544 



PHYSIOLOGY. 



sented in the brains of those lower animals that 

 have no functional pallium. 



In a paper in the British Association on the 

 return of voluntary movements after alteration 

 of nerve supply by nerve crossing or anastomosis, 

 Dr. Kennedy, of Glasgow, said that his experi- 

 ments on animals had shown that when the 

 nerves supplying the flexor muscles of a limb were 

 divided and cross-united to the nerves supplying 

 the extensor muscles, the animal in time regained 

 the functional use of the limb, although the^ in- 

 nervation of the muscle group was reversed. The 

 principle of nerve crossing found a practical appli- 

 cation in many cases of paralysis of a muscle or 

 group of muscles supplied by a particular nerve. 



Prof. Langendorlt' reported to the Interna- 

 tional Physiological Congress in Turin upon a 

 restoration of function which had occurred one 

 hundred and five days after total extirpation of 

 the superior cervical ganglion of the cat. The 

 signs of paralysis in the eye had then nearly 

 passed off'; they returned at once on section of 

 the sympathetic nerve in the neck. Electrical ex- 

 citation of the upper end of the cut nerve trunk 

 gave strong dilatation of the pupil and the pal- 

 pebral fissure and retraction of the membrana 

 nictitans. Microscopical examination failed to re- 

 veal any reappearance or regeneration of the gan- 

 glion, but the sympathetic fibers must have found 

 their way to their appropriate end-stations. 



It is maintained by Prof. Wedenski, of St. 

 Petersburg, that all general excitants of nerve 

 exhibit three successive phases of influence, viz., 

 a phase in which the rhythm of the excitation 

 exhibits modification in the rhythm of the re- 

 sponse; a phase in which there is a depression of 

 conductivity of the excited state; and a phase of 

 depression of all response to excitation. The au- 

 thor supposes a fundamental similarity of inhibi- 

 tion to necrosis of nerve. 



Experiments made by Prof. Vitzou, of Bucha- 

 rest, to test the supposed inexcitability of the gray 

 matter of the spinal cord to artificial stimuli are 

 regarded by him as demonstrating that the spinal 

 gray matter is excitable by faradic currents. 



Prof. J. N. Langley, of Cambridge, England, re- 

 ported to the International Congress of Physi- 

 ology in Turin concerning his investigations of 

 the group reactions to drugs and blood condi- 

 tions of the different neurons which make up 

 the nerve system. He demonstrated the stimu- 

 lating action of nicotin on the neurons of the 

 superior cervical ganglion in evidence of his 

 view that the drug alters the cell-bodies of 

 that ganglion. Since the suggestion of Carl 

 Huber, of Ann Arbor, it had been customary 

 to suppose that the incidence of the action of 

 nicotin on the sympathetic ganglia lies at the 

 terminal fibrils of the preganglion neurons. The 

 author found that if the preganglion fibers were 

 cut and allowed time for regeneration, the local 

 application of nicotin to the ganglion produced its 

 normal stimulation effect. Applied to a ganglion 

 of the sympathetic chain, nicotin caused erection 

 of hairs only in the region supplied by the gan- 

 glion; if it stimulated the preganglionic nerve- 

 endings, axon-reilexes would move the hairs in 

 other regions. Nicotin probably did not paralyze 

 spinal ganglion cells; it did not stop the passage 

 of impulses through the bipolar cells of the spinal 

 ganglions of the skate. The erection of the hairs 

 of the cat which occurs after asphyxia does not 

 occur if the sympathetic pilomotor nerve-cells 

 have been separated from the spinal cord. This 

 blood stimulant acts, therefore, on the intraspinal 

 pilomotor cells. 



Prof. Langley also spoke, in illustration of the 



same theme, of the effects of suprarenal extract on 

 a number of tissues and organs where he had ex- 

 amined its action. His new results, together 

 with those previously ascertained, showed that in, 

 all cases the extract produced an effect of the 

 same kind as that produced by stimulation of 

 the sympathetic nerve, and not like that produced 

 by a cranial or sacral autonomic nerve. Notwith- 

 standing this, the action of the extract appeared 

 to be directly upon the tissue, not upon the sym- 

 pathetic nerve-endings; thus it produced pallor 

 and secretion of the submaxillary gland, and this 

 after degeneration of the post-ganglionic fibers of 

 the cervical sympathetic. The inhibitory effect 

 of the vagus upon the cardiac sphincter of the 

 stomach was demonstrated to the meeting. 



from experiments relating to the centripetal 

 and centrifugal medullated nerve-fibers arising in 

 the spinal ganglia of mammals, H. H. Dale finds 

 that there are a few more medullated fibers in the 

 trunk than in the nerve-roots, the excess consist- 

 ing probably of fibers which pass the trunk by 

 way of the gray portion of the ramus communi- 

 cans and end in connection with the vessels or 

 other tissue of the ganglion. 



In studies of the action of anesthetics on the 

 neurons of rabbits and dogs, H. Wright found 

 that ether and chloroform anesthesia cause certain 

 changes in the nerve-cells of both brain and spinal 

 cord. These are slight at first, but become more 

 pronounced as the anesthesia is continued. The 

 Nissl granules lost their affinity for methylene 

 blue, and the cells presented a rarefied or, in 

 extreme cases, a skeleton-like appearance. In rab- 

 bits there also appeared an early and constant 

 moniliform enlargement of the tips and. stems of 

 the chief dendritic extensions of many pyramidal 

 cells, growing in size and spreading along the 

 dendrons toward the cell body as the anesthesia 

 was continued. The changes were regarded as due 

 directly to the influence of the anesthetics. A 

 venous congestion observed also appears to be a 

 secondary phenomenon and is not to be regarded 

 as the cause of changes in nerve-cells. As ether 

 and chloroform are said to circulate in the blood 

 as such, neuronal changes ,are regarded as bio- 

 chemical in nature, and produced by the anes- 

 thetic that reaches them through blood-streams. 

 Whether the facts described occur also in the 

 human subject, it is impossible to say. But the 

 author does not consider that there is any an- 

 alogy between the changes described and the bio- 

 chemical anabolic and katabolic changes that 

 occur in daily life and mark our waking and sleep- 

 ing hours. He regards the action of the nar- 

 cotics here as pathological not intensely so, but 

 remote from physiological processes. These ob- 

 servations were afterward supplemented and ex- 

 tended by additional experiments on dogs, with 

 the twofold object of determining whether a still 

 more prolonged period of anesthesia renders the 

 changes more intense and of ascertaining, by ex- 

 amining the tissues of the animals after the an- 

 esthesia had passed off, whether the pseudo-de/ 

 generative change is permanent. The answer to 

 the first question was affirmative; to the second 

 negative. The results confirmed the previous 

 work, and show that ether and chloroform act 

 directly upon the chromatic substance of the peri- 

 karyon, chemically changing it so that it loses 

 its affinity for anilin dyes. The bio-chemical 

 change was more intense in the later experiments 

 than in the others, because the anesthesia was 

 kept up longer. Indications were found that after 

 a certain period of anesthesia (six hours in the 

 dog) the depression of the neuronal function be- 

 comes more rapidly profound, and there is a limit 



