On sclerosis of the spinal cord : including locomotor ataxy, spastic spinal paralysis, and other system-diseases of the spinal cord: their pathology, symptoms, diagnosis, and treatment

Front matter

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Hi'i^iiimM'M tt.'

ON

Preface

The subject of the present volume is one to which I have devoted much attention, and which I have had large opportunities of studying during the last fiveand-twenty years ; and I hope that my labours may go some way towards dispersing the obscurity which at present hangs over this department of medical science. I shall be especially gratified if my description of the protean forms which Tabes Spinalis or Locomotor Ataxy is found to assume in practice will in future lead to a readier recognition and a more successful treatment of that terrible malady. ISo one can be more fully aware than I am of the gaps which are still left in our knowledge of several of the spinal affections treated of in this volume ; and I have been particularly careful to indicate these in the course of my disquisitions, in the hope of giving an incentive to further work in a direction where it is most needed.

Sepff/inber, 1884. b

Contents

PAGE.

Introduction

Definition of Sclerosis or Induration — Different Forms of it — Systems of the Spinal Cord — Flechsig's Eesearches on Evolution — Burdach's or Postero-external Columns — Goll's or Postero-internal Columns— Direct Cerebellar Strands— Crossed Pyramidal Strands — Anomalies of Evolution the Base of the Neurotic Constitution .... l

Chapter II. Morbid Anatomy Of Tabes Spinalis

The Spinal Membranes— The Posterior Columns— Modes of Research—Hardening and Staining— Pierret' 8 and Striimpell's Researches on Posterior Sclerosis — Posterior Nerve-roots — The Spinal Ganglia— The Central Grey Matter— The Lateral Columns —The Sympathetic System of Nerves— The Brain— The Cranial Nerves— the Spinal Nerves— Researches by Pitres and Vaillard — Arthropathies . . •■..... 14

Chapter III. Pathogenesis Op Tabes

Theories of Duchenne and Neftel— The Brain— The Sympathetic System of Nerves— The Posterior Nerve-roots— Herbert Page's Corn-theory— Spinal Meningitis— The Blood Vessels, Neuroglia and Tubes of the Posterior Columns—" Sensitive Tabes " .38

Vlll CONTENTS,

PAGE.

Chapter IV. Morbid Anatomy Op Other Porms Op Sclerosis

Primary Sclerosis of the Lateral Columns — Spastic Spinal Paralysis — Erb's and Leyden's Views — Porencephaly — Secondary Sclerosis of the Pyramidal Strands — Sclerosis of the Direct Cerebellar Strands — Of GoU's Columns — Amyotrophic Lateral Sclerosis — Insular or Disseminated Sclerosis in Patches — Combined System-diseases — Friedreich's Disease — Pseudo- sclerosis . 51

CHAPTEE V.

ETIOLOGY.

Ergotism and Lathyrism — Barron's Eesearcbes on Lathyrism in Horses — Influence of Syphilis — Statistics of Syphilitic Tabes — Cases — Complication of Secondaries with Tabid Symptoms — Morbid Anatomy and Clinical Medicine — Period of Latency — Influence of Cold — Cases of Over-exertion — Cases of Accidents — Cases of Venereal Excesses— Of Drink — Of Tobacco-smoking— Of Acute Infectious Diseases — Of the Neurotic Constitution— Causes of Friedreich's Disease— Influence of Sex and Age — Causes of Spastic Spinal Paralysis— Of Insular Sclerosis — Of Amyotrophic Lateral Sclerosis ...... 68

Chapter VI. Symptoms Of Tabes Spinalis

Three Periods or Stages of the Disease . . . . .130

I. The First or Fre-ataxic Stage of Tabes.

1. Loss of Knee-jerk (Westphal's Symptom)— Its Physiology

and Diagnostic Importance — Cases — Does the Knee-jerk, when once lost, ever come back ?— Pseudo-knee-jerk . 132

2. Lightning-pains ; their Description and Physiology . . 146

3. Reflectory Rigidity of the Pupil (Argyll-Robertson's Symptom) 155

4. Mydriasis and Paralysis of the Ciliary Muscle .. . .160

5. Other Palsies of Ocular Muscles— Double Vision— Paralysis of

Sixth and Third Nerves— External and Internal Ophthalmoplegia 161

6. Olfactory Derangements : Anosmia, Hyperosmia and Parosmia 167

7. Amblyopia and Amaurosis — Optic Atrophy and Neuritis-

Colour-blindness 172

CONTENTS.

IX

PAGE.

8. Derangements of the Auditory Nerve : Inflammation of it —

Affection of the Nerve of Space — Vertigo.

9. Fifth-nerve Troubles : Hypersesthesia — Anaesthesia — Hemi-

atrophy of the Tongue .......

10. The Portio Dura and the Grlosso-pharyngeal Nerve— Paralysis

and Ataxy of the Facial Muscles .....

11. Crises and other Symptoms in the Sphere of the Pneumo-

gastric Nerve : — a. Laryngeal Crises— their Different Forms. h. Paralysis of the Abductors of the Vocal Cords

c. Spasm in the Gullet.

d. Gastric Crises .....

e. Cardiac Crises .....

12. The Spinal Accessory Nerve — Torticollis

13. Early Cerebral Troubles : — a. Aphasia and Paralysis h. Epileptic Seizures c. Failure of Brain Power .

14. Early Symptoms in the Sphere of Sensibility a. Hypersesthesia ....

h. Parsesthesia

e. Ansesthesia .....

15. Early Symptoms in the Motor Sphere .

16. Difficulties of the Bladder : — Sluggishness .

a.

b. Incontinence

c. Vesical Crises

17. Intestinal Troubles : —

a. Constipation .

b. Diarrhoea

c. Intestinal Crises

d. Incontinence .

18. Sexual Troubles : — a. Impotency h. Satyriasis

c. Nymphomania

d. Spermatorrhoea

e. Aspermatism .

19. Perforating Ulcer of the Foot

20. Arthropathies and other Trophic Affections — Joint-lesions —

Skin Diseases— Affections of Nails and Teeth— Muscular Atrophy

186 189 191 191 194 194

207 208

209 210 210 210

211 212 213 213 213 213

X CONTENTS.

PAGE,

21. Vasomotor Symptoms — Hyperidrosis — Anidrosis — Sialorrhoea

— Gastrorrhoea — Diarrhoea ...... 220

II. The Second or Ataxic Stage of Tabes.

22. Ataxy — The Initial Period — Tests for Ascertaining it —

Eomberg's Symptom— The Ataxic Gait — The Stage of Muscular Madness — Acute Ataxy — Ataxy in the Upper Extremities — Of the Ocular Muscles — Hemi-ataxy — Theories of Ataxy — Influence of the Central Ganglia and the Cerebellum 223

23. Sensibility : Lightning-pains — Numbness — Amesthesia — An-

algesias-Anaesthesia Dolorosa — Loss of the Sense of Temperature — Sense of Locality — Of Pressure — Tickling — Muscular Sensibility ....... 250

24. Eeflexes 262

25. The Urine 263

III. The Third or Terminal Stage of Tabes.

26. Late Brain-troubles — General Paralysis of the Insane —

Other Forms of Mental Disease— Modes of Death . . 263

Chapter VII. The Diagnosis Of Tabes Spinalis

The Pre-ataxic Stage : — Neursesthenia — Irritable Spine — Rheumatism and Gout — Diabetes — Optic Neuritis — Gastralgia — Enteralgia — Ulcer of Stomach — Cancer — Local Diseases of the Bladder and Urethra — Hemiplegia from Brain-disease 275

The Ataxic Stage : — Chorea — Paralysis Agitans — Multiple

Sclerosis — Disease of the Cerebellum — Spinal Meningitis . 287

The Terminal Stage ' .... 288

Chapter VIII. The Prognosis Of Tabes Spinalis

Opinions of Various Authors — Prognosis now more Favourable than formerly — Limited by Peculiarities of Structure of Affected Parts — Nerve Tubes more prone to Regeneration than Cells — General Remarks 290 contp:xts. xi

PAGE.

CHAPTEE IX.

THE TREATMENT OF TABES SPINALIS.

Eest — Habits — Diet — Anti-syphilitic Treatment - Inunction and Injection — Ergot of Eye— Nitrate of Silver — Injection of Silver — Chloride of Gold and Potassium— Electricity — Faradisation of the Skin — The Constant Cuirent — Central and Local Applications — Galvanic and Faradic Baths — Hydropathy — The Spas of Oeynhausen and Nauheim — The Aix-la-Chapelle Treatment — The Waters of La Malou — Nerve -stretching — Counter- irritation — Strychnia — Remedies for the Relief of Pain and of other Symptoms ........ 299

CHAPTER X. Friedreich's disease

Symptoms — Nystagmus — Absence of Sensorial Troubles — Course of the Malady — Prognosis and Treatment . . . .324

Chapter XI. Spastic Spinal Paralysis

Its Pathology and Causes — Loss of Power — Use of Special Dynamometer for the Lower Extremities — Its Value for Diagnostic Purposes — Symptoms of Motor Irritation — Influence of the "Warm Bath — The Spastic Gait — Progress of the Disease — Exaggeration of Tendon Reflexes — Ankle Clonus and Ejiee-jerk — Direct Percussion of Muscular Substance — Differences in Type : the Cerebral, Spinal, and Muscular Types — Anatomical Cause of the Exaggeration of Reflexes — Increased Reflexes without Paralysis — Affection of Sensibility — Cases — Diagnosis from Tabes, Transverse Myelitis, Cerebral Hemiplegia, Hysteria, Pseudo- Sclerosis, Amyotrophic Lateral Sclerosis and Insular Sclerosis — Prognosis— Treatment .... 328

Chapter XII. Amyotrophic Lateral Sclerosis

Affection of Upper Extremities — Of Lower Extremities — Signs of Labio-glosso-laryngeal Paralysis — Diagnosis — Prognosis — Treatmnnt .... , ..... 347

Xll CONTENTS.

PAGE.

Chapter XIII. Secondary Lateral Sclerosis

Descending Sclerosis of Pyramidal Strands after Cerebral Lesions — Destruction of tlie Internal Capsule Indispensable for its Production — Symptoms — Prognosis — Treatment — Spastic Paralysis in Children — Porencephaly — Injury from Obstetrical Operations — Epileptic Fits — Other Symptoms — Prognosis and Treatment^- Secondary Sclerosis after Haemorrhage into, and Crushing Lesions of, the Spinal Cord — Case .... 350

Chapter XV. Multiple Or Insular Sclerosis

Symptoms of the First Stage — Apoplectiform Seizures — Loss of Power — Symptoms in Children — In the Sphere of Sensibility — Tremor — Its Symptoms and Pathology — Case — Its Difference from Paralysis Agitans, Chorea and Tabes — Vertigo — Drawling Speech — Eye-Symptoms — Anosmiaand Deafness — State of Deep Reflexes — The Bladder, Rectum, and Sexual Organs — Amenorrhoea — Symptoms of Second and Third Stages — Diagnosis : from Friedreich's Disease, Spastic Paralysis, and Pseudo- sclerosis — Prognosis and Treatment 363

Chapter XVI. Pseudo- Sclerosis

Symptoms of Sclerosis without Anatomical Lesions — Cases . 381

Chapter XVII. Combined Postero- Lateral Sclerosis

Different Anatomical Localisations and Symptoms — Diagnosis . 383

Index op Authors 387

Index op Subjects 391

ON

SCLEEOSIS OF THE SPINAL COED.

Chapter I. Introdijction

There is no pathological term which is now-a-days so freely and somewhat loosely used in speaking and writing about the diseases of the nervous system as the word sclerosis. We hear and read not only of primary and secondary sclerosis, but also of posterior and lateral sclerosis, of descending and ascending, and of insular, disseminated and amyotrophic sclerosis. From having been at first simply used for designating certain morbid appearances found post-mortem in various portions of the nervous system, the term has gradually come to be employed for the nomenclature of diseases, tabes dorsalis or locomotor ataxy being now frequently called posterior sclerosis, and spastic paralysis being termed lateral sclerosis. In practice, any obscure and chronic case of nervous disease is now often spoken of as "a case of sclerosis," which is supposed to explain everything, and it cannot be denied that there is a good deal of confusion in the professional mind about what sclerosis really means and comprehends ; while the subject is so important that clear notions concerning it are highly desirable. Much that is new has recently been added to this department of pathology, and has, as usual, led to considerable improvement in diagnosis and treatment.

B

Although the term sclerosis (from o-fcXi?jooc, hard), or induration, is therefore now applied to a great variety of diseases of the spinal cord, it should be understood that we do not invariably find a very pronounced hardening of the structures which are affected in such cases. In some few instances, indeed, and notably so where the disease is comparatively fresh, the parts may actually appear to be softened ; but where the morbid process has been going on for a considerable time, as is, indeed, most frequeutly the case, the diseased tissues are decidedly tougher and harder than the normal ones, and may therefore be properly called sclerosed.

By sclerosis of the spinal cord I understand, then, an irritant morbid process, standing intermediate between inflammation and simple atrophy^ which invades certain well-defined and evolutionally, anatomically, and physiologically distinct areas or systems of that organ ; and which leads in course of time to disintegration and wasting of the nerve-tubes, very generally to partial or comjjlete destruction of the axis-cylinder, and to overgrowth of connective tissue. The best known of these affections is one with which we have long been familiar as tabes dorsalis, more recent synonyms being ^^rogressive locomotor ataxy (Duchenne), progressive locomotor asynergy (Trousseau), scZerosxs of the posterior columns (Erb), din^ posterior leuco-myelitis (Vulpian). The name locomotor ataxy does not appear to have been happily chosen, as the ataxy of gait, which constitutes the most prominent symptom of the fully-developed malady, is in many cases absent for years after the outbreak of the disease; the same applies to Trousseau's " asynergy "; while the other terms just mentioned only refer to the pathological anatomy of the complaint. The old term "tabes" therefore appears to be the best, and is now again gradually replacing the more recent appellations which had for some time past reigned supreme in the text-books and medical journals.

An apparently analogous affection of the lateral columns

INTRODUCTION.

of the cord has only recently been introduced into our system of nosology by Erb, who has called it spastic spinal paralysis ; while Charcot, who had investigated this subject about the same time independently, termed the disease

O-ff ceo

Transverse section of the spinal cord of the adidt : af, anterior fissure ; pf, posterior fissure ; c, spinal canal ; ac, anterior columns ; Ic, lateral columns ; pc, posterior columns ; ah, anterior horns ; ph, posterior horns; gs, gelatinous substance ; cc, Clark's columns; gc, Goll's columns ; be, Burdach's columns ; k, anterior commissure ; gg, ganglion cells of the anterior horns ; pio, bloodvessels of the pia mater ; «r, anterior roots ; pr, posterior roots.

spasmodic tabes dorsalis. Synonymous terms are primary lateral sclerosis (Berger),and sclerosis of the pyramidal strands (Dreschfeld). Ley den, however, denies the existence of this affection as a separate disease ; and as only slight

b2 evidence for it has as yet been furnished by morbid anatomy, the term " spastic paralysis " appears preferable, as it does not commit us to any definite theory about the nature of the malady.

No doubt exists about the occurrence of a combined affection of the white lateral columns and the grey anterior cornua, which was first distinguished by Charcot, and termed by him amyotrophic lateral sclerosis, the chief symptoms being motor paresis and rigidity, followed by atrophy of the muscular fibre. Another primary affection of this kind is multiple^ insular, or disseminated sclerosis, which is also called sclerosis in patches, and which may affect not only the different portions of the cord, more especially its antero-lateral columns, but also the medulla oblongata, pons varolii, the central white substance of the cerebellum, and the medullary substance of the cerebral hemispheres. In this disease the morbid process is, as a rule, not so severe as in tabes ; for while in the latter the nerve-fibre eventually perishes altogether, that important portion of it which is known as the axis-cylinder appears often to be spared in insular sclerosis. There are further anatomical differences between this and other forms of sclerosis, which will be fully described hereafter.

All forms of primary sclerosis are symmetrical, and only exceptionally confined to one half of the organ.

Secondary sclerosis, on the other hand, is mostly unilateral, and is the result of some other primary disease, such as haemorrhage into the brain, softening of the cerebral substance from embolism or thrombosis of blood-vessels, or of hfBmorrhage into the substance of the cord, and acute myelitis, Pott's disease of the vertebrae with compression of the cord, etc. When it occurs after destructive lesions of the motor area of the brain, it affects only that portion of the cord which corresponds physiologically to the diseased hemisphere, that is, the crossed pyramidal column,

INTRODUCTION. 5

and Tiirck's anterior or the direct pyramidal column. In these latter strands the disease occurs in a descending direction, while where secondary sclerosis affects the postero'internal or Goll's columns, it takes place in an ascending direction.

Clinical observation as well as morbid anatomy seem to point to the conclusion that all these different diseases are very closely allied to each other in character and appearances, and differ more particularly according to localisation.

It is a fact, which stands out more clearly as our knowledge advances, that fibres which have certain functions in common are liable to become diseased together at exceedingly different levels of the cord, while others in their immediate neighbourhood, which have different functions, are spared. Moreover, such fibres are liable to be affected symmetrically in the two lateral halves of the organ, the degree of the morbid change being often exactly parallel in both sides of the cord. The differences in the physiological function are naturally correlated to evolutional, anatomical, and possibly also to chemical differences in the several parts. Indeed, the cord consists, like the hrain, of a number of different areas or systems, each of which, although it may be histologically identical with others, yet follows a special type of evolution in the foetus, has different connections with more peripheral and more central parts, may possibly be chemically quite distinct from its surroundings, and lastly possesses peculiar pathological predispositions or proclivities which are not shared by contiguous parts, however closely connected with them in anatomical position, and however similar in histological elements.

An apt illustration of these peculiarities is afforded by the manner in which different poisons act on the different portions of the cord. Bread contaminated with ergot of rye will, when habitually taken for some time, cause well-marked disease of the posterior columns ; while bread containing an admixture of the laihyrus cicera, which is eaten bj the lower classes in certain parts of India, Algeria and Italy, will lead to equally striking symptoms of disease of the lateral columns. Strychnia has a special influence in exalting the excitability of the grey centre of the cord, and bromide of potassium diminishes it. Finally, lead will, when absorbed for some time consecutively, cause gradual disintegration of the large ganglionic cells of the grey anterior cornua, and thus lead to a peculiar form of muscular atrophy.

In order, therefore, to render the more minute pathology of the diseases under consideration thoroughly intelligible, it will be necessary for me to enter first into some explanation of the manner in which the highly complex structure of the spinal cord is built up and arranged. Histology and experimental physiology have done very little for the elucidation of this subject, while the study of evolution on the one hand, and of the finer pathological anatomy of the degenerations to which the organ is liable on the other hand, have been of the greatest service for unravelling the intimate structure and arrangement of the organ. Either of these methods of inquiry may be used for controlling the results given by the other, thus affording a greater degree of reliability than each one singly could do.

With regard to evolution, Flechsig^ has shown that the central nerve-fibre is at first laid down as a naked axis-cylinder, and that this latter is only much later furnished with a sheath of myeline. The latter is therefore a secondary formation, and is, in the several portions of the cord, developed at totally different periods of foetal life, just as well as the axis-cylinder itself. This mode of evolution follows a definite law with regard to time ; and it may thus be understood why tracts of fibres which are, anatomically speaking, at a considerable distance from each other, are,

INTRODUCTION.

in fact, far more closely related tlian others which may be much nearer neighbours.

The succession in which the evolution of the diSerent portions of the cord takes place, is as follows : —

1st. The fundamental strands of the anterior columns ;

2nd. The postero-external or Burdach's columns ;

3rd. The anterior mixed zone of the lateral columns ;

4th. The lateral terminal layer of grey matter ;

5th. The postero-internal or Goll's columns ;

6th. The direct cerebellar columns ; and, finally,

7th. The crossed pyramidal strands.

p

Section of the spinal cord from the region of the 5th cervical nerve from a foetus 12 centimetres long (after Flechsig). P, Tiirck's anterior pyramidal column ; A C, fundamental tracts of the anterior columns ; ALC, anterior mixed lateral column; pc^ processus reticulares ; CP, crossed pyramidal columns ; By Burdach's columns ; G, GoU's columns.

Of these seven different strands of the cord, those numbered 1, 2, and 3, viz., the fundamental strands of the anterior columns, Burdach's columns, and the anterior zone of the lateral columns, become developed at the earhest period of foetal life. The naked axis-cylinders are laid down at the end of the fourth week, and their myeline sheaths appear to be fully formed about the end of the fifth month, so that about four months are required for their completion. These three strands have another feature in common, viz., that their transverse section differs at different levels of the cord, being greatest in the cervical enlargement. The size of the transverse section is proportionate to the number of nerve-fibres which enter the strands. From this it is concluded that a large portion of the longitudinal fibres contained within these strands do not remain in the white matter of the cord, but leave it, after a longer or shorter course within the same, in order to proceed into the grey matter of the organ, where they terminate. They therefore connect, on the one hand, the grey matter of the cord with peripheral terminal organs, and on the other hand, different levels of the cord with each other.

BurdacVs or the postero-external columns (B, Fig. 2) are of chief interest for us here, as they appear to be principally selected by the morbid process in tabes. These columns are the bandelettes externes, or rubans externes, or zones radiculaires posterieures (posterior root-zones) of the French anatomists. The term "Burdach's columns," however, is the most convenient and the most generally accepted.

The transverse section of these, columns shows great variations. In the cervical enlargement they are more than twice the size of what they are in the middle dorsal portion, and in the lumbar enlargement only two-thirds of it. Their upper portion terminates in the nuclei of the funicuH cuneati of the medulla oblongata. They are the direct continuations of the posterior root-fibres, and therefore establish a direct and immediate connection of the cord with peripheral parts, and thereby with external influences. They are short conducting paths, inasmuch as the posterior root-fibres, which enter into them throughout their course, traverse them in a horizontal direction, or bend upwards or downwards to assume a longitudinal direction. When, therefore, at a given level of the cord numerous root-fibres enter, the calibre of the columns must be greater than where

INTRODUCTION.

the root fibres are few. On the median side of the posterior horns numerous fibres proceed from Burdach's columns into the grey matter of the cord, in a direction partly towards the posterior commissure, partly towards the posterior cornua, and partly towards Clarke's columns.

These parts contain fibres which connect different levels of the grey matter with each other, and others which proceed into the medulla oblongata. Most of them appear to terminate in the ganglionic cells of the formatio reticularis of the bulb, while another part communicates with the nuclei of the caudate columns and the corpora olivaria.

The French school of anatomists, as represented chiefly by Charcot, Vulpian, and Pierrot, have long taught that in tabes the morbid process begins in Burdach's columns, and that the internal portions of the posterior columns are only affected much later on, when the disease spreads to other parts. This proposition has for some time past been generally accepted; but more recent researches by German anatomists, more especially by Striimpell, of Leipzig, have shown that such is not by any means invariably the case; but that, at least in a certain number of instances, the most internal portion of G-oll's columns becomes sclerosed in the very commencement of the disease.

No definite law has as yet been formulated with regard to No. 4, the lateral terminal layer of the grey matter.

The postero-internal, or posterior median, or GolVs columns {G, Figs. 1 and 2), are laid down at the end of the second month, and the formation of their myeline sheaths appears to be finished at the end of the sixth month, giving again a period of four months for the entire process. These strands may only be clearly traced separately in the cervical and upper dorsal portions of the cord, and cannot be easily followed lower down. Their transverse section increases in diameter in a direction from below upwards, and they do not give fibres to the grey matter of the cord, but receive them from it; indeed their origin is in the grey matter of the cord. These fibres proceed from the internal aspect of the posterior cornua, and more especially from Clarke's columns and their immediate neighbourhood, and the posterior commissure. Although GoU's columns are only well seen separate in the cervical cord, there can be little doubt that they course all the way from the medulla oblongata to the lumbar enlargement, where their size is smallest. They terminate upwards in the nuclei of the funiculi graciles, and have to be looked upon as a special system of fibres on account of the quality and calibre of the nerve-tubes composing them, of their origin in the grey matter, and their relation to certain nuclei in the medulla oblongata. While Burdach's columns are short conducting paths, Groll's columns must be considered long conducting paths, intended to connect certain extra-medullary centres in the brain and cerebellum with physiologically identical fibre-systems at different levels of the cord.

The next system of fibres is called the direct cerebellar strands {Ce, Figs. 1 and 2). They are laid down at the commencement of the third month, while fully formed myeline-sheaths are first observed at the beginning of the seventh month, making again a period of four months taken up for their completion. They contain fibres establishing a connexion between the grey matter of the cord — probably more particularly Clarke's vesicular columns — and cerebellar centres. The fibres of these strands are shown to constitute a special system by the following points: — They spread equally in the grey matter of the cord, behave equally within the lateral columns, and have an equal course in the medulla oblongata. At the time of birth these strands may be seen sharply defined in the cervical cord, and are quite apart from the other portions of the lateral columns. They show a continuous increase in their transverse section, in a direction from below upwards, and may be traced as compact strands to the upper portion of the lumbar enlargement only.

INTRODUCTION. 11

Tlie last system of fibres which we have to consider (7) is that known as the crossed pyramidal strands. (CP, Figs. 1 and 2.) These are the latest of all formations.

Section of the spinal cord from the middle portion of the cervical enlargement of a foetus, 35 centimetres long (after Flechsig) . P, anterior pyramidal strand ; AE, anterior roots ; Ce, direct cerebellar columns ; CF, crossed pyramidal strands ; £, Burdach's columns ; G, GoU's columns. Magnified 6*4 lin.

They are first laid down about the middle of the fifth month, and the formation of their myeline-sheaths is only finished about the end of the ninth month, so that again a period of four months is seen to elapse between their beginning and their eventual completion. These strands contain exclusively fibres which are in connection with the cerebral hemispheres, through the pyramids of the medulla oblongata and the higher motor tracts; and they communicate with certain accumulations of grey matter in the brain, more especially the lenticular nucleus and the central convolutions of the cortex.

In other words, they contain all the fibres which form a direct connection between the grey matter of the cord, the central ganglia, and the motor portion of the cortex of the brain. They therefore constitute likewise a special system of fibres, having its own definite peculiarities and terminations. They have this feature in common with the direct cerebellar strands, that there is a steady increase in the diameter of their transverse section in a direction from below upwards. They are situated in the posterior half of the lateral columns, and may be traced down as far as the lower end of the lumbar enlargement, or to the third or fourth sacral nerve. They diminish in transverse section from above downwards, owing to their fibres successively entering the grey centre of the cord in that portion of it which connects the anterior and posterior cornua. They show immense individual variations in extent, inasmuch as the fibres which proceed from the motor region of the brain into the cord have the choice to course either in the same anterior, or the opposite lateral, column, before they proceed into the central grey matter.

From the foregoing description it appears that the different conducting paths in the spinal cord are laid down and developed in an absolutely systematic manner, and that at the same period of intra-uterine existence only one or several allied systems are formed. Those which are most important for the life of the foetus and which are reflectory by nature, are early developed, their faculty of incessant function being an indispensable condition for viability altogether. On the other hand, those tracts which place the spinal cord under the influence of the psychomotor centres, or the will, become evolved at a later period. These latter are more abundantly developed in man than in the lower animals, and are not formed at all in congenital absence of the brain, or in destructive disease of the motor area of the same.

As far as size is concerned, the anterior columns have been found to contain on the average 18 per cent., the lateral columns 46*6, and the posterior columns 35*4 per cent, of the white matter of the cord.

Anomalies of anatomical growth have probably a considerable influence on the evolution of diseases which occur later in Hfe. They may possibly be found eventually

INTRODUCTION.

IS to be the chief material base of what is now called the neurotic constitution. Congenital fissures or cavities may be the starting-point of certain diseases, causing tendency to the formation of glioma, glio-sarcoma, or chronic interstitial or parenchymatous degeneration. Singular irregularities in the distribution of the white and grey matter are not rarely met with in persons who have died of diseases of the nervous system. Schultze has found such anomalies in cases of spastic paralysis and general paralysis of the insane. Kahler and Pick discovered, in a person who had died of tabes, abnormal smallness and irregular shape of the central grey matter, and extreme smallness of the posterior columns, which was not exclusively owing to degeneration. As there are born statesmen, artists, and criminals, so there are no doubt some born to be sclerosed, and these are in general the descendants of the syphilitic, the gouty, and the alcoholised. The gradual formation of the myeline sheaths of the central nerve-fibre, which has been shown to follow a definite law throughout embryonic life, may in some cases be carried out in a deficient manner, and this may later on lead to disease of the imperfectly formed or not fully protected parts. Where undue claims are made upon a small or badly formed medulla oblongata or spinal cord, where connective tissue predominates over nerve-cells or fibres, there must be greater tendency to the development of asthma, diabetes, tabes, or paralysis, than there will be in cases where the essential constituents of these organs have been more abundantly and perfectly developed^