The Nervous System Chapter 7. Action Potential (nerve impulse)
THE ACTION OF TOXINS ON THE CENTRAL NERVOUS SYSTEM.
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565 RED CROSS AND KINDRED WORK IN SWITZERLAND. departments of the respective territories are willing to provide land, and sufficient is said to indicate to those who read between the lines as to the class of man or family who would be likely to benefit by the emigration suggested. The knowledge acquired from Sir Rider Haggard’s report will, however, have to be supple- mented by closer inquiry before any prudent decision can be arrived at by individuals. An interesting discussion conducted by correspondence between Sir Rider Haggard, Mr. Jesse Collings, and Mr. Wilmot Corfield upon the comparative claims of settlement upon the land in Great Britain and oversea will be found included. We are inclined to think that Sir Rider Haggard has the best of the argument so far as it carries us, and that his reasons in favour of emigration, as well as the facts that underlie them, are likely to weigh with many of those who some day may consult his report when making their plans. It is easy to prophesy, as Mr. Collings does, that for these men " there will be no sufficient employment in the industrial world in England," but we would rather wait till war has ceased for six months or even for a year or two before settling in our minds what the demands of industry will be. It is easy, again, to write of " nine-tenths of England that might be cultivated." We have seen similar statements elsewhere of a huge acreage which might be cultivated in Cornwall, a county which in many districts is extremely fertile. It is, how- ever, a different task to enable men to whom agri- culture may be a new pursuit to earn a living where their ancestors, when farming prosperously, failed to " see money " in further reclamation of land. The definite prospect of making a livelihood will be the condition which the prudent will ask for. A healthier life in freer surroundings for themselves and their families will be the attraction that will weigh in the balance when the relative merits of urban and rural industries come to be estimated. THE ACTION OF TOXINS ON THE CENTRAL NERVOUS SYSTEM. AN account of some interesting and important observations on the conveyance of toxins to the central nervous system and of their action there is given in a paper which is published in the August number of the Eàinbupgh Medical JournaZ by Dr. David Orr and Major R. G. Rows, R.A.M.C. As the result of a study of many cases of suppurative and other septic conditions, they found that there takes place a spread of the toxin by means of the lym- phatics of the nerve trunks, and that the poison enters the spinal cord at the site of " origin " of the nerve and attacks the nerve-fibres at the point where they lose their covering of neurilemma. The degeneration can sometimes be traced from the anterior roots into the grey matter, where it termi- nates among the cells. To confirm these observa- tions experiments were made on animals by placing celloidin capsules containing pathogenic organisms in contact with selected nerves, and examining the nerves and central nervous system subsequently. The results corresponded with those seen in human disease. Thus when the sciatic nerve was involved, a degeneration of the exogenous system of fibres in the posterior columns of the cord was induced, beginning, as in the human cases, where the fibres lose their sheaths, and involving the root-entry zone and the collaterals passing into the posterior cornua. If nerves in the cheek were selected, the degeneration passed into the pons and medulla. Hence it seems proved that poisons pass along the lymph-channels of the nerves and exert a direct local action on the cord and medulla, passing round the cord to some extent and entering along with the prolongation of the pia- arachnoid. Other experiments were made to simulate a hsematogenous intoxication by placing the infective capsules in the peritoneal cavity, in which case no direct neuritis of peripheral nerves resulted, the condition resembling an alimentary toxaemia. In these cases there were found a primary degeneration of the myelin sheaths of fibres round the periphery of the cord, oedema of the cord, proliferation of the peri-vascular neuroglia, and dilatation of the vessels with hyaline throm- bosis. In this last the hyaline material first lay along the sides of the vessels, giving rise to a net- work extending from side to side, and finally obliterating the lumen completely. Although in these cases there is apparently a hasmatogenous infection, the observers suggest that the poison also affects the sympathetic nerves, thus exciting the vascular reaction observed. Applying the results to human neurology, it would appear that acute and chronic myelitis are due to infection ascending along the nerve trunks. Dementia paralytica is also to be regarded as a chronic inflammatory disease of lymphogenous origin, and tabes dorsalis is similarly produced. Infantile paralysis falls into the same group, the most striking member of which is seen in Landry’s paralysis. On the other hand, the affections of the cord which are met with in anaemia, Addison’s disease, and so forth, are to be classed as heematogenous, showing no inflammatory lesions. RED CROSS AND KINDRED WORK IN SWITZERLAND. THE recent statement in the press that 50 French nurses are being entertained at Montreux for three weeks as guests of the Swiss Government suggests a review of the various forms of beneficent action in which Switzerland has engaged during the past two years. It will be known to all that Geneva was the home of the Red Cross movement and the birthplace of Henri Dunant, who devoted his life to it. Far from obtaining due personal recogni- tion for his work or material reward, he was for much of the latter part of his life unknown and in want, and only when he was quite a broken- down old man, just maintaining his existence at a nursing home above the Lake of Constance, did any public recognition of his life work come to him in the form of an annuity from the Empress Mother of Russia and of one of the Nobel prizes. The Bernese Comite de Secours aux Prisonniers de Guerre arose in December, 1914, as a branch of the Swiss Red Cross. For almost two years it has sent a constant stream of food and clothing to necessi- tous prisoners in all countries, with special atten- tion to the invaded regions with their dispossessed inhabitants. Up to the beginning of August 150,000 packets have been sent, and the Italian internes in Austria have been the concern of the most recent branch of the work at Lugano. From the beginning of the war Geneva has been the bureau of exchange for information concerning prisoners of war and 2000 or more voluntary workers have been constantly engaged in putting relatives in touch with "missing" soldiers. This means of inter-communication was available long
Transcript of THE ACTION OF TOXINS ON THE CENTRAL NERVOUS SYSTEM.
565RED CROSS AND KINDRED WORK IN SWITZERLAND.
departments of the respective territories are
willing to provide land, and sufficient is saidto indicate to those who read between thelines as to the class of man or family whowould be likely to benefit by the emigrationsuggested. The knowledge acquired from Sir RiderHaggard’s report will, however, have to be supple-mented by closer inquiry before any prudentdecision can be arrived at by individuals. An
interesting discussion conducted by correspondencebetween Sir Rider Haggard, Mr. Jesse Collings,and Mr. Wilmot Corfield upon the comparativeclaims of settlement upon the land in GreatBritain and oversea will be found included. Weare inclined to think that Sir Rider Haggard hasthe best of the argument so far as it carries us, andthat his reasons in favour of emigration, as well asthe facts that underlie them, are likely to weighwith many of those who some day may consulthis report when making their plans. It is easy toprophesy, as Mr. Collings does, that for these men" there will be no sufficient employment in theindustrial world in England," but we would ratherwait till war has ceased for six months or evenfor a year or two before settling in our mindswhat the demands of industry will be. It iseasy, again, to write of " nine-tenths of Englandthat might be cultivated." We have seen similarstatements elsewhere of a huge acreage whichmight be cultivated in Cornwall, a county whichin many districts is extremely fertile. It is, how-ever, a different task to enable men to whom agri-culture may be a new pursuit to earn a living wheretheir ancestors, when farming prosperously, failed to"
see money " in further reclamation of land. Thedefinite prospect of making a livelihood will be thecondition which the prudent will ask for. Ahealthier life in freer surroundings for themselvesand their families will be the attraction that willweigh in the balance when the relative merits ofurban and rural industries come to be estimated.
THE ACTION OF TOXINS ON THE CENTRALNERVOUS SYSTEM.
AN account of some interesting and importantobservations on the conveyance of toxins to thecentral nervous system and of their action there isgiven in a paper which is published in the Augustnumber of the Eàinbupgh Medical JournaZ by Dr.David Orr and Major R. G. Rows, R.A.M.C. As theresult of a study of many cases of suppurative andother septic conditions, they found that there takesplace a spread of the toxin by means of the lym-phatics of the nerve trunks, and that the poisonenters the spinal cord at the site of " origin " of thenerve and attacks the nerve-fibres at the pointwhere they lose their covering of neurilemma.The degeneration can sometimes be traced from theanterior roots into the grey matter, where it termi-nates among the cells. To confirm these observa-tions experiments were made on animals by placingcelloidin capsules containing pathogenic organismsin contact with selected nerves, and examining thenerves and central nervous system subsequently.The results corresponded with those seen in humandisease. Thus when the sciatic nerve was involved,a degeneration of the exogenous system of fibres inthe posterior columns of the cord was induced,beginning, as in the human cases, where the fibreslose their sheaths, and involving the root-entry zoneand the collaterals passing into the posteriorcornua. If nerves in the cheek were selected, the
degeneration passed into the pons and medulla.Hence it seems proved that poisons pass alongthe lymph-channels of the nerves and exerta direct local action on the cord and medulla,passing round the cord to some extent andentering along with the prolongation of the pia-arachnoid. Other experiments were made tosimulate a hsematogenous intoxication by placingthe infective capsules in the peritoneal cavity, inwhich case no direct neuritis of peripheral nervesresulted, the condition resembling an alimentarytoxaemia. In these cases there were found a
primary degeneration of the myelin sheaths offibres round the periphery of the cord, oedema ofthe cord, proliferation of the peri-vascular neuroglia,and dilatation of the vessels with hyaline throm-bosis. In this last the hyaline material first layalong the sides of the vessels, giving rise to a net-work extending from side to side, and finallyobliterating the lumen completely. Although inthese cases there is apparently a hasmatogenousinfection, the observers suggest that the poison alsoaffects the sympathetic nerves, thus exciting thevascular reaction observed. Applying the resultsto human neurology, it would appear that acuteand chronic myelitis are due to infection ascendingalong the nerve trunks. Dementia paralytica isalso to be regarded as a chronic inflammatorydisease of lymphogenous origin, and tabes dorsalisis similarly produced. Infantile paralysis falls intothe same group, the most striking member of whichis seen in Landry’s paralysis. On the other hand,the affections of the cord which are met with inanaemia, Addison’s disease, and so forth, are to beclassed as heematogenous, showing no inflammatorylesions.
RED CROSS AND KINDRED WORK INSWITZERLAND.
THE recent statement in the press that 50 Frenchnurses are being entertained at Montreux for threeweeks as guests of the Swiss Government suggestsa review of the various forms of beneficent actionin which Switzerland has engaged during the pasttwo years. It will be known to all that Geneva wasthe home of the Red Cross movement and thebirthplace of Henri Dunant, who devoted his lifeto it. Far from obtaining due personal recogni-tion for his work or material reward, he was formuch of the latter part of his life unknown andin want, and only when he was quite a broken-down old man, just maintaining his existence ata nursing home above the Lake of Constance, didany public recognition of his life work come tohim in the form of an annuity from the EmpressMother of Russia and of one of the Nobel prizes.The Bernese Comite de Secours aux Prisonniers deGuerre arose in December, 1914, as a branch of theSwiss Red Cross. For almost two years it has senta constant stream of food and clothing to necessi-tous prisoners in all countries, with special atten-tion to the invaded regions with their dispossessedinhabitants. Up to the beginning of August150,000 packets have been sent, and the Italianinternes in Austria have been the concern of themost recent branch of the work at Lugano. Fromthe beginning of the war Geneva has been thebureau of exchange for information concerningprisoners of war and 2000 or more voluntaryworkers have been constantly engaged in puttingrelatives in touch with "missing" soldiers. Thismeans of inter-communication was available long
