he worked, and probably in all principally, if not exclusively, in connection vertebrates, the gastric glands store up pepsinwith it that the contractility of the capillaries ogen and not pepsin. This is converted by comes into play.

hydrochloric acid into pepsin. As far as our Dr. J. N. Langley, of Trinity College, Cam- knowledge goes, rennet - ferment is found in bridge, has brought the subject of the histolo- greatest quantity where there is most pepsin, gy of the gastric or pepsin-making glands be- and both vary pari passu. Perhaps, suggests fore the Royal Society, in a paper in which he Dr. Langley, the granules of the chief cells may has sought to collate the proofs, from his exper- contain zymogen both of pepsin and of reniments, that the gastric glands in life contain net-ferment, and he offers this as a subject for no ferment, but much zymogen or substance further observation. In all the vertebrates in capable or giving rise to ferment; that by far which the gastric glands have been carefully the greater part of the zymogen can be seen in examined in the living state, it has been found the chief cells in the form of granules; and that those gastric glands which produce most that during digestion the granules are usually ferment store up their zymogen in the form of used up in such a manner as to give rise to an granules. The ferment-forming cells consist outer non-granular and an inner granular zone of a net-work of protoplasm, inclosing a mass in the chief cells. These points, if proved, would of granules. It seems probable, on general establish fundamental resemblances in life-hab- grounds, that the cells should store up other it between the chief cells of the gastric glands antecedent substances besides zymogen, and of mammals, the cells of the gastrio glands of we are not without facts which will tell in the lower vertebrates, and the cells of the pan- favor of this view. In the saliva of many anicreatic gland. It was found that the chief-cell mals ferment is almost or entirely absent, but granules of some mainmals are preserved by mucin and proteids occur. We have some osmic acid, while those of others are not. The proof that mucin arises during secretion from examinations were made chiefly with prepara- the splitting up of an antecedent substance, tions of the former class, and were checked by mucigen, which is stored up in the cell ; in the comparison with glands in the fresh state; they serous salivary glands, and in the lachrymal related to the border cells and the chief cells glands, the occurrence of granules which are of different regions of the stomach. In both used up during secretion, just as are the granthe mouse and the mole, in the hungry state, ules of the pancreas or of the gastric glands, the chief cells are granular throughout; in the makes it extremely probable that in those glands digestive state, the chief cells have an outer some antecedents of the proteids found in the non-granular zone of from one third to one secretion, not the actual proteids of the secrehall of the cell. In the Guinea-pig and the tion, are stored up. Apparently, then, a largo rabbit the chief cells of the latter part of the number of gland-cells have the feature in comgreater curvature show few or no granules; mon that the cell protoplasm forms certain in the median part of the greater curvature the antecedent substances, which Dr. Langley proglands have usually an outer clear zone, which poses shall be called “mesostates," which it diminishes in passing toward the fundus, while stores up, and that are converted, when secrein the fundus and in the adjoining part of the tion takes place, into secretory products. In greater curvature the chief cells are granular the pancreas the chief mesostate is trypsinogen, throughout. During digestion an outer clear in the gastric glands it is pepsinogen, in the zone is formed in the glands of the latter part mucous glands it is inucigen, etc. of the fundus and the fore part of the greater Observations made by Uffelmann on a pacurvature, while the cells of the rest of the tient upon whom gastrotomy had been pergreater curvature lose more or less completely formed, have indicated that no hydrochloric their granules. Heidenhain first announced acid is secreted during the earlier stages of

digestion, although that substance may some an experiment in which the diluted parotid extimes be found in the course of three quarters tract retained but a trace of its amylolytic of an hour or an hour after the ingestion of power when it was warmed for fifteen minutes food. The acid present was always lactic, with one tenth of its bulk of gastric fluid. even when the conversion of albumen into The destructive action of even very dilute peptone, and of starch into dextrine and sugar, acids was found to be extraordinarily rapid. was distinctly taking place. The observations The secretions from the pancreas and intestinal of Cash, made in Ludwig's laboratory, have glands are also capable of dissolving the gasshown that, contrary to the statements usually tric ferments, and owe their power chiefly to given in text-books, fats may be split up in the their alkaline salts. The action of these salts, stomach into the fatty acids and glycerine, as exemplified in sodium carbonate, is decided while an acid, perhaps the lactic, is formed. and rapid. It is auginented when trypsin is also It is a remarkable fact that although after the present, but the effect of trypsin alone is less full digestion of every meal a considerable marked. The rennet ferment is, like pepsin, quantity of peptones must be introduced into destroyed rapidly at the body temperature by the blood, none passes off by the kidneys; yet sodium carbonate, and to some extent by trypif solutions of the peptones be directly in- sin; whence we may conclude that it also loses jected into the blood vessels, from 60 to 70 its ferment power irrecoverably in the small per cent is rapidly eliminated by these organs. intestine. Since trypsin is destroyed both by Îlofmeister, finding peptone abundant in the hydrochloric acid and by pepsin, the adminiswall of the intestine, has arrived at the con tration of pancreatic extract with food in clusion, from his experiments on this point, medical practice to aid digestion is of more that the numerous nuclei and cells which oc than doubtful benefit; for little, if any, trypcupy the meshes of the adenoid tissue of the sin can pass into the duodenum to exercise intestinal mucous membrane fix the peptones, a digestive function there. An extract of the and thus enable them to enter the blood- pancreas rapidly loses its amylolytic power current without the danger of being excreted when warmed with dilute hydrochloric acid, by the kidneys. The white corpuscles, on this more rapidly than does trypsin under similar view, act as carriers of nutritive material to all circumstances, but apparently less rapidly than parts of the body, just as the red corpuscles does the amylolytic ferment of the parotid. act as carriers of oxygen.

Recent researches reported by M. Dufresne During digestion much saliva, gastric juice, throw new light on the relations of ptyalin, and pancreatic juice flow into the alimentary diastase, and the gastric juice. It has been a canaÌ, each secretion bearing with it a con- subject of debate whether the saliva is destroyed siderable quantity of ferment, chiefly either in the gastric juice, or continues in the stomach amylolytic or proteolytic. Very little, how- its action on starch. M. Dufresne's experiever, is known of the fate of these ferments; ments prove that the saliva is paralyzed in pure for the little of them that may be found in the gastric juice, but recovers its action in the fæces and urine makes but a small fraction of mixed gastric juice and in the duodenum, and the whole amount which is received by the is capable of continuing the process of saccha alimentary canal during digestion. Dr. J. M. rification ; while diastase is irrecoverably deLangley has made investigations on this sub- stroyed in hydrochloric solutions or in pure ject, the results of which appear to him to gastric juice, and is profoundly altered after show that the amylolytic ferment secreted by passing into the mixed gastric juice, so that if the salivary glands is destroyed by the hydro- it still dissolves starch it no longer saccharifies chloric acid of the gastric juice, that the pro- it. Ptyalin is recommended as an excellent teolytic and rennet ferments secreted by the re-agent for demonstrating the difference begastric glands are destroyed by the alkaline tween mixed gastric juice, which owes its acidsalts of the pancreatic and intestinal juices, ity to organic acids, and pure gastric juice, the and by trypsin, and that the proteolytic and strength of which is derived from hydrochloric amylolytic ferments secreted by the pancreas acid. are not improbably destroyed in the large in Seegen and Kratschner have brought a few testine by the acids formed there. In experi- new facts to light from their investigations of ments with ptyalin, it was found that a ptyalin the relations of sugar to glycogen in the liver ; containing fluid capable of converting a con- and while they find, in accordance with most siderable amount of starch into sugar in a few other observers, that the amount of sugar inminutes is incapable, after treatinent at 35° O. creases after death, they maintain that this with hydrochloric acid of .04 per cent for seven increase does not take place, as is generally hours, of converting any appreciable amount accepted, at the expense of the glycogen, but of starch into sugar in three hours. As in all of some other substance ; for not only does the the animals examined the fluid in the stomach quantity of sugar present augment, but a larger reddened litmus-paper very much more deeply percentage of glycogen can actually in some than does hydrochloric acid, the conclusion is instances be obtained some hours after the redrawn that the amylolytic ferment of the moval of the liver from the body than instantly saliva is destroyed at any rate by the end of after death. If this be true, and glycogen be gastric digestion; and it was corroborated by the result of a process of disintegration, some

ure.

other compounds must also be present in larger duction of these curves, but the contractions quantities shortly after death. If these can be they indicate are readily distinguished from discovered, and their composition ascertained, those which are proper to this organ and which it may hereafter be possible to trace the source are independent of changes in the blood-pressof the glycogenous and saccharine bodies by a Stimulation either of the central end of process of synthesis.

a cut sensory nerve or of the medulla oblongata The lymphatics of the pancreas have been causes a rapid contraction of the spleen. Stimworked out and illustrated by Dr. and Mrs. ulation of the peripheral ends of both splanchHaggan. Sappey, of the Faculty of Medicine nics and of both vagi causes a rapid contraction. of Paris, has published a work on the morpho. After section of these four nerves, stimulation logical elements of the blood, in which he de- of a sensory nerve still causes a contraction, scribes the red and white corpuscles of each showing that vaso-constrictor influences may division of the animal kingdom, and has illus- pass from the cerebro-spinal centers to the trated them with many engravings. Crystal- spleen by some other route or routes than the lizable forms of albumen have been obtained nerves named. The fact that the section of from the seeds of the pumpkin and from hemp- these principal nerves which convey vasomotor seed, the latter presenting the octahedric and influences from the cerebro-spinal centers to rhombic-dodecahedric forms that had been re the spleen has so little effect on the rhythmic garded as peculiar to hæmoglobin.

contractions and expansions of the organ, seems Professor Charles S. Ray, M. D., has applied to indicate that the latter are regulated and to the investigation of the manner of action maintained by some mechanism contained in and the function of the spleen a method of indi- the spleen itself. rect observation in which he studied the rapid MM. H. Caillet de Poncy and C. Livron, or ity of the circulation through its blood vessels. the Medical School at Marseilles, have found It is fully recognized by physiologists that, that, when poisoning by, arsenic takes place, under normal conditions, à certain relation the phosphorus which exists as phosphoric acid subsists between the degree of functional ac in the brain is replaced by arsenic. The subtivity of an organ or tissue and the degree of stitution takes place in the lecithine, a very expansion of its blood vessels. Applying this complex nitrogenized compound, which thus rule to a series of observations on the kidney, becomes transformed into an insoluble albumihe was surprised at the closeness of the corre- noid substance. Acute poisoning takes place spondence that existed between the activity too rapidly for the arseniated lecithine to be with which the renal circulation was carried subjected to physiological reactions and be elimon and the rapidity of the secretion of urine; inated, and the animal dies under the local which was so near that he found the rapidity influence of the poison without sensible variof the flow of urine could be observed indirectly ation of the normal phosphorus of the nervous by watching the changes in the caliber of the matter. In slow and chronic poisoning, the blood vessels of the kidney with much greater replacement is less rapid; arseniated lecithine convenience than could be done directly by is formed and acts as ordinary lecithine, passcounting the number of drops of urine which ing gradually into the insoluble albuminoid escaped. It struck him that this method could state, while the phosphorus is steadily diminbe most usefully applied to the investigation of ished, giving place to the arsenic. organs whose functions can not be studied by Professor Ú. P. Bow ditch and William F. any direct method with which we are as yet Southard, M. D., of the Harvard Medical School, acquainted, of which the spleen is a typical lave performed a conrse of experiments to asexample; and it is conveniently situated for certain which of the two senses, sight and the purpose. His observations taught him that touch, supplies us with the more accurate inthe circulation through the spleen differs from formation as to the position of objects around that of other organs in the important par- us. The comparison may be made in several ticular that the force which impels the blood ways, one of the most obvious of which is to through the organ is not that of the blood- compare the smallest distances within which pressure in the arteries, which has compara- two impressions made upon sensitive surfaces tively little influence on the volume of the can be recognized as separate and distinct. It spleen; but that the splenic circulation is car- has been found, for example, that the distance ried on chiefly, if not exclusively, by a rhtyh- between two luminous points, as two fixed mic contraction of the muscles contained in stars, must subtend a visual angle of at least the capsule and trabecula of the organ. The one minute, in order that the sources of light movement is exceedingly regular, in so far as may be recognized as separate and distinct from rhythm is concerned, and varied but slightly one another. This angle corresponds to a disduring hours of experiment and under consid- tance of 0.00438 millimetre on the retina. The erable changes of position. The process in the smallest distance upon the surface of the body spleen is different in nature from the rhythmic at which two tactile impressions are recognized contraction and expansion which may be ob as distinct is, according to Weber's researches, served in various organs on the “ Traube- 1.1 mm. (upon the tip of the tongue). Hence Hering” blood-pressure curves showing them- it should follow that the retina is 251 times selves. The spleen also takes part in the pro- more accurate than the most sensitive part of

the surface of the body in localizing impressions position of the object was determined by sight, made upon it. It may be objected, however, and in the other half by touch, sight appeared that a comparison of this sort has little value, to be twice as accurate for the determination inasmuch as it is the optical image of the object as touch. The experiments were then varied which is applied to the retina, while the object in different ways, employing indirect instead itself is brought in contact with the surface of of direct vision, to eliminate the aid that might the body. It is interesting, therefore, to coin be given by the muscular sense of the muscles pare the absolute size of the smallest intervals that move the eye; by using the same hand to by which two external objects must be sepa- place the object and to search for it; to deterrated in order that they may make distinct im- mine the effects of different intervals of time; pressions upon the two senses. In making the and to ascertain the effect of maintaining the comparison regard must be had to the distances head in a fixed position. In all, seven sets, of within which both senses can be practically six hundred experiments each, making in all employed. The sense of touch can not be ex- four thousand two hundred trials, were perercised beyond an arm's length, and the sense formed. The result of the whole was, that of sight is useless for objects nearer than the the most accurate spatial knowledge was obnearest point for which the eye can be accom tained by direct vision. The effect of fixing modated. About thirty inches may be assumed the position of the head was to diminish the as the longest convenient range of touch, four accuracy of the localization, but even under inches as the shortest of distinct vision. An those circumstances the errors were, in nearly angle of 1', which has been taken as the mini- every instance, less than those niet with in the mum visual angle, is subtended at the distance other methods of experimenting. The method of four and of thirty inches by lines of 0.03 and next in accuracy was that of localization by 0.2 mm. respectively. That is, two points, 0.03 touch, with the same band by which the movemm. apart, at a distance of four inches from inent in search of the object was executed, the the eye, are seen to be distinct and separate, head being free to move. “It may, at first and the same is true of points 0.2 mm. apart sight,” observe the experimenters, “seem surat thirty inches from the eye. Now, since, ac- prising that this method should be less accucording to Weber, two points, in order to pro- rate than that of direct vision. It would be duce separate impressions upon the skin at the reasonable to suppose that the position of an ends of the fingers, must not be less than 2-2 object having been once determined by the mm. apart, it appears that within the limits of sense of touch, it would be possible to place four and thirty inches the sense of sight is from the hand upon it a second time with greater ten to seventy times more accurate than that of precision than would be possible when the touch. In these tests, however, it is only the position had been determined by the sense of accuracy and delicacy of two sensitive surfaces sight. That the reverse is the case, is probably that are compared together, but in common life to be accounted for by the fact that in our the data of sight and touch are intimately asso- daily life all our movements are guided by the ciated with those of muscular sense; and the sense of sight to a much greater extent than inquiry needs to be continued to ascertain by the sense of touch.” Next in order of acwhether the superiority of vision is main- curacy of localization came the experiments tained under these circumstances. The fact with indirect vision; next, those in which the that we depend more upon touch than upon position of the object was determined by the vision in estimating slight differences of level same hand with which the movement in search in contiguous surfaces, as when we draw the of it was made, but the head was fixed. Least finger-nail over the line of junction, indicates accurate of all the methods employed was that that this may not always be the case.

of touch with the opposite hand. The experiThe experiments of Drs. Bowditch and ments respecting the effects of time showed Southard had especial reference to the de- that a slight interval is required for the formatermination of the relative accuracy of sight tion of a mental image of the object in space, and touch, when aided by the muscular sense, and that this interval is about two seconds, to and were applied for the determination of the wbich point the accuracy of the identifications precision with which a movement can be ex. increased, and after which it diminished. The ecuted toward a point, the position of which results of the experiments, having been obhas been determined by sight or by touch. A tained entirely from one person, are liable to small object was put upon a white sheet of pa- correction for the personal equation; and it is per in different positions. The experimenter, suggested that it would be a very interesting having ascertained its position by sight, shut extension of the research, to inquire how far his eyes and endeavored to touch the object the various occupations of life affect the accurawith the point of a pencil held in his right cy of execution of the movements. "It might, hand. In another set of observations he him- perhaps, be expected that the power of the self put the object in position with the left blind to determine the position of objects by hand, having his eyes closed, and then, keep- the sense of touch would be found, when testing his eyes closed, endeavored to place the ed in this way, to be much greater than that pencil-point upon it as before. In a prelimi- of persons possessed of sight. A few preliminary series of sixty trials, in half of which the nary experiments, however, which bave al

ready been made, seem to indicate that this is No serious drawback was perceived to working not the case."

for four or even six hours consecutively in the M. Ranvier has been much assisted in his air-chamber, till the cutting-edge of the caisson investigations of the structure of the organs of of the east pier was nearly sixty feet below the touch by the examination of the structure of surface of the river. From that time on it infants. At birth, the nerves of touch may be was found best gradually to shorten the workfound to pass into certain papillæ on the palmaring-time and make the rests longer, till the 5th aspect of the fingers, immediately beneath the of February, when a depth of sixty-five feet had cells of the mucous layer of Malpighi, where been reached, and the work-time was made they form a net-work of ramifications which, three watches of two hours each, with twothough distinct, are closely pressed together. hour rests. The first effect noticed upon the No cellular elements are at this time mixed men was a muscular paralysis of the lower with the net-work, but a small collection of limbs, without pain, which would pass off in round cells exists beneath it. These gradually a day or two, but which became more difficult surround the net-work and pass in among its to subdue, more extended and painful, as the branches; the whole soon becomes united, caisson was sunk deeper. It was regarded as and a tactile corpuscle is formed. Sometimes a subject for joking at first, but grew more the corpuscle remains unilobar, but more fre- serious by the middle of February, after which, quently other lobes are formed in the saine the depth being seventy-six feet, severe cases bemanner as the first one, and joined to it. Hence came more frequent. The superintendent of the it is that, in young children, the nerve-fibers work noticed the fact that the sick men were which enter into the composition of the tactile often thinly clad and poorly fed. At the end corpuscles are separated by layers of cells, of March, several persons having died within a which, in the course of development, become few days shortly after coming out of the excavapushed to the periphery of each lobe, and the tions, Dr. A. Jaminet was appointed to take most of them undergo a considerable atrophy. medical charge of the men and establish suitThis fact suggests that they are not nervous in able regulations for their well-being. He had their nature, for the nerve-cells, so far from been a frequent visitor to the air-chamber, had undergoing atrophy during growth, gradually noticed the men as they came out, and had increase in size to their full development. M. observed that their appearance was pallid and Ranvier has not perceived any communication cold, that in some the pulse was quick but between the nerve-fibers and the cells in the somewhat weak, while with others it was as tactile corpuscle; the ramifying branches of the low as sixty; that without exception the worknerve-fibers, after a tortuous and usually com- men complained of fatigue; that the pulse plicated course, end in free, flattened knobs. always quickened on entering the air-chamber,

Wolff has examined the mode in which though it soon fell to the normal rate, and even nerves terminate in muscle, and has arrived at lower; that the number of respirations inthe conclusion that the Doyerian eminences, or creased, and a feeling of exhilaration came on end-plates, are artificial products. The neu- in the air-chamber; and that the workmen rilemma of the nerve passes continuously, he sweated profusely during their stay in it, albelieves, into the sarcolemma of the muscle, though the temperature was often below 60° and the axis cylinder into the muscle-sub- Fahr. The air-lock was, as a rule, excessively stance.

warm when the pressure was increasing, and The duration of muscular contraction in excessively cold when the pressure was dimindifferent muscles of the same animal and in ishing. On the day the caisson touched tho different animals has been made the subject of rock, when the pressure was forty pounds above experiment by Dr. Cash, who has found, in the normal, Dr. Jaminet was conscious of a great agreement with Weber's previous observations, loss of heat and a violent pain in his head, while that some muscles contract under the same in the air-lock on his way out, and afterward stimulus much more rapidly than others, and became partially paralyzed. Among six hunthat temperature exerts a remarkable influ- dred men employed, one hundred and nineence, a dimination of temperature greatly pro- teen cases important enough to need medtracting the duration of the two phases of ical treatment were reported at both piers, pulsation. fIe has also shown that the form fourteen of which died and two were crippled. of the curve presented by each muscle differs Post-mortem examinations were held in the case from that of others; and that in many in- of eight. Dr. Clark, of the City Hospital in stances the tracing is so constant and peculiar St. Louis, believed that the congestion observed as to serve readily to indicate the muscle from was caused by the forcing of the blood in upon which it is derived.

the interior organs of the body in consequence Professor C. M. Woodward, of Washington of the increased atmospheric pressure. Another University, St. Louis, Missouri, has devoted a physician thought the men were poisoned by chapter of his work on the St. Louis Bridge to carbonic acid which had been abnormally rethe review of the affections which the men em ain within the system while in the airployed in sinking the piers for the structure suf- chamber, but which was set free as soon as the fered from compressed air, and of the theories pressure was removed. Dr. Jaminet thought that were proposed to account for the trouble. the affections were due to physical exhaustion

VOL. XXI.-48 A

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