562 



PHYSIOLOGY. 



was able to show that from thirty to forty 

 " areas " or centers could be mapped out in accord- 

 ance with their times and rates of development. 

 Important confirmation of the same had come 

 from the researches of Schiiffer, of Budapest, and 

 Storch, of Breslau, on general paralysis. Much 

 attention had been devoted to the study of tendon 

 reflexes, the most important and valuable dis- 

 covery in this direction being the so-called Babin- 

 ski reflex, which is now accepted as a definite in- 

 dication of degeneration of the pyramidal tract. 

 The subjects of toxemia and of internal secretion 

 were receiving more attention, and further inves- 

 tigations in these directions were needed to eluci- 

 date the pathology of exophthalmic goitre, acro- 

 megaly, and allied'disorders. Quite recently, Prof. 

 Mills, of Philadelphia, had shown that the Ront- 

 gen rays were of use in determining the site and 

 occurrence of certain cerebral tumors. Dr. Henry 

 Head had published a suggestive report upon 

 visceral diseases and the mental changes accom- 

 panying them, and there was still great room for 

 the further elucidation of such neuroses as hyste- 

 ria, neurasthenia, and hypochondriasis, in which 

 mental diseases coexist. On the whole there had 

 been more than usual activity in the realm of 

 neurology; and questions of vastest importance 

 were still awaiting solution. 



An important research has been published by 

 Prof. Karl Schsiffer, of Budapest, on the Topog- 

 raphy of the Cortical Degeneration in General 

 Paralysis of the Insane. The author regards his 

 observations as tending to support Flechsig's As- 

 sociation Centers of the Brain, and concludes that 

 the morbid process (degeneration of medullated 

 nerve-fibers) affects chiefly those centers, viz.: 

 those in the prefrontal, parietal, insular, and 

 supracallosal regions of the hemisphere. " The 

 cortical degeneration in general paralysis is not 

 an irregular, diffuse process, but, on the contrary, 

 a regular, localized, selective, morbid affection 

 of the cortex." 



At the suggestion of Prof. Halliburton, a re- 

 search was undertaken by R. H. C. Gumpertz into 

 the specific gravity of the brain. It had espe- 

 cially in view the statement made by Sir James 

 Crichton Browne " that he had found the specific 

 gravity of the female brain less than that of the 

 male brain, the difference being in the gray mat- 

 ter. The most complete previous research on the 

 subject appeared to be that of Danilewsky, who 

 found the specific gravity of the brain to be 1.038; 

 that of the gray matter, 1.033; and that of the 

 white matter, 1.041 ; and the average thickness 

 of the gray matter, 2.5 millimeters. The author, 

 experimenting upon a larger number of cases of 

 healthy men and women who had suffered from 

 no brain disorder, found as the average specific 

 gravities in the respective parts of the brains of 

 seven men frontal, 1.0352; Rolandic, 1.0365; oc- 

 cipital, 1.0356; the whole brain, 1.0361 ; and in six 

 women frontal, 1.0360; Rolandic, 1.0368; occipi- 

 tal, 1.0365; the whole brain, 1.0364. These results 

 are somewhat lower than those given by Dani- 

 lewsky; they show considerable variations be- 

 tween the specific gravities of different parts of 

 the same brain and of different brains in both 

 sexes; and indicate that the average specific grav- 

 ity is practically identical in both sexes. A low 

 specific gravity of brain does not imply poor qual- 

 ity, for the part which is most important and 

 most active the gray matter has a lower spe- 

 cific gravity than the white matter. 



Specimens exhibited to the British Association 

 by Dr. John Turner in illustration of a paper on 

 some new features in the intimate structure of 

 the human cerebral cortex showed: 1, A beaded 



network enveloping the pyramidal cells of the cor- 

 tex and the dendrites; and 2, an intercellular plex- 

 us of the nerve-fibers not previously demonstrated 

 to exist. The preparations demonstrating these 

 points had been made by placing pieces of the 

 brain tissue directly on removal from the body, 

 and without previous hardening or fixing, into a 

 strong solution containing methylene blue and 

 hydrogen peroxid. From this mixture, after a 

 sufficient time had elapsed, the tissue was trans- 

 ferred to a solution of molybdate of ammonia. 

 The tissue was then, after this fixation, dehy- 

 drated, embedded in paraffin, and cut into sec- 

 tions. The beaded network was a network, not of 

 neurological fibers, but of processes of true nerve- 

 cells. It loosely invested the pyramidal cells and 

 their dendrites. It was made up of the fiber ram- 

 ifications of stouter fibers which could be traced 

 from certain pyriform dark cells in the cerebral 

 cortex. The cells were generally small, and ex- 

 hibited no signs of any network around them. 

 There seemed, in fact, to be in the cortex of the 

 cerebrum at least two systems of nerve-cells the 

 pyramidal variety, which were pale under the 

 method of examination employed in the experi- 

 ments, and the smaller darkly stained pyriform 

 nerve-cells. The latter possessed branches which 

 ramified and produced by a fusion a true net- 

 work formed by actual anastomosis. The system 

 of dark cells constituted a continuum. 



The hypophysis cerebri is described by E. von 

 Cyon in Pfliiger's Archiv as having a double func- 

 tion.; it controls intracranial blood-pressure and 

 regulates metabolism. The former function is 

 affected mechanically by the circumstance that 

 every increase of blood pressure in the brain con- 

 stitutes a stimulus to the hypophysis and is fol- 

 lowed by an increase in the strength and a slow- 

 ing of the cardiac beats with a slight rise of ex- 

 tracranial pressure. Those rarer and stronger 

 beats of the heart which Cyon names " action 

 pulse," augment the rapidity of the venous blood 

 current, especially in the veins of the thyroid 

 body, and thus remove from the brain the abnor- 

 mal quantity of blood. There is reason to believe 

 that the same effect is in part due chemically to 

 the production of substances which are probably 

 two in number, one of which excites vagal cen- 

 ters, while the second excites the accelera- 

 tors. The action-beats caused by these coinci- 

 dent and harmoniously acting antagonistic agents 

 are highly favorable to the rapidity of the venous 

 blood-current. The influence exerted by the hy- 

 pophysis and its secretions on metabolism is also 

 probably effected by their action on the vagi and 

 the sympathetic nerves, and is indicated by in- 

 creased circulation and a diminution of the body 

 weight. Persistent stimulation of the hypophysis, 

 especially by electric currents, is followed, as a 

 secondary effect, by violent epileptiform convul- 

 sions, which are most easily explained by regard- 

 ing them as disturbances of the circulation in cer- 

 tain parts of the brain. A great increase in the 

 secretion of urine is observed in all cases of stimu- 

 lation of the hvpophysis. 



Prof. W. C/ Halliburton and Dr. T. W. Mott 

 introduce a paper on the regeneration of nerves 

 by referring to two opinions prevailing on the 

 subject: one that the new nerve-fibers sprout out 

 from the central stump of the divided nerve: the 

 other that they are of peripheral origin. Those 

 who held the latter view relied on nistological 

 evidence. But a strand of cells that looks like 

 nerve-fiber might not be physiologically nerve- 

 fiber, inasmuch as it might not be capable of be- 

 ing excited as true nerve-fiber is, or of conducting 

 nerve-impulses as a nerve-fiber can do. These 





