THE PECULIARITIES OF SENSIBILITY FOUND IN CUTANEOUS AREAS SUPPLIED BY REGENERATING NERVES
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1271 and to his personal qualities and public services were made by each of the speakers. It is intended that one of these portraits shall hang at the London School of Tropical Medicine and that the other shall remain in the possession of Sir Patrick and Lady Manson and their family. After Sir Patrick Manson had made acknowledgment of the presentation the toast of ’’ the Guests" " was proposed by the chairman and responded to by Sir John Anderson, Permanent Secretary of the Colonial Office, and Dr. Sandwith’s health was proposed in warm terms by Lord Milner, who spoke of his long acquaintance with the chairman since their early days together in Egypt. During the course of the dinner messages of good wishes were exchanged by telegraph between the assembled company and Mr. Joseph Chamberlain, to whom the school is greatly indebted. THE PECULIARITIES OF SENSIBILITY FOUND IN CUTANEOUS AREAS SUPPLIED BY REGENERATING NERVES. UNDER this title Mr. Wilfred Trotter and Mr. H. Morriston 7 Davies, of University College Hospital, have published in the ‘ Journal fiir Psychologie 2cnd Neacrologie (Band XX., 1913, E Erganzungsheft 2) an important communication embodying I the results of researches extending over six years. It will be remembered that in 1905 Dr. Henry Head took a great step in advance, in the study of the difficult problems of cutaneous sensibility in man, by submitting to section of a cutaneous nerve in his own person and by investigation of the changes thereafter produced on his own left forearm and hand. Basing his conclusions on the results obtained by this research, Dr. Head formulated a hypothesis of the function of the peripheral nervous system which was entirely novel and proved to be very illuminating. Dr. Head stated that the peripheral nervous system, on the afferent side, was compact of two subsidiary systems, to which he assigned the terms "protopathic" "and" epicritic respectively. Proto- pathic sensibility was concerned with the appreciation of painful cutaneous stimuli and the extremes of heat and cold. Epicritic sensibility was concerned with cutaneous localisa- tion, the discrimination of two points, and the finer grades of temperature called cool and warm. In view of the extreme importance of the experimental facts established by Dr. Head and the unsatisfactory nature of examinations of ordinary patients, Mr. Trotter and Mr. Davies com- menced a series of similar observations on themselves in 1907. The end they had before them was to obtain as wide a field as possible from which to draw material, and by performing more than one experiment on them- selves to gain knowledge from the phenomena of one which could be used to amplify and coordinate their methods in the next. Accordingly, at intervals during these six years they have divided the following cutaneous nerves in themselves : the internal saphenous, great auricular, internal cutaneous of arm, a branch of the middle cutaneous of thigh. In each instance a piece of the nerve trunk from 5 to 10 mm. in length was excised and the ends united by sutures. It may be remarked parenthetically that the authors found the amount of inconvenience incident on having a divided cutaneous nerve or two extremely small. From the material thus procured,’and as the outcome of a prolonged and rigorous investigation, the authors adduce facts which do not entirely fit in with the theory of Dr. Head, and which, by reason of their cumulative value, are calculated to render the hypothesis of separate epicritic and protopathic systems one the evidence for which is not so unequivocal as may have been supposed. They have found that when a cut nerve is regenerating all forms of sensibility tend to reappear together ; that all returning sensibility is at first hypoæsthetic; and that all i returning sensibility shows the phenomena of I I intensi fica- tion " and of " peripheral reference." By the former term is meant that the sensations elicited by stimuli are intense out of proportion to the stimuli ; by the latter, that when a recovering spot at the proximal end of the anaesthetic area is stimulated, the corresponding sensation, instead of or in addition to being felt locally, is felt at the extreme peripheral end of that area. The important point in these observations is that the authors cannot find any criterion of distinction between the ways in which the various forms of cutaneous sensibility recover, such as Dr. Head found in his one experiment, and on which, to some extent at least, he based his hypothesis of separate physiological systems in the main cutaneous afferent system. There are other facts and other arguments adduced by the authors which need not be further specified, which go to show that the interpretation of the phenomena of regenerating sensi- bility is simpler than that given by Dr. Head. In the mean- time the clinician must be content, we think, to reserve judgment. The exact import of the work here summarised will be seen better when it is put to the test of clinical experience. We consider, however, that Mr. Trotter and Mr. Davies have by this minute and painstaking investigation made no small contribution to the solution of a vexed problem, and have added lustre to the experimental neurology of this country which Dr. Head’s researches have already raised to so high a level. THE PATHOGENESIS OF SYPHILITIC MUSCULAR ATROPHY. AMONG the many minor though none the less fertile dis- cussions at the recent International Congress of Medicine was one on the question of muscular atrophy in tabes and other syphilitic affections. Various opinions as to its patho- genesis have been held : the varying picture presented by the pathological anatomy of these cases is one reason for this absence of unanimity. Tabetic amyotrophy in some casea is the result of ischæmia of the cord from syphilitic disease of the vessels or of the meninges. Sometimes it appears to be the result of a peripheral neuritis ; sometimes there is evidence to suggest a direct action of the syphilitic poison on the nervous parenchyma-i.e., the anterior horn cells. Much light has been thrown upon the syphilitic origin of tabes by the work of Dr. Hideyo Noguchi, who recently gave a demonstration of his results at the Royal Society of Medicine.1 Dr. A. Barre, of Paris, in his con- tribution to the discussion said that in certain cases of tabetic amyotrophy important vascular lesions are present, consisting in subacute or chronic endo- and peri-arteritis and in endo- and peri-phlebitis. It would appear that these lesions have hitherto not had much attention directed to them, but Dr. Barr6 held that some at least of the tabetic amyotrophies are vascular in origin and isohæmic in character, and that from the pathogenic point of view these are closely allied to the other trophic disorders of tabes more frequently met with-viz., arthropathies, perforating ulcers, &c. It is erroneous to regard these trophic changes as tabetic in the strict sense ; the vascular modifications are essentially syphilitic, and whereas some have ascribed a preponderating pathogenic r6le to lesions of the intramuscular nerves, Dr. Barre regarded both these and the actual muscular lesions as secondary to the vessel changes. A second hypothesis which he advanced is, in our opinion, more debatable. He thought that the lesions of the anterior cornual cells not infrequently seen in tabetic atrophy might be secondary to the relative muscular immobility and to the functional weakness which result from such muscular troubles. Dr. Barre regarded the 1 THE LANCET, Oct. 25th, 1913, p. 1187.
Transcript of THE PECULIARITIES OF SENSIBILITY FOUND IN CUTANEOUS AREAS SUPPLIED BY REGENERATING NERVES
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and to his personal qualities and public services were madeby each of the speakers. It is intended that one of these
portraits shall hang at the London School of TropicalMedicine and that the other shall remain in the possessionof Sir Patrick and Lady Manson and their family. After
Sir Patrick Manson had made acknowledgment of the
presentation the toast of ’’ the Guests" " was proposed by thechairman and responded to by Sir John Anderson, PermanentSecretary of the Colonial Office, and Dr. Sandwith’s health
was proposed in warm terms by Lord Milner, who spoke ofhis long acquaintance with the chairman since their earlydays together in Egypt. During the course of the dinnermessages of good wishes were exchanged by telegraphbetween the assembled company and Mr. Joseph Chamberlain,to whom the school is greatly indebted.
THE PECULIARITIES OF SENSIBILITY FOUNDIN CUTANEOUS AREAS SUPPLIED BY
REGENERATING NERVES.
UNDER this title Mr. Wilfred Trotter and Mr. H. Morriston 7Davies, of University College Hospital, have published in the ‘
Journal fiir Psychologie 2cnd Neacrologie (Band XX., 1913, E
Erganzungsheft 2) an important communication embodying Ithe results of researches extending over six years. It will beremembered that in 1905 Dr. Henry Head took a great step inadvance, in the study of the difficult problems of cutaneoussensibility in man, by submitting to section of a cutaneousnerve in his own person and by investigation of the changesthereafter produced on his own left forearm and hand.
Basing his conclusions on the results obtained by this
research, Dr. Head formulated a hypothesis of the functionof the peripheral nervous system which was entirely noveland proved to be very illuminating. Dr. Head stated thatthe peripheral nervous system, on the afferent side, was
compact of two subsidiary systems, to which he assigned theterms "protopathic" "and" epicritic respectively. Proto-
pathic sensibility was concerned with the appreciation of
painful cutaneous stimuli and the extremes of heat and cold.Epicritic sensibility was concerned with cutaneous localisa-tion, the discrimination of two points, and the finer gradesof temperature called cool and warm. In view of theextreme importance of the experimental facts established byDr. Head and the unsatisfactory nature of examinations
of ordinary patients, Mr. Trotter and Mr. Davies com-menced a series of similar observations on themselves in1907. The end they had before them was to obtain
as wide a field as possible from which to draw material,and by performing more than one experiment on them-selves to gain knowledge from the phenomena of onewhich could be used to amplify and coordinate theirmethods in the next. Accordingly, at intervals duringthese six years they have divided the following cutaneousnerves in themselves : the internal saphenous, great auricular,internal cutaneous of arm, a branch of the middle cutaneousof thigh. In each instance a piece of the nerve trunk from5 to 10 mm. in length was excised and the ends united bysutures. It may be remarked parenthetically that the
authors found the amount of inconvenience incident on
having a divided cutaneous nerve or two extremely small.From the material thus procured,’and as the outcome of aprolonged and rigorous investigation, the authors adducefacts which do not entirely fit in with the theory of Dr.Head, and which, by reason of their cumulative value,are calculated to render the hypothesis of separate epicriticand protopathic systems one the evidence for which is
not so unequivocal as may have been supposed. Theyhave found that when a cut nerve is regenerating allforms of sensibility tend to reappear together ; that all
returning sensibility is at first hypoæsthetic; and that all i
returning sensibility shows the phenomena of I I intensi fica-
tion " and of " peripheral reference." By the former term ismeant that the sensations elicited by stimuli are intense
out of proportion to the stimuli ; by the latter, that whena recovering spot at the proximal end of the anaesthetic areais stimulated, the corresponding sensation, instead of or inaddition to being felt locally, is felt at the extreme
peripheral end of that area. The important point in
these observations is that the authors cannot find anycriterion of distinction between the ways in which thevarious forms of cutaneous sensibility recover, such as Dr. Headfound in his one experiment, and on which, to some extentat least, he based his hypothesis of separate physiologicalsystems in the main cutaneous afferent system. There areother facts and other arguments adduced by the authorswhich need not be further specified, which go to show thatthe interpretation of the phenomena of regenerating sensi-bility is simpler than that given by Dr. Head. In the mean-time the clinician must be content, we think, to reservejudgment. The exact import of the work here summarisedwill be seen better when it is put to the test of clinicalexperience. We consider, however, that Mr. Trotter
and Mr. Davies have by this minute and painstakinginvestigation made no small contribution to the solution of avexed problem, and have added lustre to the experimentalneurology of this country which Dr. Head’s researches havealready raised to so high a level.
THE PATHOGENESIS OF SYPHILITIC MUSCULARATROPHY.
AMONG the many minor though none the less fertile dis-cussions at the recent International Congress of Medicinewas one on the question of muscular atrophy in tabes andother syphilitic affections. Various opinions as to its patho-genesis have been held : the varying picture presented by thepathological anatomy of these cases is one reason for this
absence of unanimity. Tabetic amyotrophy in some caseais the result of ischæmia of the cord from syphilitic diseaseof the vessels or of the meninges. Sometimes it appears to
be the result of a peripheral neuritis ; sometimes thereis evidence to suggest a direct action of the syphiliticpoison on the nervous parenchyma-i.e., the anteriorhorn cells. Much light has been thrown upon the syphiliticorigin of tabes by the work of Dr. Hideyo Noguchi, whorecently gave a demonstration of his results at the RoyalSociety of Medicine.1 Dr. A. Barre, of Paris, in his con-tribution to the discussion said that in certain cases oftabetic amyotrophy important vascular lesions are present,consisting in subacute or chronic endo- and peri-arteritis andin endo- and peri-phlebitis. It would appear that theselesions have hitherto not had much attention directed to
them, but Dr. Barr6 held that some at least of the tabetic
amyotrophies are vascular in origin and isohæmic in character,and that from the pathogenic point of view these are closelyallied to the other trophic disorders of tabes more frequentlymet with-viz., arthropathies, perforating ulcers, &c. It iserroneous to regard these trophic changes as tabetic in thestrict sense ; the vascular modifications are essentiallysyphilitic, and whereas some have ascribed a preponderatingpathogenic r6le to lesions of the intramuscular nerves, Dr.Barre regarded both these and the actual muscular lesions assecondary to the vessel changes. A second hypothesis whichhe advanced is, in our opinion, more debatable. He thoughtthat the lesions of the anterior cornual cells not infrequentlyseen in tabetic atrophy might be secondary to the relativemuscular immobility and to the functional weakness whichresult from such muscular troubles. Dr. Barre regarded the
1 THE LANCET, Oct. 25th, 1913, p. 1187.
