Billeder på siden
PDF
ePub

a

reactions of the opposite side on peripheric irritations. 2. Sections of one half in a greater distance than one line from the origin of the nerves for the limbs below the section, do not exercise a marked influence on the movements of these limbs, nor on their reaction to irritation. 3. Section of either half immediately above the issue of the nerves for the limbs, paralyzes the motion of the corresponding limbs of the same side, but not the reaction to irritation. 4. Longitudinal sections through the median line of the spinal marrow do not impair the motion, but increase the reaction, produced by irritation of parts corresponding to the portion of the spinal marrow thus divided. The author infers from these results, " that a crossed action of the spinal marrow does not exist in frogs.II. In pigeons, section of one lateral half of the spinal marrow, at whatever portion it may be instituted, in no way impairs the voluntary motion of the opposite side of the body, nor the reaction on peripheric irritation; it destroys the voluntary motion of the corresponding side below the place of section, but not the reaction of the same side on irritation, the reaction appears, on the contrary, rather increased. The inference therefore is again, that there is no reason for admitting the view of crossed actions in the spinal marrow of pigeons. III. The experiments on mammalia (rabbits, guinea-pigs, cats, dogs) showed, that section of either lateral half causes paralysis of motion on the corresponding side, below the section, and likewise on the same side increased reaction to irritation; while on the other side of the body neither the voluntary motion nor the reaction to irritation are perceptibly changed. Bezold concludes from this, that there does not exist a crossing of the motor conductors in the spinal marroio of mammalia, and that the crossed transmission of sensi. tive impressions is not proved.

The same author also examined the influence of section of either lateral half of the spinal marrow on the temperature, and found:-1. Constant increase of temperature in the lower part of the leg (or fore-arm), and in the foot of the corresponding side. 2. Constant and considerable decrease of temperature in the lower part of the leg (or fore-arm), and in the foot of the opposite side. These changes began about half an hour after the operation, and increased steadily for some hours to such a degree as sometimes to cause a difference of 15° Cent. (27° Fah.). 3. Decrease of the temperature in general. 4. Constant decrease of temperature (absolute and relative) of the upper part of the arm, of the thigh, and upper part of the leg of the corresponding side. 5. Less considerable diminution in the same parts of the opposite side. 6. Equal diminution on both sides of the thorax, as far as it is covered with the respiratory muscles. Bezold concludes that the vaso-motor nerves of the lower part of the leg and of the foot ascend in the spinal marrow on the same side ир to the medulla oblongata; that a crossing of the vaso-motor nerves for the thigh and upper part of the leg is not proved by the experiments. Finally, the author expresses in the résumé that in none of the classes of animals examined a crossing of the sensitive fibres is proved, nor the converse.

Lister has examined the facts which have induced Ed. Weber, Fflüger, Ludwig, and others to establish the theory of inhibitory nerves. The author's experiments on rabbits corroborate that galvanic irritation of the pneumogastric and splanchnic nerves does produce retardation and quiescence of the movements of the heart and intestines; he thinks himself, however, entitled to infer, from the results of many experiments, that only stronger currents have such an effect, while the mildest currents, "just perceptible to the tip of the tongue,” cause, on the contrary, accelerated contractions of the heart and increased peristaltic movements. With regard to the splanchnic nerves and intestines, Lister sums up as follows: " It appears that the intestines possess an intrinsic ganglionic apparatus which is in all cases essential to the peristaltic movements, and while capable of independent action, is liable to be stimulated or checked by other parts of the nervous system; the inhibiting influence being apparently due to the energetic operation of the same nerve-fibres which, when working more mildly, produce increase of function.” (l. c. p. 372.) Concerning the connexion between the pneumogastric nerves and the heart, the author's view is, likewise, that these nerves have no claim to be called “inhibitory nerves," an expression which he considers “altogether objectionable, since there is good reason to think that the same fibres which check the movements, much more commonly enhance them.” Lister differs, therefore, in his view from Schiff,* who is otherwise a no less energetic opponent to the theory of an “inhibitory system,” and who considers the inhibiting influence as depending on nervous exhaustion. “The very rapid recovery of the intestinal and cardiac actions when the inhibiting galvanic currents are discontinued,” appear to our author incompatible with the explanation by “exhaustion."

We cannot conclude our report on Lister's paper without mentioning that, in repeated experiments, he did not observe increased frequency of the heart's contractions after section of the pneunogastric nerves; a fact which is at variance with the results of other experimenters, of whom we need only mention Nasset and Arnsperger, † who found acceleration of the heart's contractions after section of the vagi.

Pfüger defends the theory of the inhibitory action of the vagi and splanchnici against Schiff's just-mentioned view, by asserting that even the mildest currents cause retardation or quiescence of the respective organs, and by calling to mind that section of the vagi does not produce diminution of the heart's contractions, but, on the contrary, increased frequency. The author further describes Schiff's experiment on the thigh, on which this physiologist principally bases his view, and attempts to show that Schiff has misinterpreted the phenomena ; our space, however, compels us to refer for the description to Pflüger's paper, and to Schiff's "Lehrbuch der Physiologie."

Haber's experiments with curare performed on frogs, ander Reichert's superintendence, corroborate Bernard's and Kölliker's inference, that curare paralyzes the terminations of motor nerves; that the contractions of the muscles, caused by local irritation, after the poisoning by curare, depend on the irritability of the muscular fibres themselves, without the influence of the nerves (see Sub. VI.). The peripheric terminations of the motor nerves first become paralyzed, in general within twelve to fifteen minutes; after five to eight hours the spinal marrow appears paralyzed, while the sensitive nerves in their whole extent, and the trunks of the motor nerves (in opposition to their peripheric termination), retain their irritability for a long period (twenty, thirty-six, or forty-eight hours). The author attributes this difference in the several portions of the nervous system, not to differences in the structure and supply of blood, but to differences in the chemical constitution.

It is well-known that Budge attributes to the part of the spinal marrow situated between the sixth cervical and the third dorsal vertebræ the function of a centre for the cervical portion of the sympathetic nerve (centrum ciliospinale), presiding over the influence of the sympathetic nerve on the movements of the iris and the bloodvessels of the bead (regulation of temperature). The same author establishes a centre for the lumbar portion of the sympathetic nerve (the centrum genito-spinale) situated in rabbits in that part of the spinal marrow which corresponds to the fourth lumbar vertebra. "Budge says that the two filaments of the lumbar portion of the sympathetic nerve are found between the two psoas muscles, behind the aorta and vena cava. Communicating branches are seen passing from one filament to the other, and in the region of the fifth lumbar vertebra a ganglion is constantly met with, which receives communicating branches from the third and fourth lumbar nerves.

Schiff's Lehrbuch der Physiologie. Jahr. 1858. t C nf. this Journal, No. xxxv., p. 234. 1856. Ibid., No. xxxvii., p. 251, 1957.

Galvanic irritation of this ganglion, and of the filaments below it, causes energetic movements of the ductus deferentes, while irritation above the ganglion does not influence them; it also causes increased movement of the urinary bladder, and of the lower part of the rectum. The portion of the spinal marrow which, when irritated, excites the movements of the ductus deferentes, is limited to a length of about three lines; while the centre for the urinary bladder and rectum appears to be rather less limited. If the sympathetic nerve of one side is cut, irritation of the genito-spinal centre causes energetic movements in the deferent duct of the side on which the nerve is entire ; while the movements of the duct of the other side are slight, but not quite absent, on account of the communicating branches between the two nerves. Budge remarks, that these facts, as well as those connected with the cilio-spinal centre, speak against the independence of the sympathetic nervous system.

Wagner had the opportunity of examining the action of the cervical portion of the sympathetic nerve on the eye in the body of a woman who had been beheaded about twenty minutes before the commencement of the experiments. Irritation of the cervical portion of the right sympathetic nerve about 12" below the superior cervical ganglion, by means of a magneto-electric apparatus, caused gradual opening of the lids of the right eye, previously closed; a result which was still obtained forty-five minutes after the decapitation, although then in a less perfect degree. Simultaneous with the opening of the eyelids was the dilatation of the pupil in a very marked manner; an effect which was still obtained, as late as forty-eight minutes after decapitation, when the head was handed over to other experimenters. Wagner adds, that the opening of the eyelids did not depend on the action of the levator palpebræ superioris, as it had quite the character of the action of organic muscular fibres-i.e., the muscular action followed the commencement of the irritation only after some minutes, and continued for some time after the cessation of the irritation.

Eckhard found that the saliva secreted under the influence of irritation of the sympathetic nerve, is different from the fluid obtained through irritation of the glandular branch of the fifth pair. The former is less clear and transparent, and, above all, more thick and viscid than the latter. A more accurate description the author promises on a future occasion.

Pflüger uses the following plan for showing the axis-cylinder. He removes the neurilemma by means of a pin, and spreads out the fibres on the glass slide, without at first adding any fluid. Afterwards he adds a drop of collodion, and covers the whole with a thin glass. Everywhere, the author says, the most distinct axis-cylinders immediately appear.

V. SENSES. KLAATSCH and Stich: On the Seat of Gustative Sensation. (Virchow's

Archiv, vol. xiv., p. 225, 1858.) The greater portion of Klaatsch's and Stich's paper is historical. Their own experiments were made with extract of quassia, solutions of sugar, salt, and tartaric acid. These substances were applied by means of a very thin camel's-hair brush, while the eyes of the person operated upon were tied. The authors infer: “A narrow border round the margin of the tongue, varying from two to four lines in breadth, is subservient to taste; in most persons it lies in the middle of the margin; in some it approaches the upper surface, in very few, it appears, the lower surface. The root and the posterior third of the tongue, as well as a part of the soft palate, are also subservient to taste. Other parts of the mouth or fauces, or of other organs, are not instrumental in this sense.” (l. c., pp. 237, 8.)

9

VI. ORGANS OF LOCOMOTION. 1. HABER : On the Action of Curare on the Cerebro Spinal Nervous System.

(Archiv f. Anat. und Physiol., Jahrgang 1859, p. 98.) 2. Von WITTICH: On Peculiar Muscular Contraction caused by the flowing of

Water through the Vascular System. (Virchow's Archiv, vol. xiii., p. 421, 1858.) Haber bases the view that the contractions of the muscular fibres observed after poisoning by curare (see Sub. V.) are independent of the motor nerves, especially on the character of the muscular contractions, and on the manner of termination of the motor nerves in the tissue of the muscles, as elucidated by Reichert.* This author found that the single fibres of the nerves are spread over a comparatively large space, thus comprising several muscular fibrillæ. “The whole peripheric distribution of the motor nerve-fibres,” he reasons, “the frequent ramifications of the fibres entering the muscle, manifest the principle to bring each nerve-fibre in contact with as many muscular fibres as possible.” From this distribution Reichert inferred, that the irritation, originated by a single nerve-fibre, is not restricted to a limited number of muscular fibres, but acts on the whole muscle, or at least a great portion of it. Experiments show that local irritation of a muscle of an animal recently killed, causes contraction of a considerable number of muscular fibres; while, on the contrary, each local irritation in animals poisoned by curare, causes only a very restricted contraction of fibres, in fact, only of the fibres actually irritated, the other part of the muscle remaining perfectly motionless. It appears from this that the independent irritability of the muscular fibres is at last firmly established.

Wittich studied the nature of the convulsions produced, as E. Weber and Liebig already had observed, by injection of water through the aorta of animals soon after their death. By causing a stream of water to pass through the aorta of frogs, convulsions are occasioned, first in the muscles of the head and neck, then in those of the arms and abdomen, and at last, when the blood is altogether expelled through the veins, also in the posterior limbs. Distilled water caused, of all fluids tried, the most powerful and long-continued con. vulsions; spring and river-water less so; serum and saline solutions bad scarcely any effect. Destruction of the nervous centres and section of the nerves had no influence on the appearance of the convulsions. Frogs poisoned by brucine and curare exhibited, when distilled water was injected, powerful convulsions, while galvanic irritation of the nerves had ceased to excite the muscles. Wittich further convinced himself that distilled water alone, when applied on a frog’s muscle deprived of skin, causes contractions. The author infers that pure water alone, without the influence of the nerves, canses the phenomena in question, and that water is a powerful excitant for the muscles, while it appears to be an indifferent agent with regard to the nerves. The endosmotic interchanges between the tissue of the muscle and the distilled water offer the probable explanation.

a

VII. SEXUAL ORGANS; GENERATION. BERNARD: On a New Function of the Placenta. (Brown-Séquard's Journal,

vol. ii., p. 30, 1859.) Bernard arrived at the following inferences :--1. There exists in the placenta of mammalia a function, hitherto unknown, which coincides with the absence

* C. B. Reichert: Ueber das Verbalten der Nervenfasern bei dem Verlauf, der Vertheilung und Endigung in einem Hautmuskel des Frosches. (Archiv f. Anat, und Phys., Jahrgang 1851, p. 68.

of the glycogenic function of the liver during the first period of the embryonic life. This function is localized in a transitory glandular or epithelial element of the placenta, which in some classes of animals is mixed with the vascular portion of that organ, but which in the ruminantia presents itself in a separated shape, so as form on the amnios spots of epithelial appearance, the glycogenic nature of which has hitherto been unknown. 2. This temporary hepatic organ of the placenta, which permits the study of the formation of the glycogenic substance in an isolated anatomic element, confirms the author's view that the formation of amylaceous matter is a faculty common to the animal and vegetable kingdom. 3. The glycogenic function begins in animals with the commencement of their fætal existence, and before the organ, in which this function is localized in the adult, is developed. The author further proposes the following question—whether the same glandular cells are charged with the double function of producing the glycogenic substance and of forming bile, or whether the liver is to be considered as a compound organ, in which are found mixed two isolated anatomic elements—the one destined to form glycogenic substance, the other to form bile. Bernard thinks that this question may now be decided by researches on the embryonic development and on lower animals. He has himself commenced such researches, and promises to communicate the result.

HALF-YEARLY REPORT ON MATERIA MEDICA AND

THERAPEUTICS.

By ROBERT HUNTER SEMPLE, M.D. Licentiate of the Royal College of Physicians, and Physician to th Northern Dispensary.

I. On the Employment of Tannin in large doses in Albuminous Anasarca. By

Dr. P. GARNIER. (Archives Générales de Médecine, January, 1859.) Although the internal use of tannic acid is still very limited in France, its employment in large doses has been much recommended lately in other countries, and has been extended to numerous cases which, while proving its innoxious character, appear to exhibit it as possessing some totally new properties. It has been shown to be useful in all cases where it is required to arrest hæmor. rhages, to give tone to the organism, or to remedy morbid secretions. It has been employed, for example, with great benefit in albuminuria, diabetes, and serous infiltrations. · From these considerations, Dr. Garnier has been induced to employ tannic acid in the albuminous anasarca consecutive to scarlatina; and he adduces several cases illustrative of this mode of treatment, drawn from his own ex. perience and from cases recorded by other physicians. The cases all prove that in the general serous infiltration of the tissues complicated with albuminous urine, there is a rapid and simultaneous disappearance of these two morbid phenomena under the influence of tannin alone, administered in a large dose. The conclusions drawn by Dr. Garnier are that tannin, employed in doses of two to four grammes a day (zss to 3i), cures anasarca or ædema developed passively and occurring simultaneously with albuminous urine; that its curative action is manifested by abundant urine, gradually resuming its physiological characters, by perspiration, easy alvine evacuations, return of appetite, &c.; that these signs appear from the second day of the administration of the tannin; that given in solution in doses of twenty to fifty centigrammes at a time, tannin causes no unfavourable symptoms affecting the digestive passages; and lastly, that the action of tannin appears to be exerted primarily upon the fluids of 47-XXIV.

16

« ForrigeFortsæt »