New Yurk Wolld's Taris Letter. Hardly hits tho exeiteinont and iioroo incredulity of tho Paris savans respecting the experimenta of Professor Muller, of tVeissnioht, on revivilication, had time to eool, before anothor series of experimenta by the same physiologist, and no loss respectably autheiltioated, startles tho wurlil of scienco. It is nooessary to premiso that the views of physiologists rospecting the mode of activity of tho brain havo recently undergone great modiiicatioii, and tlie oorrectness of the modern ideas is iully supported by the experimenta to whioh wc referí I1.. fornierly imagmed, and is still largely taught, that the activity of the brain depended upon the forcea liberated by certain colla in thu gray matter of that organ, which wero supposed to be thu seat of very active changos demanding an abundant supply of blood. JN'erve-forco was supposed to be set at liborty in these cells, its liberaiion being attended with the production of heat. But these views iiave not been ible to endure the close scrutiny to which the brain has recently Deen subjected. The microsoope bas shown that theso celis, these supposed nerve-force producers, aro only a means of ittterchange of nervous filaments, a provisión tbr tho distribution of telejraph-wires, as it were, not active censors, not batteries liberilting vital furos of any kind. It hap been pmved that iu death frolu starvation, when the stomich has been unablo to receiVe, retain or digest food, while all the rest of the body oses weight, such is not the case with ;he brain substanee proper. In casos of sudden death the muscles have been 'ound producing heat long after life is extinct, while in the braifl'no heat is liberntcd aftcr death) although the brain uiay be gorged with blood, The inl'erence dmwn f rom these faets, as vvell as froui the integrity of the brain in all marmer of disease, is that this organ is 0110 of sluggish nutritiva changos, an inert instrument, played upon by forens A'hieh have thsir origin elsewhere than in the brain matter. Furthormore, iii'vcs and brain substanee, when divided, reunito as -eadily as tendón or skin, or mueous membiancs, and tho ïiervous ihenomena interxupted by the wound or -eciion are re-tstahlUhed when the wound ïas healcd. A!l phyeiologists agree on thispoint. And iis skin or periosteuin, or inucuiis inembrane o,n be transplanted, as BUigeona well know and constantly demónstrate in praotioe, can not nervous tissue be subjuoted to the same prooftss? So reasoiiL'd ouv exjifiiiucnti'r, and these preliminariea will show that Proffessor Muilei's experimeuts were letritimated oy strict scirntiüc reaaoning and resoaroh. Pxofeseor Muller, aftel having 1.:.,planted or transterred the heuiisphores of the biain from ohe animal to anoiher of the Bame species in the higher animáis (ni mimáis, dtfi, cats, &c.) and having irafted the brain so as to produce tho m mi 'es:;itions oí' ccrjbral activity, seciicd at k-iigih the opportunity of perForsiing the same experiment in man, and wit1 : resultswUiob it ia-the object ui ons Jctr to detail. I givo the ïïicts ia reoorded in the Qazette Hettdomadare, tal ,ii trom Viïchoio's ArcMüft, a medical journal published at Berlia, It was at Leipzig that the experiment waa performed. A soldier who had killed the eolonel of his fegiment in cold blood, and whom the soverity of Prussiarl lnilititry discipline would have caused to die a hundrea deuths, had it been possiblo, was deilberatély hsnded over to the surgeons, by sentence of court martial, and was confinei in a strongroom in tbc military hospital, cn'irely in the dark as to the tato which awaited )iim. lío was kept there rendy f'or an emergoncy, which dia not fail to oceur. A keeper of a beercellar in Leipzig, a man resembling in many respeota tho eendeaaned soldier, and who had been seized with ncüte inilaimnation of tho heart, or rather of its in vea t ing mewbrane, was brought to the hospital to die of that incurable and proinptly fatal nialadvi No soonet had the auticipated death taken place than the dead saloon-keeper Wan placed on a tablo by the side of another operaling table, on which was tho chloroformed but living body of the soldier. Tvvo surgeons, with assistante, proceeded alike in both cases, to divide the scalp over tho summit of the skull from car to ear, turli baok the divisions and remove the sknll-cap by incisions passing aronnd the skull like a crown. In the soldier, whose carotid arteiies had been prepared for comprensión, these vessels were clamped, so as to prevent hemorrhagp, and but a few drops of blood were lost duriiig the entire operation- In each the dura mater was incised, and the heiuispheics of the brain were removed by an incisión with a shaip, thin-bladed knife passing above tho bellum, ov a narrow portion of about two monee in diameter called the cura cerebri. The brain of the keeper, whioh was sound, the heart diaease having left it intact, he having been sensible to tlic last, was tr&nsforred to tho skuil of the soldier, by au ingenious contrivanee, fully detailed in the Oi nette, tho continuity of the arterial and venous tubes was established. Tho greatest care was taken in securing the natural adaptation of the parta to a fraction of a line, and the skull, having been Teplaced simply, was beid down and in position by the scalp, whieh was drawn over, and itsedgesconflned by strips of adhesiva piaster, and over all was placed a bandnge. It was not until several days had passed that ftie pressure upoti tho carotid arteries was entirely relaxed, although before the skull was replaeed the flow of blood in the vessels of the brain was proved to be reslored. The chiof fear was frons the results of inflammation and suppivration, but fortunately noithor onsued, and the wounded parta healod kindly. There was from the first no difficulty in feeding tlio patiënt, nor wo.s difficulty anticipated, tor it is well known that in puppies and kitten8 in whieh tho entiro bram bas boen removed, sucking and swallowing go on as well as beforo the operation, and in this caso the nerves which preside over deglutition and digestión were far below the point of suction. The patiënt remained in a sound sleep for two weeks, as in a caso of apoplexy, the circulation, digestión and all the vegetative functions of lifü being unintorrupted. Tho gradual unión of the parts was shown by faint but gradually increasiiiE; movenient of the limbs, of the jaws and of tho muscles of' expression in the faca. Speech did not f, possiblo until the close of the thiril week, and then it was hesitating, stammenng as a ehild learns. Although it wa3 evident that the patiënt tried to utter words and sentences, it was vcry gradually that the power of intelligible articulation returned. ïho GazetU contains the report, in a tabular torra, of the inercasing voluntary power over the anus and hands, as measured trom day to day by tho dynamomater, tho measurements given in kilogranimes : also, the daily tuniperature of the limbs, as shown by the thermometer in eea of centígrada i also tbe return ing sensibility of the 'ïngers and lips, as given V;y an iustrumeirt callad BBsthesioinotei' ; but I omit the o as your readers I will be iuturested in tho niain i'aets oulj. Whcn speech became intelligiblo it was found that the soldier, as he eemed, luid forgott.cn ontiroly his military training and discipline ; on the other hand, he told at a formal examirmtion, in the prHsence of #itriesste, the prioes of all thö wines and beers, such ns the saloon-keep er had beun in tho habit of buying and solliur, uianifesting tho imimpaired cerebral activity of the bitter. Sis memory rècalled the naloon-koeper's telativee, friends and cüstomers, whom he called ly name. The soldier had been ugly, taeiturn, revengeful; he now had the saloonkeepei'H franknefca and even garrulity, in spite of his stanimering utterance. Ha wa.s totally blind ; although tho i of smell and sight had been appi'oxinir.ted in the openition but feiled to unite, It was both sad and straugo to sec and hear the soldier groping in his inflrmity of blindncss and giving proof of all tho patiënt enduranco and goounoss of haart whioh had made the saloon keeper dc[IJr eteénied and prosperous. ïhese are the mam l'acts in tho caso ns far as detailel in the Archive, but the subject of experiment preïents so ïuany important problems of tho rclation betwecn blood and brain, of hoart-power aud nervous energy, that we may be well assured that no facts of interest in the ohangeii condition of tho culprit vill bo pc'.uitted to escax notico and record.