UC SOUTHERN REGIONAL LIBRARY FACILITY ate':- G 000 005 517 |j||| \ Sections of Spinal Cord of a Nine-months' Human Embryo, from the ) i Middle of the Lumbar and Cervical Enlargements, respectively * ■) Sections of the Adult Spinal Cord from the Middle of the Lumbar and \ J Cervical Enlargements, respectively ...... i ■) Sections of the Adult Human Spinal Cord, from the Upper Cervical \ i and Dorsal Regions, respectively .......' Section of the Medulla Oblongata on a level with the Superficial Origin of the Acoustic Nerve .......... 22 23 25 27 28 29 30 32 33 35 37 38 39 39 40 40 41 41 42 42 43 43 44 46 viii LIST OF ILLUSTRATIONS. FIG. PAGE 29. Transverse Section of the Cervical Part of the Spinal Cord of a Human Embryo of Six Weeks 47 30. Transparent Section of a Furrow of the Third Cerebral Convolution of Man 50 31. Pyramidal Giant-cell 51 32. Schema of the Cerebro-spinal System 52 33. Schema of the Cerebello-spinal System 55 34. Cord of Human Embryo at Five Months 56 35. Diagrammatic Kepresentation of Embryological Tracts .... 57 36. Diagram of the Gray Masses of the Spinal Cord and Brain, showing the course of the Conducting Paths 59 37. Diagram of Transverse Section of the Spinal Cord in upper half of the Dorsal Kegion ........... 00 38. Diagram of the Spinal Segment as a Centre and Conducting Medium . 61 39. Diagram of the Course of the Principal Conducting Paths within the Cord 66 40. Upper Surfoce of the Brain of the Monkey 71 ^2 I Side and upper Views of the Brain of Man I 73 43. Schema of Encephalo-spinal Action 76 44. Diagram Illustrating the Attachments of some of the most important Muscles which keep the Body in the Erect Posture .... 78 45. Horizontal Section of the Basal Ganglia and Internal Capsule of a Nine-months' Embryo .......... 86 46. Transverse Section of the Crus Cerebri on a level with the Anterior Pair of Corpora Quadrigemina, from a Nine-months' Embryo ... 87 47. Transverse Section of the Pons on a level with the Abducens and Facial Boots, from a Nine-months' Embryo ....... 88 48. Ganglion Cells of the Anterior Gray Horns of the Spinal Cord . . 97 49. Alterations in Nerve Fibres after Section ....... 98 f Transverse Section of the Spinal Cord, from the Middle of the Cervi- ] 50- I cal Enlargement, Dorsal Region and Lumbar Region, respectively, I rn ^ showing Ascending Degeneration of the Columns of Goll, and of I the Direct Cerebellar Tract ....... 53. Horizontal Section of the Right Hemisphere Parallel with the Fissure of Sylvius . . . . . . . . . . . .11.5 54. Horizontal Section of the Crura Cerebri in a case of Secondary De- generation . . . . . . . . . . . .116 Transverse Section of the Spinal Cord from the Middle of the Cer- ] vical Enlargement, Dorsal and Lumbar Regions, respectively, I showing Descending Sclerosis of the Pyramidal Tract in the !' I Lateral Column Secondary to a Cerebral Lesion ... 114 58. r Transverse Sections of the Spinal Cord, from the Middle of the T J Cervical Enlargement, Dorsal and Lumbar Regions, respectively, I ! showino- Primnrv T.ntprnl ."-ii^lorricic r\f tVio O.^i'A /-v^ ^inr^r^-r^A.^-.,,-, *„ C gQ* j showing Primary Lateral Sclerosis of the Cofd, or Secondary to f a Lesion high up in the Cord or Medulla Oblongata 61. Recent Softening of the Frontal Lobe, Island of Reil, and Middle Third of the Lenticular Nucleus . .117 119 140 142 1 1 164 165 _, LIST OF ILLUSTK ATIONS, 62. Diagram of Lesions found in the Anterior Half of the Lenticular Nucleus, Anterior Segment of the Internal Capsule, and the Internal Third of the Crusta . . . . . . . . . . _ .118 63. Diagram of the Optic Thalami, Tegmentum, and Superior Peduncles of the Cerebellum •-........ 64. Atrophy of Muscular Fibres from a case of Infantile Paralysis 65. Appearance of Muscle in Infantile Paralysis ..... 66- f Diagrams representing the General Kelations of Motor Power, go" -{ Electrical Excitability and Structural Changes of the Nerves and gg I Muscles present in Different Stages of Paralysis 70. Diagram and Table showing the Approximate Eelation to the Spinal Nerves of the Various Sensory and Keflex Functions of the Spinal Cord 174 71. Diagram of the Keflex Functions of the Spinal Cord .... 180 72. Schema explaining Conjugate Deviation of the Eyes and Kotation of the Head and Neck 186 73. Superior Cervical Ganglion of the Sympathetic: its Connections and Branches ............ 195 74. Nervous Mechanism of the Iris . ........ 197 75. Schema of the Action of the Cardiac Nervous Mechanism . . . 205 76. Diagram showing the Probable Plan of the Centre for Micturition . . 213 77. Sensory Nerves of the Head and Face ....... 246 78. Diagram of the First and Second (Superior Maxillary) Divisions of the Fifth Nerve : its Connections and Chief Branches .... 248 79. Diagram of the Third (Inferior Maxillary) Division of the Fifth Nerve its Connections and Chief Branches ...... 80 "> > Cutaneous Nerves of the Trunk ; Upper Extremity 250 251 259 261 271 275 81./ 82. Cutaneous Nerves of the Lower Extremity ..... 83. Distribution of Keddened Surface in Neuralgia Plantaris . 84. Diagram of Glosso-pbaryngeal Nerve: its Connections and Branches 85. Diagram showing the Fields of Color Vision in a Normal Emmetropic Eye on a Dull Day 86. Horizontal Section through the Optic Nerve at its Point of Insertion in the Globe, and its Passage through the Membranes of the Eye 87. Diagram of Decussation of the Optic Tracts .... 88. Section of the Medulla Oblongata on a level with the Largest Diameter of the Diseased Focus, which is represented by the Shaded Part on the Left Half of the Diagram ...... 89. Spasm of the Trapezius ....... 90. Spasm of Splenius ........ 91. Contraction of the Khomboid Muscles .... 92. Position of the Hand in Spasm of the Interosseous Muscles 93. Diagram showing Position of Body in Tetanus 94. Diagram showing Lesion in Crural Monospasms 95. Diagram showing Lesion in Brachial Monospasm 96. Diagram showing position of Eyeballs in a case of Oculo-motor Mono- spasm ............. 326 280 284 285 308 305 306 308 316 324 325 X LIST OF ILLUSTRATIONS, FIG. 97. External Convex Surface of the Human Brain 98. Diagram of the First or Ophthalmic Division of the Fifth, showing also the Third, Fourth, and Sixth Cranial Nerves 99.1 . [: 360 867 372 374 100. [- Disorders of Movements of Eyelids 101. J 102. Kelations of the False to the True Image 108. Diagram of the Facial Nerve: its Connections and Branches 104. Diagram of the Hj'poglossal Nerve : its Connections and Branches 105. Diagram of the Pneumogastric and Spinal Accessory Nerves : their Con nections and Branches ......... 106. Distortion of the Uvula in a case of Peripheral Paralysis of the Eight Side of the Face 107. Schema of a Horizontal Section through the Larynx 108. Schema of a Horizontal Section through the Larynx, showing the Action of the Arytenoid Muscles ...... 109. Schema of Horizontal Section through the Larynx, illustrating the Action of Crico-arytenoidei Laterales Muscles .... 110. Laryngoscopic Appearances of the Interior of the Larynx 111. Laryngoscopic Appearance of the Larynx during Quiet Breathing 112. The Laryngoscopic Appearance of the Larynx during Vocalization 113. The Laryngoscopic Appearance of the Larynx during Deep Inspiration showing the Bifurcation of the Trachea ..... 114. Nerves of the Cervical Plexus ........ 115. Nerves of the Brachial Plexus . ....... 116. Paralysis of the Serratus Magnus ....... 117. Distribution of the Sensory Nerves on the Back of the Hand 118. Showing the Distribution of the Anaesthesia in a case of Division of the Musculo-spiral Nerve in the Arm .'.... 119. The Dorsal Aspect of the Hand two weeks after Kesection of the Kadial Nerve ............ 121 [Cutaneous Nerves of the Trunk and Upper Extremity . 122. ■) Pvadial Border and Dorsal Aspect of one Hand, showing the Distri l-^^- i bution of Aniesihesia in a case of Division of the Median Nerve 124. Showing the Distribution of the Aniesthesia on the Back of the Fingers in a case of Injury of the Median Nerve 39-5 125. Main en GritFe 3 Lesions in Acute Spinal Atrophic Paralysis / ^'3'^ 141. Transverse Section of the Spinal Cord and Medulla Oblongata at dif- ferent levels, from a case of Chronic Atrophic Spinal Paralysis, show- ing the Disappearance of the Ganglion Cells 4.j7 142. Transverse Section of the Spinal Cord from the Middle of the Cervical Enlargement, from a case of Syringomyelia, showing a Cavity behind the Posterior Commissure, and Destruction of a large portion of the Ganglion Cells of the Anterior Gray Horns ...... 4.58 143. Transverse Section of the Cervical Enlargement of the Spinal Cord, showing a Central Cavity which has destroyed considerable portions of the Anterior Gray Horns ......... 4.j8 144. Transverse Section of the Cervical Region of the Spinal Cord, from a case of Progressive Muscular Atrophy ....... 4-59 145. Transverse Section from the Middle of the Cervical Enlargement of the Spinal Cord, from an advanced case of Progressive Muscular Atrophy 460 146. Transverse Section of the Spinal Cord from the Middle of the Cervical Enlargement, showing that the Central Column and a large portion of the Anterior Gray Horns are Diseased . . . . . .461 147. Portion of the Gray Substance on the Floor of the Fourth Ventricle on a level with the Middle of the Hypoglossal Nucleus, from a case of Progressive Muscular Atrophy with Bulbar Paralysis, showing the Destruction of the Ganglion Cells of the Nuclei of the Hypoglossal and Pneumogastric Nerves ......... 462 148. Muscular Fibres from a case of advanced Infantile Paralysis withdrawn hy Leech's Trocar ........... 464 149. Muscular Fibres in Various Stages of Degeneration, from a case of Pseudo-hypertrofhic Paralysis ........ 466 150. Attitude of the Hand and Forearm in Amyotrophic Lateral Sclerosis . 475 151 1 1 r:,o f Spasmodic Paraplegia of Infancj' ■ 484 153. Transverse Section of the Medulla Oblongata on a level with the Middle of the Nucleus of the Hypoglossal 490 154. Horizontal Section of the Basal Ganglia and Internal Capsule in an Embryo of Nine Months 491 155. Vertical Section of the Brain a little behind the Knee of the Internal Capsule, showing the Effects of Rupture of the Lenticulo-striate Artery 492 156. Vertical Section of the Brain on a level with the Posterior Part of the Internal Capsule, showing the Effects of Rupture on the Lenticulo- optic Artery (Hemianissthesia) ........ 494 157. Crura Cerebri. Transverse Section of the Crura Cerebri on a level with the Anterior Pair of the Corpora Quadrigemina, from a Nine-months' Human Embryo ........... 495 158. Diagram showing Decussation of Fibres of Pyramidal Tract at the Middle of the Pons 496 Xll LIST OF ILLUSTRATIONS. 159. 160. 161. 162. 163. 164. 165. 166. 167. 168. 169. 170. 171. 172. 173. 174. 175. 176. 177. 178. 179. 180. 181. 182. 183. 184. Dia:;rftni of Defect of Parietal Bone in a case of Congenital Paren- cephalus .......... Appearance of Brain in a case of Congenital Parencephalus i Diagram of Lesion in Crural Monoplegia Diagram of Lesion in Brachio-crural Monoplegia . Diagram of Lesion in Brachio-facial Monoplegia . Diagram of Lesion in Facial Monoplegia Diagram of Lesion in Unilateral Oculo-motor Monoplegis [-Diagram of Lesion in Hemiplegia from Cortical Disease Transverse Section of the Lumbar Region, from a case of Locomotor Ataxia, complicated with Muscular Atrophy Region of Anaesthesia in a case of Hemorrhage into the Upper Dorsal Region of the Right Side of the Cord Diagram of the Cutaneous Symptoms in Unilateral Lesion of the Dorsal Portion of the Spinal Cord on the Left Side ...... Section of the Middle of the Cervical Enlargement of the Spinal Cord from a case of Central Myelitis ........ Diagram of the Course of the Principal Conducting Paths within the Cord Distribution of Aniesthesia in Pacliymeningitis Cervicalis Hypertrophica Attitude of the Hand in Pachymeningitis Cervicalis Hypertrophica, when the Lesion is situated on a level with the Upper Half of the Cervical Enlargement .......... Diagram of Lesion in a ca.se of Aphasia ....... Diagram showing the Area of Distribution of the Middle Cerebral Artery ............. Diagram of Lesion in a case of Word-deafness ..... Attitude of the Hand in Paralysis Agitans ...... Attitude of the Hand in Paralysis Agitans simulating that of Arthritis Deformans ............ Section of Anterior Gray Horn of the Cervical Enlargement of the Spinal Cord, from a case of Chorea that died on the Fourth Day of Scarlet Fever ............ Section of the Cervical Region of the Spinal Cord, from a case of Chorea View of the Posterior Surface of the Medulla Transparent Lateral View of the Medulla 498 499 500 501 501 502 503 505 505 506 532 544 559 563 566 572 573 644 645 646 672 673 684 685 697 698 CONTENTS. CHAPTER I. ANATOMICAL INTRODUCTION. Formation of Nervous Constituknts Formation of Nervous Tissues . Formation of a Nervous System Encephalo-spino-neural System ■ PACK 18 19 19 21 CHAPTER II. PHYSIOLOGICAL INTRODUCTION. 1. Functions of the Spino-neural System 65 2. Functions of the Encephalo-spinal System 67 3. Functions of the Cerebro-spinal System 68 4. Functions of the Cerebello-spinal System 75 5. Cooperation of the Cerebro-spinal and Cerebello-spinal Systems 76 CHAPTER III. GENERAL MORBID ANATOMY AND PHYSIOLOGY OF THE NERVOUS SYSTEM. I. General Morbid Anatomy ......... 90 1. Defects of Development ......... 90 2. Dissolution of the Nervous System ....... 93 3. Dissolution of the Nervous System (continued) 108 II. General Morbid Anatomy and Physiology 122 CHAPTER IV. GENERAL SYMPTOMATOLOGY. A. The .^Esthesioneuroses ...... I. The Primary ^Esthesioneuroses .... II. The Secondary or Compound .^Esthesioneuroses 125 125 135 XIV CONTENTS. CHAPTEK V. GENERAL SYMPTOMATOLOGY {continued) B. Tkoi'iioneurosks I. Neurotic Atrophy of Muscle . II. Cutaneous Trophic Affections . III. Trophic Disorders of the Nails and Hair IV. Bedsores and other Destructive Processes V. Nutritive Affections of the Joints, Bones, and Teeth (Articular and Osseous Trophoneuroses) ...... VI. Nutritive and Secretory Affections of the Glandular Apparatus VII. Nutritive Affections of the Viscera (Visceral Trophoneuroses) PAOE 140 140 143 145 146 151 15.3 1.56 CHAPTER yi. GENERAL SY:MPT0MAT0L0GY' (continued). C. The Elementary Kinesioneuroses 158 T. The External Kinesioneuroses 158 CHAPTER VII. GENEPvAL SY'MPTOMATOLOGY {continued). C. The Elementary Kinesioneuroses {continued) . II. The Visceral Kinesioneuroses ...... III. Vascular Kinesioneuroses or Angioneuroses CHAPTER VIII. GENERAL TREATMENT 1. Prophylactic Treatment 2. Removal of the Exciting Cause . 3. Removal of the Anatomical Cause . (a) Internal Remedies .... {b) External Remedies .... 4. To Allay or Remove Serious Symptoms 194 194 21() 222 223 223 223 225 234 SPECIAL PATHOLOGY OF THE NERVOUS SYSTEM. CHAPTER I. GENERAL DISEASES OF THE PERIPHERAL NERVES. 1. Hyper.emia or Congestion of the Nerves 237 2. Inflammation of Nerves (Neuritis and Perineuritis) . . . 237 o. Atrophy of Nerves 239 4. Hypertrophy of Nerves 240 5. Nkuromata . „.„ 240 CONTEXTS. XV CHAPTER II. DISORDERS OF COMMON SENSATION AND OF SPECIAL SENSE. PAGE I. Anaesthesia and Analgesia in thk Region of Distribution of Individual Nerves and Plexuses 243 II. Hyper.esthesia and Hyperalgesia in the Region of Distribu- tion of Individual Nerves and Plexuses .... 244 III. Neuralgia in the Region of Distribution of Individual Nerves AND Plexuses . 24") 1. Neuralgia of the Fifth Nerve (Trigeminal Neuralgia) . . 24') 2. Cervico-occipital Neuralgia ......... 2-")2 3. Phrenic Neuralgia 252 4. Cervico-brachial Neuralgia ........ 253 5. Dorso-intercostal Neuralgia . . ..... 254 6. Lumbar Neuralgia 255 7. Neuralgia of the Sacral and Coccygeal Nerves ... 257 8. Visceral Neuralgia .......... 2()2 IV. Disorders of the Nerves of Si'f.cial Skxse 2G7 1. Diseases of the Olfactory Nerve 2G7 2. Diseases of the Acoustic Nerves ... .... 269 3. Diseases of the Gustatory Nerves 270 4. Diseases of the Optic Nerves 273 V. Disorders Caused by Disease of the Cerebro-Spinal Sensory Conducting Paths 284 VI. Disorders Caused by Disease of the Cortical Sensory Centres. 288 1. Cutaneous and Muscular Hemiantcsthesia 288 2. Disorders of the Sense of Smell .....•■■ 288 3. Disorders of the Auditory Sense 289 4. Disorders of the Visual Sense -Bft CHAPTER III. SPASMODIC DISORDERS I. Spino-neural Spasms 1. Local Spasms 2. General Spino-neural Spasms 3. Myopathic Spasms CHAPTER IV. SPASMODIC DISORDERS {coniinned). 295 295 313 321 323 II. Cerebro-spinal Spasms 1. Spasms from Organic Disease of the Cortex of the Brain (Monospa.sms and Unilateral Convulsions) '^23 2. Spasmodic Atfections from Functional Disease of the Cortex of the Brain .....•••■••• 327 CONTENTS. CHAPTER V. ATROPHIC PARALYSES. Simple Nkural Paralyses 1. Paralysis of the Oculo-motor Nerves 2. Masticatory Paralysis 3. Paralysis in the Area of Distribution of the Seventh Nerve (Mimetic Paralysis, Hemiplegia and Diplegia Facialis, Prosopalgia, Bell's Paralysis) ....••••••• 4. Paralysis of the Muscles Supplied by the Hypoglossal Nerve (Glosso plegia) 5. Paralysis of the Pneumogastric Nerve (j. Paralysis of the Spinal Accessory Nerve . 7. Paralysis of the Muscles Supplied by the Cervical Plexus 8. Paralysis of the Muscles Supplied by the Brachial Plexus 9. Paralysis of the Muscles Supplied by the Dorsal Nerves 10. Paralysis of the Muscles Supplied by the Lumbar Plexus 11. Paralysis of the Muscles Supplied by the Sacral Plexus PAGE 356 356 363 365 371 373 383 385 389 402 403 408 CHAPTER VI. ATROPHIC PARALYSES {continued). II. Multiple Neural Paralyses . 1. Idiopathic Progressive Multiple Neuritis 2. Lead Paralysis ..... 3. Alcoholic Paralysis .... 4. Diphtheritic Paralysis .... III. Reflex Atrophic Paralyses 412 412 413 415 418 422 CHAPTER VII. ATROPHIC PARALYSES {continued). lY. Spinal Atrophic Paraly'ses (Poliomyelopathies) . . . 425 1. Paralysis Ascendans Acuta (Acute Ascending Paralysis, Landry's Paralysis) ............ 425 2. Poliomyelitis Anterior Acuta (Kussmaul) (Acute Inflammation of the Anterior Gray Horns, Acute Atrophic Spinal Paralysis) . . 426 3. Poliomyelitis Anterior Chronica (Chronic Atrophic Spinal Paralysis) 434 4. Periependymal Myelitis (Syringomyelia, Hydromyelia) . . . 436 5. Progressive Muscular Atrophy 437 6. Primary Labio-glosso-laryngeal Paralysis (Chronic Progressive Bulbar Paralysis (Wachsmuth)) 442 7. Ophthalmoplegia Externa vel Progressiva 447 V. Myopathic Atrophic Paralysis 448 Pseudo-hypertrophic Paralysis and Erb's Juvenile Form of Progressive Muscular Atrophy 448 Morbid Anatomy and Physiology of the Atrophic Paralyses . . . 4-54 CONTENTS. xvii CHAPTER VIII. THE SPASMODIC PARALYSES. I'AOE I. Paraplkgi^e 471 1. Primary Lateral Sclerosis (Tabes Dorsalis Spasinodica (Charcot), Spas- modic Spinal Paralysis) . . . . . . . . .471 2. Amyotrophic Lateral Sclerosis ........ 474 3. Secondary Lateral Sclerosis ......... 470 II. Hemiplegia: 476 L Ordinary Hemiplegia .......... 470 2. Hemiplegia and Hemiansesthesiu ........ 477 3. Hemiplegia, Heinianuesthesia, and Hemianopsia ..... 477 4. Crossed Hemiplegia . . . .• . . . . 477 5. Hemiplegia and Post-hemiplegic Spasms ...... 478 III. Special Consideration of Post-hemiplegic Spasms as they occur IN Infancy (the Spasmodic Paralyses of Infancy) . . 482 1. Spastic Hemiplegiae of Infancy 482 2. The Spasmodic Paraplegiije of Infancy ...... 484 IV. Monoplegia 485 V. Paralyses from Functional Disease ...... 485 1. Post-epileptic Paralysis ......... 485 2. Hysterical Paralysis • . . 486 3. Toxic Paralyses 488 Morbid Anatomy 489 I. Paraplegia 489 II. Hemiplegia ........... 491 III. Special Consideration of Lesions of the Pyramidal Tracts as they occur in Infants .......... 497 IV. Monoplegia 499 CHAPTER IX. DISORDERS OP MOTOR COORDINATION. 1. Meniere's Disease (Aural or Labyrinthine Vertigo) . . . 509 2. Primary Sclerosis of the Columns of Goll 510 3. Secondary Sclerosis of the Columns of Goll and of the Direct Cerebellar Tracts 511 4. Progressive Locomotor Ataxia (Tabes Dorsalis, Gray Degenera- tion or Sclerosis of the Posterior Columns of the Spinal Cord) 511 (1) The Preataxic Stage 512 (2) The Ataxic Stage 521 (8) The Paralytic Stage 526 5. Combined Sclerosis of the Posterior ajsd Lateral Columns . 528 6. Diseases of the Cerebellum 528 PAGE CONTENTS, CHAPTER X. VASCULAR DISEASES OF THE SPINAL CORD. I. Anemia, Thrombosis, and Embolism of the Spinal Cord (Myelo- malacia, Vascular Spinal Sclerosis) 539 II. HYPERiEMIA and HEMORRHAGE OF THE SPINAL CORD . . . 540 L Spinal Uyperaemia 540 2. Spinal Apoplexy (Hajmatorayelia) 541 CHAPTER XI. MYELITIS. Varieties of Diffused Myelitis 551 1. Central Myelitis 551 2. Bulbar Myelitis • .552 3. Transverse Myelitis 552 4. Wounds of the Spinal Cord 554 5. Compression Myelitis (Tumors in the Vertebral Canal) . . . 556 6. Spinal Hemiplegia and Hemiparaplegia (Unilateral Lesion of the Spinal Cord) 557 7. Meningo-myelitis ........... 500 8. Universal Progressive Myelitis 560 9. Disseminated Myelitis .......... 561 CHAPTER XII. DISEASES OF THE SPINAL MEMBRANES. I. Vascular Diseases of the Spinal Membranes .... 569 1. Hj'peraemia .........'... 569 2. Hajmatorrhachis (Meningeal Apoplexy) ...... 569 II. Inflammation of the Spinal Dura Mater (Pachymeningitis Spinalis, Perimeningitis) 570 1. Pachymeningitis Spinalis Externa (Peripachymeningitis) . . . 570 2. Pachymeningitis Interna . . .571 III. Inflammation of the Spinal Pia Mater and Arachnoid (Lepto- meningitis Spinalis; Perimyelitis and Arachnitis) . . 574 1. Leptomeningitis Spinalis Acuta ........ 574 2. Leptomeningitis Spinalis Chronica ....... 575 CHAPTER XIII. CERTAIN FUNCTIONAL DISEASES OF THE NERVOUS SYSTEM. 1. Spinal Irritation 578 IL Neurasthenia 579 III. Headache (Cephalalgia) 584 Hemicrania 586 CONTENTS. XIX CHAPTER XIY. saocK, coxcussioisr, and allied conditions. I. Shock . II. Concussion of the Spinal Cord (Commotio Spinalis) Varieties of Spinal Concussion ..... III. Concussion of the Brain IV. Contusion of the Brain ...... V. Compression of the Brain PAGE 594 596 596 598 599 600 CHAPTER XY. VASCULAE DISEASES OF THE BRAIN. I. Anemia and Occlusion of the Intracranial Vessels . . 603 1. Universal Cerebral Anaemia ........ 603 2. Partial Cerebral Anemia (Occlusion of the Intracranial Ves«els . 604 II. C0NGE.ST10N of the Brain 608 III. Intracranial Hemorrhage 610 1. Cerebral Hemorrhage (Apoplexy) ....... 610 2. Meningeal Hemorrhage ......... 615 CHAPTER XYI. ENCEPHALITIS. Diffused or General Encephalitis 620 Partial or Local Encephalitis 620 1. Poliencephalitis Acuta Infantium ....... 621 2. Traumatic Local Encephalitis ........ 621 3. Acute Pyiemic Encephalitis ........ 622 4. Encephalitis Complicating Preexisting Lesions of the Brain . . 623 CHAPTER XVII. ATROPHY, HYPERTROPHY, AND TUMORS OF THE BRAIN. I. Atrophy of the Brain 630 1. Atrophy of the Corpus Callosum ....... 630 2. Atrophy of the Cerebellum ........ 630 3. Atrophy of the Cerebral Hemispheres ...... 630 II. Hypertrophy of the Brain 631 1. General Hypertrophy of the Brain ....... 631 2. Partial Hypertrophy or Heterotopia of the Brain Substance . . 631 III. Intracranial Tumors 632 CHAPTER XYIII. APHASIA. Motor Aphasia Sensory Aphasia (Amnesic Aphasia) Mixed Motor and Sensory Aphasia .... 638 640 643 CONTENTS. CHAPTER XIX. DISEASES OF THE MEMBRANES OF THE BRAIN. PAGE I. DrSKASES OF THE DuRA Mater 651 (I.) External Pachymeningitis 651 (II.) Internal Heniorrnagic Pachymeningitis (Hjematoma of the Dura Mater) 651 II. Diseases of the Pia Mater. 653 (I.) Tubercular Meniningitis (Acute HydrocephHliisj .... 653 Chronic Hydrocephalus ......... 658 (II.) Meningitis of the Convexity of the Brain 660 (III.) Simple Meningitis of the Base of the Brain (Basilar Meningitis) 663 (IV.) Metastatic Meningitis 664 (V.) Traumatic Meningitis 665 CHAPTER XX. PAPvALYSIS AGITANS, MULTIPLE SCLEROSIS, AND CHOREA. I. Paralysis Agitans 670 II. Multiple Sclerosis of the Brain and Spinal Cord (Dissemi- nated OR Insular Sclerosis) 674 III. Chorea 679 CHAPTER XXI. GENERAL DIAGNOSIS. 1. Clinical Diagnosis 690 2. Topographical Diagnosis 691 3. Pathological Diagnosis 699 Syphilis of the Brain ... . .... 705 DISEASES OF THE NERVOUS SYSTEM. /4387 CHAPTEK J. ANATOMICAL INTRODUCTION. Before entering upon the study of the nervous system it is desirable to lay down a foAV general principles, to which all nervous structures, with their corresponding functions, must conform. The key to the interpretation of the form assumed by the constituent parts of the ner- vous SA'Stem, and of the actions performed by each part, is best obtained by a close study of the order of development of nervous structures and functions as manifested in passing from the lower to the higher animals, and from the initial to the adult stages of animals. The knowledge obtained by these studies constitutes the comparative anatomy and em- bryology of the nervous system. The great law to Avhich all developing organisms and organs, as well as all developing functions, must conform is the law of evolution. This law may be defined as a progressive integration of structure and function, during which there is a passage from the uniform to the multiform, from the simple to the complex, and from the general to the special. In the lowest organisms, which consist of individual cells, or of an aggregation of cells without definite parts, each part performs all the vital functions. Each part possesses the fundamental property of irrita- bility, and is capable of initiating movement, or, in other words, is automatic and contractile, and each is likewise metabolic, excretory, and reproductive. But on ascending in the scale of organization it is found that certain parts of the organism acijuire the power of performing more perfectly a few functions, and ultimately one special function, while losing to a greater or less extent the power of performing the general functions. One part or tissue, for example, becomes adapted to the performance of the functions of contraction, while at the same time it gives up the functions of initiating movement and reproduction. 18 ANATOMICAL INTRODUCTION. and only performs the metabolic and excretory functions in a very subor- dinate degree. This process has been named a " physiological division of labor," or a "specialization of function," when regarded from the point of view of the actions of the organism, and its anatomical counter- part in development is to be found in what is known as the "differen- tiation of structure." FORMATION OF NERVOUS CONSTITUENTS. The first beo-inning of a differentiation of the nervous from the other elements of organisms is well illustrated in Hydra. In this organism the internal end of an ectodermic cell is prolonged into a process, which, being shielded from external influences, tends only to contract when it receives a stimulus through the external end. In other words, the internal end performs the work, and the external determines when the work shall be done : the one is operative, the other regulative. This differentiation of structure is carried still further in Beroe, where the internal and external ends of the ectodermic cells are represented by two different cells connected by a thin fibre. The changes set up in the external or sensitive cell are conducted through the fibre to the internal cell, which it excites to contract. This new arrangement of fibre introduces us to a new specialization of function. The regulative or automatic cell and the work cell are separated from each other by a considerable distance, but the molar contraction of the one is coordinate with the molecular motion of the other by the internuneial function of the fibre. The property the fibre possesses of transmitting the state of activity from one end to the other is called its conductivity. The next step in development consists in the differentiation of the external or sensitive cell into two : one of which becomes adapted to responding to external stimulation alone, and the other to modifying the impulses which are sent to it from the external cell and trans- mitting them to the work cell. The nervous mechanism now consists of an external sensory cell, an afferent fibre connecting it with a cen- tral regulating cell, and an efferent fibre or fibres connecting this last with work cells. This mechanism constitutes a rejiex loop, and its function is named rejiex action. One other complication of this simple mechanism may be mentioned : When an automatic or reflex cell is already engaged in action, a new stimulus brought to it by means of a second afferent fibre may check, instead of still further exciting that action, so that this function introduces us to inhibitory as well as excito- motor fibres. The inhibitory fibres are either afferent, or connect one central cell with another central cell, being then intercentral, and prob- ably never connect a central cell directly with a work cell. FORMATION OF A NERVOUS SYSTEM. 19 FOKMATION OF NEEVOUS TISSUES. On looking at a simple nervous system, the greatest contrast in structure is manifested between certain knots termed ganglia and certain cords termed nerves, and, since these parts exhibit the greatest structural contrast existing in the nervous system, they may also be expected to exhibit the widest functional contrast. The ganglia are composed of nerve cells, with their connecting processes, held together by a fine connective tissue ; and the nerves are composed of nerve fibres arranged side by side in a bundle — these being also held together by a firm connective tissue and by a fibrous sheath. Functionally regarded, the ganglia are originators of motion, and, to some extent, conductors also ; while the nerves are mainly conductors, although it is probable that they are also in some small degree origin- ators of motion. A still further examination shows that the afferent fibres are provided Avith peripheral end-organs, which are adapted for receiving impressions from environing agents and objects ; while the efferent fibres are provided with arrangements by means of which the molecular motion of the nervous system is transmitted into the molar motion of the work organs. FOKMATION OF A NERYOUS SYSTEM. It has just been seen how the cells and fibres which constitute the nerve elements integrate so as to form the simple tissues, and now we must follow this progressive integration to still higher stages. In the higher animals, the ganglia, instead of appearing as small knots, have come, by approximation and fusion, to form a continuous mass, which, from its color, is termed the gray substance; and the fibres, instead of always appearing as cords connecting separate ganglia, also form a con- tinuous mass called the white substance. Now, this fusion of nerve centres and nerve strands takes place when the functions are integrated in corresponding degree, and fails to take place when the functions remain in large measure independent of one another. The internal organs of the body which are derived from the hypo- blast of the embryo are much more independent of one another in their actions than are the external organs derived from the epiblast ; and the functions of the former are regulated chiefly by means of the ganglia of the sympathetic system, which are only connected by small cords, while those of the latter are regulated by means of large masses of gray and white substance, which constitute the encephalo-spino- neural system. 20 ANATOMICAL INTEODUCTION. ■ The parts of tlie body which are derived from the mesoblast form a system of organs which serve to connect the external and internal or<^ans ; and fn so far as the intermediate tissues subserve the functions of ''the external organs their actions are regulated from the encephalo- spinal and the spino-neural centres ; and when they subserve the func- tions of the internal organs their actions are regulated by the sympa- thetic system ; while in so far as their function is intermediate between the internal and external organs, but partially independent of them, their actions are regulated by an intermediate and partially inde- pendent system, termed the vaso-motor. A plane passing longitudinally and from behind forwards through a human being bisects the body into two bilaterally symmetrical divisions, and this statement is equally true of the nervous system as of the body as a whole. The sympathetic system of each half of the body is rep- resented by a gangliated cord, which is situated along the side of the vertebral column ; while the encephalic and spinal systems of each side are represented by the cerebral and cerebellar hemispheres, the crus cerebri, and the lateral halves of the pons, medulla oblongata, and spinal cord. Although the two lateral halves of the body are more or less symmetrical, the organs of the one side are to a considerable extent dependent upon those of the other in their functions, and consequently the actions of the organs of the two sides must be duly coordinated. The structural counterpart of this interdependence is to be found, in the case of the sympathetic system, in the plexus of fibres and small ganglia which pass in front of the vertebral column and connect the ganghated cords of the two sides with one another ; and in the en- cephalic and spinal systems by the commissures of the spinal cord, the median raphe of the medulla oblongata and pons, the middle peduncles of the cerebellum, the commissures of the third ventricle, and the coi'pus callosum. The body is composed of segments placed end on end, and there is a similar distribution of the nervous system. That this is the case with the greater part of the sympathetic is readily recognized. Each segment of the body is represented by a vertebra and its appendages, and most of the vertebrae have a corresponding ganglion for each lateral half, although fusion of two or more ganglia in the successive segments of the cervical region and in those of the coccyx prevents the correspondence from being altogether perfect. In the spinal cord the analogous ganglia of the same segment and the homologous ganglia of successive segments have become so com- pletely integrated that they form a closed tube of gray matter, which extends from the conus medullaris up through the whole length of the ENCEPIIALO-SPINO-XEURAL SYSTEM. 21 cord, the floor of the fourth ventricle, the aqueduct of Sylvius, and the gray matter of the third ventricle, to terminate at the tuber cinereum. One consequence of the fusion of homologous ganglia is that the parts of the cord which correspond to the diiferent segments of the body have undergone considerable displacement. The cord usually ends at the lower border of the body of the first lumbar vertebra- ; but the nerves which descend to pass out through the remaining lumbar intervertebral foramina and through the sacral and sacro-coccygeal foramina, show that the lower part of the cord presides over the functions of the lower segments of the body, although it has by the fusion and approximation of the homologous centres suffered considerable displacement. A still further integration has taken place in the cephalic centres, and the highest ganglia — the cerebrum and cerebellum — consist of large aggregations of gray and white matter, in which it is diflBcult to find any trace of the separate ganglia and the conducting paths of which they are composed. The cephalic ganglia, spinal cord, and peripheral nerves form one functionally indivisible system which may be named the encephalo-spino-neural system. Encephalo-spino-neural System, We shall now make a few general remarks on (1) the arterial supply of this system ; (2) its topography ; (3) its relations to the skeleton ; (4) the topography of the internal parts of the cerebrum, as being the part of the system in which this knowledge is most generally required for practical purposes; and (5) the internal structure of the system. 1. Tlie Arterial Supply, a. The Spinal Arteries. (1) The spinal branches enter the intervertebral foramina along with the roots of the spinal nerves, and are distributed to the vertebrae, spinal membranes, and spinal cord. These arteries are derived from the lateral sacral, ilio-lumbar, lumbar, aortic intercostal, the ascending cervical branch of the inferior thyroid, and vertebral arteries. (2) The anterior spinal artery is a small vessel derived from the vertebral artery near its termination in tlie basilar. This vessel joins with its fellow of the opposite side to form a single vessel which de- scends along the anterior aspect of the spinal cord, and is continued to the lower end of the cord as the anterior median artery. (3) The posterior spinal artery is derived froui the inferior cerebellar 22 ANATOMICAL INTKODUCTION artery ; it winds round the medulla oblongata to reach the posterior aspect of the cord, when it is continued onwards to the cauda equhia. (4) The nutritive arteries of the spinal cord are sufficiently indicated in the annexed diagram (Fig. 1). Fig. 1. la ea a \ m Diagram of the Distribution of the Bloodvessels, and Gbovping or Ganglion Cells in the Spinal Cord. (Young. ) Anterior median artery. (if, Arteries of the anterior median fissure. o, Parieto-occipital fissure. /5, Sulcus orbitalis. oc, Calcarine fissure. T2, Second or middle temporo-sphenoidal convolution. H, Gyrus hippocampi, rs, Third or inferior temporo-sphenoidal convolution U, Gyrus uncinatus. Ti, Gyrus occipito-temporalis lateralis (lobulus fusi- Ch, Optic chiasma. formis). fc, Corpora albicantia. T5, Gyrus occipito-temporalis medialis (lobulus lin- KK, Crura cerebri, gualis . C, Cori)us callosum. 28 ANATOMICAL INTRODUCTION (2) THE CENTRAL OR GAKGLIONIC SYSTEM OF ARTERIES. The ganglionic system form six main groups, which are named the anterior' an'd posterior median (Fig. 3, 1 and 2) ; the right and left antero-lateral (Fig. 8, 3, 3) ; and the right and left posterolateral (Fig. 8, 4, 4). An imaijinary line passing round the circle of Willis, at a distance of two centimetres, would completely surround all these ves- sels, and the area so limited may be called the ganglionic vascular area. Fig. Inner Surface of Riuht Hemisphere. (After Ecker anJ Dueet.) Distribution of Vessels. Tlie regions bounded by the line ( ) represent the territories over whicii the branches of the Ante- rior Cerebral Artery are distributed. I. Is the territory of the Interior mid Ankriur Frontal Artery. II. " " Internal and Middle " " III. " " Internal and Posterior " " The regions bounded by the line ( ) represent the territories over which the branches of the Posterior Cerebral Artery are distributed. II. Is the territory of the Posterior Temporal Artery. Ill- " " Occipital ilrtery . Fissttres and Convolutions. CC, Corpus callosum, longitudinally divided ; Gf, Gyrus fornicatus ; H, Gyrus hippocampi ; h, Sulcus hippocampi ; U, Uncinate gyrus ; cm, Sulcus calloso-marginalis ; Fj, Median aspect of the first frontal convolution ; c, Terminal portion of the sulcus centralis, or fissure of Rolando ; A, Anterior ; B, Posterior central convolution ; Pj", Precuneus ; Oz, Cuneus ; Po, Parieto-occipital fissure ; o, Sulcus occipitalis transversus ; oc, Calcarine fissure ; oc', Superior, oc". Inferior ramus of the same ; D, Gyrus descendens ; T4, Gyrus occipito-temporalis lateralis (lobulus fusiformis); T5, Gyrus occipito-temporalis medialis (lobulus lingualis). EISrCEPHALO-SPINO-XEUEAL SYSTEM, 29 All these vessels are terminal arteries. Some of these branches are of sufficient importance to have been specially described and named. Fig. 6. Outer Surface of the Left Hemisphere. (After KS, 9, 10, 11, 12, 13, 14, as in the preceding figure. Fig. 10. PEnUNCULO-PARIETAL SECTION. (After PlTRES.) 1, Superi( r parietal lobule. 2, Inferior parietal lobule. 3, Sphenoidal lobe. 4, Superior pedunculo- parietal fasciculus. 5, Inferior pedunculo-parietal fasciculus 0, Sphenoidal fasciculus. 7, Coi pus cal- losum. 8 and 10, Caudate nucleus, ii, Optic thalanui:^. EXCEPH ALO - SPIXO - X K U R AL SYSTEM , 41 fissure of Rolando, and cutting the superior and inferior parietal lobules. It is subdivided into superior and inferior pedunculo-parietal and sphenoidal fasciculi (Fig. 16). The last is the occipital section (Fig. 17), in which no separate fas- ciculi are distinguished. Fig. 17. l>(CIPirAI, Sfctiiin. { MtCI rilRES ) 1, Occiiiital convolutions, i, Occipital fasciculi of the centrum ovale. 5. The Internal Structure of the Eneephalo-spino-neural System. The internal structure of the encei)halo-spino-neural system must now be briefly described, and for this purpose we shall divide the sys- tem into (1) the spino-neural, and (2) the encephalo-spinal systems. (1) The Spino-neur-vl System. A spinal segment consists of a disk of nervous matter to each lateral half of which a nerve is attached by an anterior and posterior root, the The Anteriok Surface of the Spinal SEfiMENT, the Anterior Eoot of the Eight Side being Divided. (After Allen Thomson, from Quain.) 1, The anterior median fissure ; 2, Posterior median fissure ; 3, Anterior lateral depression, over which the anterior nerve roots are seen to spread ; 4, Posterior lateral groove into which the posterior roots are seen to sink ; 5, Anterior roots passing the ganglion ; 5', The anterior root divided ; 6, The posterior roots, the fibres of which pass into the ganglion, 6' ; 7, The united or compound nerve ; 7', The posterior primary branch seems to be derived in part from the anterior and in part from the posterior root. latter being furnished with a ganglion (Fig. 18). The gray substance which represents the gangliated structure occupies the central parts of 4-2 ANATOMICAL INTllODUCTION the cord in the well-known shape of the letter H. The median part of the orav substance contains the central canal and the central gray nucle'us of Kolliker, the anterior gray and white commissure lying in Fig. ]0 Section from the Midpi.e of the Cervical Eni-aroemknt ..f the Sri>Ai. Cokd at the Third Month of Embryonic Life. C, Central canal. The other lettei-s indicate the same as tlie conespomling lettei-s in Fig 1. Fig. 20 i, internal ; ganglion cells group. Spinal Cord of a Five-months Human Embryo, from the Middle ok the Cervk.al and Lumbar Enlargements Respectively. (YouNfi ) a, anterior ; a\ antero-lateral ; p/, postero-lateral, c, central, and m, median groups of : 1, ganglion cell of the centre of the antero-lateral group; 2, ganglion cell of the median E X C E P H A L O - S P I N O - X E U R A L S Y S T E :^r Fig. •_'•_'. Fig. 23. Sf.itioks of Spinal Curd of a Xine-moxths Human- Embryo, from tHf, Middle of the Lumbar AND Ceevk'al Enlargements Respectively. (Young.) A, anterior, and P, posterior horns. Tlie small letters indicate the same as in Figs. 20 and 21. The normal size of the .•action from which the di-awing was made is shown above each figure. Fig. 24. Fig. 25. Sections of the Adult Spinal Cord from the Middle of the Lumbar and Ckrvical Enlargements Kespectively. (Young ) The letters indicate the same as those in Figs. 20 and 21. u ANATOMICAL INTRODUCTION. front, and the posterior commissure behind it. The hiteral parts or coluimis consist of an anterior, middle, and posterior part, the first of them representing the anterior, and the Last the posterior gray horn, and the middle chiefly the vesicular column of Clarke. The anterior horns contain large ganglion cells, each of which is furnished with numerous branched processes by means of which it forms definite connections with other cells and fibres. One of these processes is unbranched, and it becomes continuous with the axis-cylin- der of an efierent fibre which passes out through the anterior root and nerve to the periphery. The ganglion cells of the posterior horn are much smaller and less branched than those of the anterior horns, and this horn receives afferent fibres from the periphery of the body. Fio. 20. Fio. 2^ Sections of the Ahui.t Uimax Simnal Cord, from the Upper Cervicai, axd 1J"R.s.vi. Keoioxs Respectively. (Young.) A, anterior, and P, posterior liorns; aa, anterior roots; cc, central canal; ml, the meilio-lateral area. The other letters indicate the same as the corresponding ones in Figs. 20 and 21 The size of the sections from which the drawing was talcen is indicated above each. In Fig. 27, vc represent;* tlio vesicular column of Clarice. In the development of the gray matter of the cord, the groui)S of ganglion cells appear first in the anterior and lateral margins of the anterior horn (Fig. 19), where they form several distinct groups, which are as far as possible removed from the central canal. The gray matter surrounding the central canal represents the growing or embryonic por- ENCEPIIAT.O-SPINO-NEUEAL SYSTEM. 45 tion of tlie gray luuttor, and every new ganglion cell which develops becomes su])eradded at the margins of the first forward groups. The groups of ganglion cells are i)retty constant for the same portions of the c<»rd, but the arrangement varies considerably when sections at different elevations are compared. These groups are represented in the annexed diagrams (Figs. 20-27), and are named the |)Ostero-lateral {pt), the antero-lateral {at), the anterior (a), the internal (/), and the central (c) groups respectively. Another area — the median (m) — contains in tlie adult human cord a considerable number of caudate cells of small size, although they are not aggregated into a distinct group. The cells of the median area, and of the margins of the groups, representing the latest evolved structures, will be the counterpart of the latest evolved functions. The last evolved purely spinal function (not taking into account those regulated from the medulla oblongata) are the complicated movements of the hand, and it may therefore be expected that the median area and the marginal cells will be more fully developed in the cervical enlargement than in any other part of the cord, in the adult cord than in the embryo, and in the hunuin cord than in the cord of animals. This expectation is fully borne out by these facts. A very distinct grouj)ing of ganglionic cells lies in the posterior gray horn near the posterior commissure, named the vesicular column of Clarke (Fig. 1, ve). So far we have only spoken of one segment of tlie cord, but the gray matter of the different segments has become integrated to such an extent that it forms, not a series of ganglia like the sym])athetic sj^stem, but a continuous tube. The central gray tube opens at the calamus sci'iptorius into the fourth ventricle, while higher up it is represented by the aqueduct of Sylvius, and then opens into the third ventricle. In the medulla the groups of ganglion cells ha\'e undergone an exten- sive rearrangement. The main grouj) of the anterior horns is repre- sented by the nuclei of origin of the hyi»oglossal nerve (Fig. 2, ^', a, ah pi), but a portion of the antero-lateral and ])ostero-lateral groups have become detached from the rest of their groups, and are aggregated in the formatio reticularis in two tolerably distinct groups, the anterior and posterior nuclei of the lateral column of the medulla (Fig. 2, ale, pic). The median area and the nuirginal cells are represented by a much larger ao-o-regation of cells than anything to be found in the cord, and constitute groups which may be named the internal accessory (Fig. 2, if) and the external accessory nuclei (Fig. 1, ef) of the facial nerve. These groups of cells are probably the structural counterparts of mimetic facial and articulatory movements. The vesicular column of Clarke is only represented in the dorsal region of the spinal cord. It contains bipolar ganglion cells, and cells 46 ANATOMICAL INTRODUCTION. of similar character are to be found in the nuclei of the vagus (Fig. 2, nv) and glosso-pliaryngeal nerves, and it is therefore probable that the nuclei of these nerves are, to some extent at least, the representa- tives of the vesicular column of Clarke in the medulla. Fig. 28. Section of the Meduli,.\ Obuin(:.\ta on a levkl with the supbrfici.\t. orkmn of the Acoustic Nerve. (Modified from Flechsig.) E vm, Boot uf the acoustic nerve. VIII, Posterior median acoustic nucleus Tin", Posterior lateral acoustic nucleus. H, Nucleus of the hypoglossal nerve. ip, Internal division of the inferior peduncle of the cerebellum. ep, External division of the inferior peduncle of the cerebellum. frs, Forniatio reticularis. a, Arciform iibres. The posterior gray horn is represented in the medulla by the sub- stantia gelatinosa (Fig. 2, sg). In addition to the sensory nuclei of common sensation represented by the substantia gelatinosa, the medulla oblongata contains special sensory nuclei. It is probable that part of ENGEPHALO-SriNO- NEURAL SYSTEM. 47 the nuclei of the gh)8so-i)haryiige!il nerve, and probably also of the fifth nerve, reiiresent the special nerves of taste; four nuclei, namely, the posterior median (Fig. 28, Viii), the posterior lateral the anterior median, and the anterior lateral acoustic nuclei, represent the auditory nerve; Avhile the corpora quadrigemina and the internal geniculate body repre- sent the nuclei of origin of the optic nerve. The spinal ganglia, situ- ated in the })Osterior roots of each pair of nerves, belong to the spinal system. The casserian ganglion is the representative of these ganglia in the cranial end of the spinal system. The middle sensory nucleus of the trigeminus is also in structure very similar to the ganglia of the posterior roots, and it also is probably the homologue of the spinal ganglia. The external geniculate hody likewise contains cells which are very like those of the ganglia of the posterior roots, and it must possibly be regarded as a ganglion for the optic nerve homologous with the spinal ganglia. «/* Transversje Section of the Cervical Part or the Spinal Cord of a Human Embryo of six weeks. (From KoLLiKER.) c, Central cuiial ; e, e', Its eiiithelial lining ; g, Gray substance ; ar, Anterior roots ; pr, Posterior roots ; a, Anterior root-zones ; p, Posterior root-zones. The white substance of a sjiinal segment is divided anatomically by the anterior and posterior median fissure, and the nerve roots into an anterior, lateral, and posterior column for each lateral half. A small portion only of this white substance really belongs to the spinal system, the remainder representing conducting paths between the portions of the cord below, or posterior to the segment examined, and the encephalic ganglia. This purely spinal portion of the white substance consists of the portions named the anterior and jyosterior root-zones. As might be expected, these areas are the first portions of the white substance to 48 ANATOMICAL INTRODUCTION. | appear in the development of the cord, anasses down the same side and supplies the muscles m^ and m^ on the left side of the body S, S', sensory areas on the left side of the body ; 3', 3, the main sensory tract from the left side of body ; it passes up on the opposite side (right) of the cord in the postero-external column, and proceeds to the right hemisphere of the biain ; S-, S^, sensoi'y areas of the right side of the body ; •!', 4, the main sensory tract from the right side of the body, proceed- ing up the left side of the cord to the left hemisphere of tlie brain The arrow;^ indicate the direction of the conductiim. between the caudate nucleus and optic thalamus on the inner, and the lenticular nucleus on the outer side, but without forming any connec- 62 ANATOMICAL INTRODUCTION. tions with these ganglia, and pass still as one bundle through the middle third of the crusta of the crus cerebri. On reaching the pons the fibres become separated into several bundles by the transverse fibres of the middle peduncle of the cerebellum, but on reaching the medulla oblono-ata they come together again and form the anterior pyramid of the medulla, and it is from this circumstance that they are named the pyramidal tracts. At the lower end of the medulla by far the largest portion of the anterior pyramid crosses over to the lateral column of the opposite side after decussating with the corresponding fibres of the anterior pyramid. A few of the fibres which lie on the external aspect of the anterior pyramid pass onwards in the anterior column of the spinal cord without crossing, and these form the columns of Tiirck. (b) The Sensory Conducting Paths. — The fibres of the posterior nerve- root diverge like a fan immediately on entering the spinal cord (Fig. 37, pr', pr"), and most if not all of them cross over to the opposite side (Fig. 38, S S'^), and then ascend to reach the cerebral cortex chiefly of the occipital and temporo-sphenoidal lobes. The course of these fibres is not well ascertained at all the intermediate points. It is probable that in the spinal cord some of these fibres ascend in the posterior gray horn, and others in the postero-external column. Some anatomists believe that a portion of the sensory conducting path ascends in the cord on the same side as the root from which it is derived, and that a supplementary decussation of sensory fibres takes place in the medulla oblongata (Fig. 32, S). It is, however, very doubtful whether such a supplementary decussation exists, and patho- logical observations would at least seem to indicate that the sensory conducting paths belonging to the opposite side of the body pass through the restiform body of the medulla oblongata. These fibres pass upwards in posterior and external bundles of the longitudinal fibres of the pons and come together to form one bundle in the ex- ternal third of the crusta (Fig. 32, ps). The fibres ascend as one bundle on the posterior third of the posterior segment of the internal capsule, and at this point they are joined by fibres which ascend from the optic tracts through the geniculate bodies and anterior tubercle of the corpora of the quadrigemina around the optic radiations of Gratiolet, and also by fibres from the olfactory tracts of the opposite side, which reach them most probably through the anterior commissure of the third ventricle and the optic thalamus. The sensory fibres of the internal capsule now radiate backwards, outwards, and upwards to reach the cortex of the occipital and temporo-sphenoidal lobes, and to a less extent ) Avhich renders seizure of it or escape from it beneficial. Within the organism there is (c) the impression or sensa- tion Avhich the property a produces, serving as stimulus, and there is connected Avith it the motor change {d) by which seizure or escape is effected. Now, psychology is chiefly concerned <\ith the connection between the relation ab and the relation cd, under all those forms which they assume in the course of evolution. Each of the factors CEREBRO-SPINAL SYSTEM". 69 and each of the relations grows more involved as organization advances. Instead of being single, the identifying attribute a often becomes, in the environment of a superior animal, a cluster of attributes, such as the size, form, colors, motions, displayed by a distant creature that is dangerous. The factor 5, with which this distant combination of attri- butes is associated, becomes the congeries of characters, powers, habits, which constitute it an enemy of the subjective factors ; c becomes a complicated set of visual sensations coordinated with one another and with the ideas and feelings established by experience of such enemies, and constituting the motive to escape ; while d becomes the intricate, and often prolonged, series of runs, leaps, doubles, dives, etc., made in eluding the enemy." The account first given of reflex and psychical action shows that the former consists of a muscular adjustment made in response to ?l pi-esent impression ; while the latter is a muscular adjustment excited by a present impression, but made to attain or avoid an anticipated impres- sion. In reflex action the muscular adjustment is effected by means of afferent and eff'erent fibres and one centre, while in psychical action this mechanism must consist of at least afferent and efferent fibres, a recep- tion and an emission centre with some means of intercentral communi- cation. In the purely unconscious psychical actions, or the instinctive actions, the optic thalamus is supposed to be the central receptive organ, and the corpus striatum the central emission organ, the two being con- nected 1)7 white fibres which interlace with the longitudinal filires of the internal capsule. The cortex of the cerebrum with its afferent and efferent fibres appears to be the organ for the regulation of the con- scious psychical actions, although the fact that individuals sometimes sing songs or recite long passages of poetry during the unconscious stage which follows an epileptic attack, or that which results from the mesmeric state or from chloroform narcosis, seems to show^ that all ac- tions, which, like spirits, are regulated from the cortex of the brain, are not necessarily attended by consciousness. A glance at the structure of the cortex of the brain (Fig. 30) will show that the small cells of the outer layers are best adapted to act as a receptive organ, while the caudate cells of the inner layers are best adapted to act as an emissive centre. The structure of the outer layers of the cortex in comparison with the inner layers, forcibly reminds one of the structure of the pos- terior gray horn of the spinal cord in comparison with that of the anterior horn. In the outer layers of the cortex, as in the posterior gray horn, the afferent fibres terminate without forming definite con- nections with the cells, which are in both cases, small, round, and desti- tute of processes, while in the inner layers of the cortex and in the 70 PHYSIOLOGICAL INTEODUCTION . anterior gray horns, the cells, which are large and furnished with numerous processes, are definitely connected with the axis-cylinders of efferent fibres. Now, although it is probable that the outer layers of the cortex of the whole cerebrum constitute a receptive organ, and the inner layers an emissive organ, yet, the outer layers of certain districts of the cortex have become specially adapted to act as receptive organs or sensory centres, and the inner layers of other districts have become specially adapted to act as emissive organs or motor centres. (1) The Sensory Cortical Centres. — From his first experiment, Ferrier concluded that the centre for vision was situated in the angular gyrus and surrounding gray matter; the auditory centre in the superior temporo-sphenoidal convolution ; the centres of taste and smell at the extremity of the temporo-sphenoidal lobe, and that of touch in the uncinate gyrus and the hippocampus major, Munk believes that the visual centre or area is of much larger extent than that assigned to it by Ferrier, and that it is situated in the occipital lobes. He maintains that removal of this area causes Ijlindness, and that extirpation of small portions of it gives rise to blindness of localized areas of the retina. He beheves that there are three visual spheres in the cortex corresponding to three visual areas in the retina. The external part of the retina of the left eye is connected with the external part of the cortical visual centre in the left hemisphere, while the internal and central portions of the retina of the right eye are respectively connected with the internal and central portions of the visual centre of the left or opposite hemi- sphere. The upper portion of the retina is connected with tlie front, and the lower part with the posterior aspect of the visual centre of the opposite hemisphere. Removal of both visual centres causes, according to Munk, complete or absolute blindness, while partial removal of these areas causes incom- plete, or what Munk calls psycliical blindness, a state of vision first observed by Goltz, in which the animal sees and avoids objects, but fails to recognize the special properties of a piece of meat, for example, which renders it food to be eaten instead of an obstacle to Ije avoided. Munk regards the whole superior and internal surface of the cerebral hemisphere as constituting a sensory area, and the annexed diagrams (Fig. 40) indicate the manner in which he believes these centres to be distributed. Very elaborate experiments have been conducted by Drs. Ferrier and Yeo, to determine the exact seat of the centre of vision, and the most important conclusion they come to is that " destruction of both angular gyri and occipital lobes causes total and permanent blindness in both eyes without any impairment of the other senses or of motor CEREBRO-SPIXAL SYSTEM. 71 ])Ower." Blindness or heniiopia Avas caused by less extensive injuries, but partial or complete recovery ahvays ensued. The experiments of Luciani show that visual disturbances follow extirpation, not only of the occipital, but also of the parietal, temporal, and frontal lobes. It may therefore be concluded that the localization of sensory centres is a diffused one, and that the whole surface of the cortex is possessed of more or less of sensory functions. Fig. 40. Upper Sueface of the Brain of the Monkey. (After Munk.) Senxory Areas : A, of the eyes; B, of the ears ; C, of the sensibility of the lower extremitj' ; D, Anterior extremity ; E, Head ; F, Ocular mu.scular apparatus ; G, Region of ears ; H, Neck ; I, Body. (2) The Motor Qortical Centres. — The experiments of Hitzig and Fritsch, Terrier, and others have shown that stimulation of certain po'-tions of the cortex of the cerebral hemispheres by electrical currents is followed by associated muscular movements of the opposite half of the body. The portion of the cortex which is thus excitable is named the motor area. This area corresponds generally with the ])art supplied by the Sylvian artery, and also with the area in which the giant cells, already described, have been discovered. The portions of the cortex — the areas supplied by the anterior and posterior cerebral arteries — which do not respond to electrical excitation are called latent areas. It has also been found that extirpation of a localized portion of the motor area causes paralysis of the muscles which are thrown into a state of spasm by electrical excitation of this portion. The annexed diagrams (Figs. 41 and 42) show the topographical distribution of these motor centres on the outer and superior surfaces of the cerebral hemispheres without further description. The experiments of Schafer and Horsley 72 PHYSIOLOGICAL INTRODUCTION. have shoAvn that a p(3rtion of the cortex of the internal surface of the cerebral hemisphere is excitable. The excitable portion is limited to the marginal convolution, and extends as far forwards as the junction of the middle and posterior thirds of the superior frontal convolution, and as for backwards as a point opposite the centre of the parietal lobule. Speaking in general terms, stimulation induces contractions of the muscles of the trunk and of the large muscles inserted in the j^houlder-blade and shoulder, and those inserted about the hip-joint. Fig. 41. Figs. 41 and 42.— Sihe and Upi'eu Views of the Bkain of Max. (After Ferkier ) These figui'es are constructed by marking on the brain of man, in their respective situations, the motor areas of tlie brain of the monkey as determined by experiment, and the description of the effects of stimu- lating the various areas refers to tlie brain of the monkey. 1 (On the posterior-parietal lob\ile\ Advance of the opposite hind limb as in walking. 2, 3, 4 (Around the upper extremity of the fissure of Rolando), Complex movements of the opposite leg and arm, and of the trunk as in swimming, a, 6, c, d (On the ascending parietal convolution). Individual and combined movements of the fingers and wrist of the opposite hand. Prehensile movements, o (At the posterior extremity of the superior frontal convolution\ Extension forward of the opposite arm and hand. 6 (On the upper part of the ascending frontal convolution). Supination and flexion of the opposite forearm. 7 (On the median portion of the ascending frontal convolution >, Retraction and elevation of the oppo- site angle of the mouth by means of the zygomatic muscles. 8 (Lower down on the same convolution), Elevation of the ala nasi and upjier lip with depression of the lower lip on the opposite side C E R E 1 5 R - S P I N A L S Y S T E :N[ . rs (o) Tlw Intireentral Connections. — The central ends of the indi- vidual sensory mechanisms are unified 'bf a collective centre — the sen- sormm commune — which is the general centre of nervous connections on the afferent side. It may also be supposed that the individual motor centres are unified by a general centre of nervous connections which may be regarded as a motorium commune. Between the sen- FiG. 42. 0, 10 (At the inferior extremity of the ascending frontal and posterior extremity of the third frontal convolution), Opening of the mouth with (9) protrusion and (10) retraction of the tongue. Region of Aphasiu. 11 (At the inferior extremity of the ascending parietal convolution), Eetraction of the opposite angle of the mouth, the head turned slightly to one side. 12 (On the posterior portions of the superior and middle frontal convolutions), Eyes opening widely, pupils dilating, and the head and eyes turning towards the opposite side 13, 13' (On the supramarginal lobule and angular gyrus). The eyes moving towards the opposite side- with an upward (13; or downward (13') deviation. Pupils generally contracting. (Centre of Vision.) 14 (On the inframarginal or superior temporo-.sphenoidal convolution), Pricking up of the opposite ear, head and eyes turning to the opposite side, and pupils dilating largely. (Centre of hearing.) Ferrier, moreover, places the centres of taste and smell at the extremity of the temporo-sphenoidiil lobe, and that of touch in the gyrus uncinatus and hippocampus major. 74 PHYSIOLOGICAL INTRODUCTIOX . sorium commune and the motorium commune there is no distinct line of demarcation, nor is there any definite boundary between these hio-hest centres and the individual sensory and motor centres. All of them run indistinguishably into one another, and all of them are rep- resented bv the cortex. The activity of the individual sensory centres is the con-elation of sensation and feeling, and of the highest sensory centre of perception — emotion, and the highest operation of the intel- lect, while the activity of the motor centres is the correlation of con- scious exertion and the will. But although the molecular activity of the cortex of the brain is the correlative of consciousness, all parts of the cortex do not stand in e(iual relation with feeling. It seems to me that consciousness is correlated in a special manner with the activity of the small cells, which are destitute of processes and definite connections. When an unaccustomed impression is made upon the surface of the body the impulses are conducted inwards to the small cells of the outer layers of the cortex, and the energy set free by the unusual disturbance is in great part expended in producing a new organization amongst these cells, and it is during the progress of this organization that psychical action is attended by the highest consciousness. But in proportion as this impression becomes frequently repeated in experience, the organi- zation of the cells becomes more and more complete by the establish- ment of new connections, and after a time the channels of communica- tion between the receptive and emissive organs become so open that the muscular adjustment follows the impression promptly and in almost a wholly unconscious manner. The degree of consciousness which attends a particular operation may, therefore, be regarded as an expres- sive indication of the resistance offered to the molecular movements or impulses in passing from the central receptive to the central emissive organs. Nor is this all. It is very probable that the part of the centre which is most remote from both the sensory and motor centres will, durintr its activity be correlated with the highest consciousness. This part is what is called the praefrontal area of the coi'tex, and the fact that consciousness is lost at a much earlier period in epileptiform attacks caused by lesions of this area than in the attacks which are caused by lesions in other areas of the cortex, speaks much in favor of the supposition just advanced. The different cortical sensory and motor centres are connected with one another in various ways by systems of white fibres. These SA'stems are the longitudinal or collateral fibres, consisting of the arcuate fibres or fibrse proprise, fibres of the gyrus fornicatus, longitudinal septal fibres, tlie fasciculus uncinatus, the longitudinal inferior fasciculus, the longi- tudinal fibres of the corpus callosum, and the perpendicular occipital CEREBELLO-SPINAL SYSTEM. 75 fasciculus described by Wernicke, and the transverse or commissural fibres, wliicli connect similar points of the convolutions of the two hemispheres, and which consist of the transverse fibres of the corpus callosum, and the fibres of the anterior and posterior commissures of the third ventricle. 4. FUNCTIONS OF THE CEREBELLO-SPINAL SYSTEM. The cerebellum must, like the cerelirum, act on the muscular svstem through the spinal cord and peripheral nerves. The central gray tube, as we have seen, forms with the peripheral nerves a system of simple coordination in time, and we now find that it likewise forms a system of simple coordination in space (reflex tonus) ; the intermediate ganglia of the cerebello-spinal system acting on the central gray tube and peripheral nerves form a system of compound coordination in space (maintenance of unvarying attitudes), and the cortex of the cerebellum acting on the inferior centres forms a system of doubly compound coordination in space (the adjustment of the tonic contractions of the muscles rendered necessary by changes of attitude). If now tlie cere- bellum is an organ for producing a balanced state of contraction of the muscles in the maintenance of attitudes, it may be expected that injury of this organ will cause a loss of this balance and a conse(|uent diffi- culty in maintaining complex attitudes. Flourens was the first to observe the effect of injuries of the cerebellum on the maintenance of attitudes, or on equilibration, as it is called. He found that when a small portion of the cerebellum was removed from a pigeon, the animal's gait became unsteady, and that when larger portions were taken away, the movements became very disorderly. Experiments on animals have also shown that section of the middle peduncle of the cerebellum is followed by a forced movement of the body in which the animal rolls round its longitudinal axis, the rotation being generally towards the side operated upon. Injury of the lateral lobe of the cerebellum, and probably of the fibres of the peduncle as they pass transversely through the pons, produces the same kind of forced moyeiaent as section of the middle peduncle. Nothnagel concludes from experiments on rabbits that lesions which injure the fibres uniting the two sides of the organ occasion the greatest amount of motor disturbance. Ferrier found that electrical stimulation of the cortex of the cerel)ellum in animals caused movements of both eyes with associated movements of the head, limbs, and pupils. Our relations to the external objects in space are largely determined by the sense of vision, which is better adapted than any of the other senses for conducting a large number of simultaneous impressions from the periphery to the centres, and it may consequently 7(3 PHYSIOLOGICAL INTKODUCTION . be expected that the organs of vision will stand in a peculiarly intimate relation to the chief organ for regulating the attitudes of the body. The semicircular canals, with the portion of the auditory nerve which supplies them, appear to form a special peripheral organ for determining the attitudes of the body through the cerebellum. 5. COOPERATION OF THE CEREBRO-SPINAL AND CEREBELLO- SPINAL SYSTEMS. According to the theory which has just been advanced the multitu- dinous adjustments of the body, both in time and space, are regulated by the combined action of the cerebrum and cerebellum acting through the spinal cord and peripheral nerves. The cooperation of these organs in the regulation of motor actions is, however, generally of an antagonistic Fig. 43 CL" a' a Schema of Encephalo-spixal Action. 8, Motor ganglion cell of spinal cord ; c, Ganglion chH of cortex of cerebrum, and d , of cortex of cere- bellum ; o, o', a", Afferent fibres to the spinal cord, and to the cortices of the cerebrum and of the cere- bellum respectively ; e, e, Efferent fibres from the spinal ganglion cell to m, »n', the muscles ; e' and e", Fibres from the cerebral and cerebellar cells respectively to the spinal ganglion cell ; i, Intercentral filire connecting the cerebral and cerebellar cells. The arrows indicate the direction of the conduction. kind. The cerebellum tends to maintain an unvarying attitude, Avhile the cerebrum, in initiating a change of attitude, must act by overthrowing the balance of the muscular contractions which maintain this attitude. The overthrow of this eciuilibrium can Ije effected by the cerebrum in CEREBKO-SriNAL AXD CE R E BE LLO - SP IX AL SYSTEMS. 77 either of two ways, either positively by an increase of nervous impulses to certain groups of muscles, or negatively by arresting or inhibitino- in the spinal centres the cerebellar influx to their antagonists. Now it is manifest that the latter method would be much more economical than the former, and consec^uently there is every reason to believe that the cerebrum does act largely by inhibiting the action of the cerebellum, although it is also certain that it must exercise a positive control over the various muscular contractions. The conjoint action of the central gray tube, the cerebrum, and cerebellum is represented in the accom- panying diagram (Fig. 43) under the simplest conditions. A ganglion cell of the spinal cord is represented by s, of the cerebrum by c, of the cerebellum by c'. The afferent conducting paths from the periphery to the spinal cord, cerebrum, and cerebellum are represented by a, a\ a" respectively. The efferent conducting path between the cerebrum and spinal cord is represented by e', between the cerebellum and cord by e", and lietween the cord and muscles l)y e, while m m represent the mus- cles themselves, and the arrows indicate the direction of the currents. Now, when an impression is made upon a, it is conveyed to .s, and reflected through e e to m m, this constituting a simple reflex action. When an impression is made upon a", the impulse is conveyed to c' and through e" to s, and through e e to m m, producing a continuous contraction of the muscles. But when an impression is made upon a', an impulse is conveyed to c and dowuAvards, through e to s. Now, the impulses conveyed through e' to s may produce, Avhen of a certain degree of intensity, only an arrestive or inhibitory action on the im- pulses conveyed to s through a and e", while an additional degree of intensity enables it to pass through s and e s, the muscles of the buttocks, although stronglv contracted in effecting the erect position, do not require to contract in order to maintain it. The muscles of the calf, those of the front of the thigh, and the erector spinne are therefore the most active muscles in maintaining the erect posture, and these are, according to the hypothe- sis, maintained in a state of tonic contraction, mainly by the cerebellum. (b) Walking. — At each step in w'alking there is a moment at which the body rests vertically on the foot of one leg (say the right), Avhich is then called the '■'■active leg." The other (left), which is now called the ^'■passive leg," is at this time inclined obli(^uely, Avith the heel raised and the toe resting on the ground. The left leg, slightly flexed to avoid contact with the ground, is now swung forwards like a pendulum, the length of the swing or step being determined CEREBRO-SPINAL AND CEEEBELLO - SPIN AL SYSTEMS. 79 by the length of tlie leg, the left toe is brought to the ground, and the step is finished. The left leg, Avhich was previously passive, now gradually becomes straight and rigid, and the body is moved forwards <»n the left toe as a fulcrum ; while the right leg, which was previously at-tive, assumes an inclined position, with the heel raised and the toe resting on the ground, so that it is ready to swing forwards, and then once more to assume the role of activity, while its fellow becomes in its turn passive again. During the forward movement the centre of gravity of the body describes a curve, the convexity of which is up- ward ; hence in successive steps the centre of gravity, and with it the {(>]) of the head, describes a series of curves, with their convexities upwards. In standing on Ixjth feet the line of gravity falls betAveen them, )jut in walking it must be alternately shifted from one foot to the other, in order to balance the body on the active leg. While the left leg, for instance, is passive and swinging, the line of gravity falls within the area of the right foot, and passes through the right lateral half of the pelvis, and as the left foot becomes active the centre of gravity is shifted to the op])osite side, and the line of gravity passes through the left lateral half of the pelvis to the left foot. In walking, therefore, the centre of gravity describes not only a series of vertical but also a series of horizontal curves, so that the curve described by the head is composed of vertical and horizontal factors. In slow walking there is an appreciable time during which both feet are on the ground ; the one being planted so as to become active before the other has ceased its activity. In fast walking this period is very short, the one leaving the ground the moment the other touches it, while in running there is an interval during which neither foot is on the ground. Let us now attend to the muscles, the contraction of which effects the changes of attitude necessarily involved in walking. Suppose that we start with the right leg in the vertical position, with the line of gravity passing within the line of the right foot, and the left partially raised from the around. The first indication of a forward movement must be eff"ected by a contraction of the flexors of the foot on the leg, which, as the toe is fixed, bends the leg and with it the whole body forwards. This contraction fixes the upper end of the tibia, the leg being bent forwards at an acute angle with the foot, and the femur is kept extended on the tibia by a rigid contraction of the muscles of the front of the thigh. The lower end of the femur and upper end of the tibia are now rendered fixed points, the line of gravity is rapidly passing forwards from the middle of the foot to the toe, the weight is thus taken off" the heel, and contraction of the muscles of the calf causes its elevation. }iO PHYSIOLOGICAL IXTRODUCTIOX. But tlie line of gravity is now passing through the toe, in front of the knee, and in front of the centre of the hip-joint, so that the muscles of the back of the thigh and those of the buttocks must contract strongly or the body would be flexed on the thighs, while the erectors of the spine must be sufficiently contracted to keep the different segments of the body in a rigid condition. It is manifest that as soon as the line of p-ravity passes in front of the centre of the hip-joint and through the toe, although muscular action may maintain the different segments of the body extended, no muscular action can prevent the body as a whole from falling forwards on the toe as a pivot, and the body would fall unless the left foot were now in a position to be planted on the o-round in front of the line of gravity, and ready to assume the role of the active leg. Before, however, the left leg can become active, the line of gravity must be transferred to the left foot, and before the right foot can be made to swing it must be shortened so as to avoid contact with the ground. These operations are so im])ortant as to require care- ful study. (c) The transference of the centre of gravity from the passive to the active leg is largely effected by the contraction of the abductors of the thigh, especially by the gluteus medius, contraction of which, the left thigh being fixed, causes the pelvis to rotate vertically on the hip- joint; so that the centre of gravity, and with it the head, describes a curve to the left, with its convexity upAvards, a movement which at the same time slightly elevates the pelvis and Avith it the hip-joint of the opposite side. The slight elevation of the right hip-joint not only transfers the centre of gravity to the left, but also increases the distance of the centre of movement (hip-joint) of the passive leg (right) from the ground, and thus prepares for the forward SAvinging of the right leg. The contraction of the abductors is accompanied by a contraction of their antagonists — the adductors, Avhich not only gives steadiness to the pelvis but holds the latter in I'eadiness to counteract at once any tendency to overaction on the part of the former, by Avhich the line of gravity Avould be carried beyond the middle of the foot. The curve described by the head OAving to contraction of these muscles Avould indeed be much greater than \l is Avere it not compensated by contrac- tion of other muscles. At the time that the abductors of the left leg con- tract, and thus rotate the pelvis, the centre of gravity, and head to the left, the erector spinee of the right side enter into a somcAvhat additional contraction producing a compensating curve to the right, so that the head does not deviate to the left during the transference of the centre of gravity to the left foot to anything like the extent that might l)e expected. CEEEHRO-SPIXAL AXD C E 1! E 15ELL0 - S ]' 1 X AL SYSTEMS. bl (d) Sivinginti of the Passive Leg. — It lias just been said tliat Avlien the left leg becomes active the pelvis rotates vertically on the left hip, so that the opposite hip-joint is slightly elevated to an extent sufficient to take the weight of the body from the right toe, but inasmuch as the right foot is, at the time it is about to become passive, extended ob- liquely, with the toe depressed, while the left is placed nearly vertically, the former is much too long to swing past the other without touchino- the ground, and the slight vertical rotation of the pelvis just described does not give the requisite elevation for this purpose. In order to swing forwards, therefore, the right leg is still further shortened bv flexion of its various segments on the body and on one another. The thigh is slightly flexed on the body, the leg on the thigh, and the foot on the leg. Of these movements the slight elevation of the toe caused by dorsal flexion of the foot is by far the most important and special ; it is this movement which distinguishes the walk of the adult from that of the infant, the latter advancing the passive foot not by a pendulum motion, but by a voluntary eifort in which the leg and foot are raised from the ground by the flexion of the thigh on the body. It may also be mentioned that the adductors of the thigh manifest a very special action in assisting to cross one leg over the other — an action which cannot be effected by the lower animals, or by the human inflint, and hence these muscles must also be regarded as being in an esjiecial manner under cerebral influence. The cerebro-spinal influence is therefore manifested in the active leg during locomotion by securino- a strong contraction of the anterior flexors of the foot, and of the flexors of the leg on the thigh along with the abductors so as to fix and rotate the pelvis vertically, while it is manifested in the passive leg partly by con- traction of the flexors of the thigh on the body, partly by contraction of the flexors of the leg on the thigh, and partly by flexion of the foot on the leg, the flexion in all these instances being ])robably due less to active contraction than to relaxation of the antagonistic muscles. The transference of the line of gravity to the active leg also takes part in this action by removing the fixed point, from which the muscles of the passive leg act, from the foot to the pelvis. (e) The Act of Acquiring the Erect Posture. — Now, if the changes of position which take place in walking are due to the predominance of cerebro-spinal over cerebello-spinal action, this is no less true with respect to the successive changes of posture requisite to raise the body from the recumbent to the erect posture. Suppose a man is lying in the prone position, and then gets up on his hands and knees. When the knees are raised by muscular action, so that the body is supported by the tips of the fingers and the toes, while the centre of gravity falls 6 e said to regulate the accessory functions in a peculiar sense. The accessory structure constitutes indeed a new complexity of mechanism superadded to that already existing, a complexity rendered necessary for the regulation of the intricate and multiform actions Avhich distinguisli man from the lower animals. In the develo])ment of the accessory system, small round cells and non-medullated fi])res appear at a comparatively late period in the development of the embryo, and the presence of these simple elements may be regarded as the structural counterpart of a new modification or specialization of function. Specialization of func- tion has hitherto been connected with the gradiuil development of medullated from non-medullated fibres, and of large caudate fi'om small round cells ; but now it appears that specialization of function is to be connected with the development of embryonic cells and fibres. There is, however, no contradiction between the two statements. The em- bryonic cells and fibres of the accessory system do not of themselves indicate any specialization of function. I'hese cells and fibres are, indeed, mere complications of an already existing mechanism, and it is this alone which entitles them to be regarded as true indicators of a newly acquired specialization of function ; they are, in short, mere modifications of an already existing structure corresponding to newly acquired modifications of previously existing muscular adjustments. There can 1)e no doubt that the fundamental and accessory portions of the nervous svstem will be so min";led together that it will be almost impossible to separate the two, but whether they can be distinguished from one another morphologically or not, the mental distinction is a CKRl-:i?R()-SI'IXAI, AXD CE R EBELLO - SP IN AL SYSTEMS. 85 valuable one, and it -will Ije found of importance to remember that in man the cephalic ganglia, the central gray tube, the conducting paths, and even the peripheral nerves, Jimst contain fundamental and accessory cells and fibres. A comparison of the brain of man Avith that of the monkey will afford a rough test by which we may distinguish the accessory portions of the former of the two. Passing over such obvious considerations as distinctions of size and weight, the first important difference we note is the great relative increase in the size of the frontal lobe in the brain of man. The relative increase of this lobe causes the posterior lobes to be thrust further backwards over the cerebellum, the fissure of Rolando to slant upwards and backwards instead of being vertical, as in the brain of the monkey, and the posterior limb of the Sylvian fissure to become longitudinal instead of slanting upwards, as in the Simian brain. It is likely that the large relative size of the frontal lobe in num is connected with his mental superiority over the monkey. The next difference we observe is the depth of the fissures in the brain of man as compared with that of the monkey. In the course of develop- ment the summits of the convolutions are first formed, and they alone are directly connected with the incoming and outgoing fibres of the cerebro-spinal conducting paths. The infolding of the cortex, which forms a sulcus, is a later result of development, and, as the superficial extent of the cortex becomes greater and greater, the deeper the sulci become, so the depth of the sulci may be taken to some extent as a measure of the development of the brain. The next point we note is the great complexity of the arrangement of the convolutions in the brain of man as compared with that of the monkey. The convolutions of the human brain are divided into primary or fundamental and st'condary or accessory. The fundamental convolutions in man are distributed along the margins of the great longitudinal fissure and other primary fissures, like the Sylvian fissure and the fissure of Rolando, and their disposition corresponds closely with the arrangement of the convolutions in the brain of the monkey. The accessory convolutions of man, which are rather irregular in their distribution, may be re- garded as structures superadded in the course of evolution. These convolutions are connected with the primary convolutions by arcuate fibres, and are not directly connected with the ascending and radiating fibres of the internal capsule, and consequently their activity is likely to be correlated with mental operations. Another remarkable feature in which the human brain diff"ers from the brain of animals is the manner in which the Island of Reil is completely surrounded and hidden out of view by deep convolutions. This is brought about by 80 PHYSIOLOGICAL INTRODUCTION, the large development of the posterior extremity of the inferior frontal, of the Inferior extremities of the ascending frontal and parietal convo- lutions, and of the supra-marginal, angular, and temporo-sphenoidal gvri. The consequence of the large development of these convolutions is that the cortex is deeply folded over the Island of Reil, this fold forming a kind of hood, which has been named the operculum. It ap- pears to me that the cortex of the Island of Reil, starting from the gray matter of the anterior perforated space, is the embryonic part of the cortex of the brain, just as the central gray column is the embryonic Tig. 4;'!. Horizontal Section ok the Basal Ganglia and Inteksal C'apsvle of a Nine .Months' Kmbrvo. II, in, Second and third segments of the nucleus respectively ; NC, Caudate nucleus ; TH, Optic thalamus ; IN, Island of Keil ; ps, Peduncular sensory tract and optic radiations of Gratiolet ; P, Fnndii- mental, P', Mixed, and^), Accessory portion of pyramidal tract ; C, Fibres from the corpus callosum i?). portion of the gray matter of the spinal cord. On the supposition that the portion of the Island of Reil which lies in the line of distribution of the Sylvian artery is the embryonic portion of the convolutions of the motor area of the cortex, it may be expected that the earlier formed portions of these convolutions will be thrust upwards towards the great longitudinal fissure, while the later formed pin-tions will approach nearer and nearer to the root of the artery. According to this supposition,, therefore, the fundamental portions of the convolutions supplied by the Sylvian artery Avill be found near the great longitudinal fissure, and the ("KRKBKO-SPIN AL A X D (' K R K ]5ELL0 - S P 1 N A L SYSTEMS. 87 accessory portion low down near the root of the artery, the hast portion being formed by the o))erculum. This opinion corresponds closely with the topoii-raphical distribution of the motor centres as determined l)v experiment and i)atliological observation. The movements of the mus- cles of the trunk, which must be regarded as the fundamental move- ments, are regulated from the marginal convolutions of the longitudinal Fio. 4)). P/ — Tkansveksf, Section oi- iHh < ui:- Cerebri on a level with the anterior pair of Corpora QUADRKiEMINA, FROM A NINE MONTHS' EMBRYO. (Modified froill KraUSE.) ff, cnista ; P, pyrnniidal tract ; p, accessory portion of tlie pyramidal tract ; LN, locus niger ; BK, reil nuclous of the tegmentum ; L, posterior longitudinal fasciculus ; or and ar', upward continuation of the internal and external portions respectively of the anterior root-zone of the spinal cord ; iii, third nerve ; in', nucleus of the third nerve ; iv, fourth nerve ; iv', nucleus of the fourth nerve : iv", crossing of the fibres of the fourth nerve to opposite sides; rf/, descending root of the trigeminus; cc, aqueduct of Sylvius ; X, crossing of the fibres of the superior peduncles of the cerebellum ; pf, fasciculus of meduUated fibres proceeding from the fillet tn the anterior pair of corpora i|uadrigemiiia. sulcus ; while the movements of the lips and tongue, and those of the small muscles of the hand, Avhich are the chief accessory movements, are regulated from the operculum. In endeavoring to discriminate ])etween the fundamental and acces- sory portions of the C(mducting paths, the most efficient practical test ss PHYSIOLOGICAL INTRODUCTIOX is to regard all those fibres which are fully medullated at birth as be- lonsing^to the fundamental system ; and those which are non-meduUated at birth, but afterwards acquire this sheath, as belonging to the acces- sory system. In following the course of the pyramidal tract downwards from the cortex, its fibres come together to form one bundle in ihe anterior two- thii-ds'of the posterior segment of the internal capsule. When the internal capsule is examined at birth the pyramidal tract consists of a Fig. 47. Tr.vxsvkrsf. Sectiiin of the Pons on a i.f.vel with the Ahuucens akd Kai'iai. Hoots, ekom a sine months' embryo. (Jlotlified from Kuu. ) The right lialf repi'esents a section made a little lower thau the left P, jiyramidal tract ; ji, accessory jiortiou of the pyramidal tract; JV and TV', transverse fibres of the pons; so, superior olivary body; nlc and^^c, anterior and posterior nuclei of the lateral column respectively, representing the nucleus of the facial nerve; rvii, root of the facial nerve ; vi', nucleus of the sixth nerve ; rvi, root of the sixth nerve ; at, ascending root of the trigeminus. B, The internal division of the peduncle of the cerebellum as it passes from the cerebellum ; L, posterior longitudinal fasciculus ; ar anil ar", the upward continuation of the internal and external divisions of the anterior root-zone of the spinal cord ; I, fasciculus teres. posterior portion (Fig. 47, P) in which all the fibres are medullated, a middle portion (Fig. 45, P') in which medullated and non-medulla ted fibres are mixed, and an anterior portion (Fig. 45, p) in which all the fibres are non-medullated. In the crusta the medullated fibres lie in the outer portion of the middle third (Fig. 4(^ P), the mixed fibres in the inner portion of the middle third (Fig. 4(!, P'), and the non-medul- lated fibres in the inner third (Fig. 4(5, p). In the pons the medullated C E K K 15 K O - S P 1 X A L A N I) C K E E B E L L O - S P 1 X A L SYS T E :^I S . 89 Hbres lie in the anterior and external longitudinal bundles (Fig. 47, P), and the non-niedullated lie in the anterior and internal bundles (Fif, 47, p), while the bundles of mixed fibres lie between these. In the anterior pyramid of the medulla the medullated fibres occupy the pos- terior and external parts of the pyramid (Fig. 28, P), and the non- medullated the anterior and inner side (Fig. 28, j))^ while the area of mixed fibres lies between them. It is probable that the fibres of the medullated area form the conducting paths of the moA'^ements of the muscles of the trunk and of those of the lower extremities, the fibres of the mixe >r present the appearance of a double canal by the growth of adhesions lietween the anterior and posterior walls. In the higher grades of con- genital hydromyelus the spinal cord either disappears entirely, or be- comes split into two halves for a greater or less distance, while the cavity of the central canal communicates freely with the cavity of the -])inal arachnoid: the hydrorrhachis interna is then merged into liydrorrachis externa, as not infrequently happens in spina bifida. (9) Spina bifida consists of an abnormal accumulation of fluid within rhe cavity of the sj)inal arachnoid, associated with a greater oi' less lefonnity of the s])inal canal. c. Gonyenital Malformations of the Skull and Brain. (1) Anencephalia. — The upj)er portion of the skull and Ijrain is entirely absent, and ip occasionally associated with amyelia. (2) Heniicrania. — The anterior portion of the skull is absent, and the brain deficient. (o) Heniicephalia. — The lateral half of the liraiii and skull is de- ficient. (4) Notmccphalus. — The upper part of the skull is deficient, and the vertebral column is not entirely closed in, the brain develoi)ing in the vertebral canal instead of in the skull. 92 MORBID ANATOMY OF THE NERVOUS SYSTEM. (;')) ffydrencephalocele.— The bones of the skull are deficient, an opening being left through which a soft fluctuating tumor projects. The walls of the tumor consist of the soft coverings of the skull and the distended membranes of the brain. The tumor c(mimunicates with the general ventricular cavity of the brain, and can generally l)e emptied on steady pressure. ( id alteration is attended during life with excess of functional activity, it is inferred that the lesion is one of an irritative character; or, in other words, it is inferred that the irritability of the cells and fibres of the part affected is increased. The opposite condition, in wliicli the irritalulity is dimin- ished or abolished, deserves a special name and may be called a de- pressive lesion. (2) I)is<-har(iing and I>estroying Lesions. — Tlie morbid alterations which are attended by paroxysmal and excessive liberations of energy have been called by Dr. Hughlings Jackson discharging lesions. AVi- have seen that the nerve cells are the main generators and accumulatoi-s of energy, hence these lesions always im])licate the gray substance, although it is not always easy to draw a shar]» line of distinction between discharges of eneruv from f^rav substiince and those which result from irritation of nerve fibres. When the affection is accompanied by a distinct destruction of nerve tissue, such as occurs in hemorrhage into the substance of the brain, Dr. Hughlings Jackson has named it a destroying lesion. (1) Dissolution of JVerve Cells and Fibres. a. Morbid Changes of the Ganglion Cells. (1) Hypertrophy. — In acute inflannnation the ganglion cells become swollen, their contents are cloudy and granular, and often pigmented, and their processes also participate in the same changes (Fig. 48, 2). DISSOLUTIOX OF THE XERVOUS SYSTEM. 97 (-2) Shrinking. — In the acute diseases of the f,nay suhstance of the cord the fluid contents of some of the ganglion cells appear to escape, I he cell-wall shrinks around the nucleus and a small quantity of yel- l(.Av pigment, and the cell is contracted into a shrivelled mass, which only presents slight traces of its former structure (Fig. 48, 4). At a Fig 48. Ganglion Cells of the Anterior Gray Horns of the Spixal Cord. (Young.) 1, Healthy caudate cell; 2, Hypertrophied cell; 3, Yellow degeneration (the yellow color cannot be represented here) ; 4, Shrivelled cell ; 5, Chronic atrophy, a group of cells from a case of pseudo-hyper- trophic paralysis, C, Pigmentary atrophy; 7, Vacuolation, from a case of canine chorea (Gowers) ; 8, ( iironic atrophy, I'lum a case of progressive muscular atrophy — "yellow atrophy." subsequent period these cells lose their processes and become converted into small angular masses, in which even a nucleus can scarcely be detected. (3) Multiplication of the Nucleus and Nucleolus. — Tlie nucleus and nucleolus may at times be observed either to have divided into two, or to exhibit an hour-glass contraction indicating that the process of division has commenced. 98 MORBID ANATOMY OF THE NERVOUS SYSTEM. Fig. 49. Alterations in Nerve Fibres after Section. (After Ranvier.) 1 and 2. Two nerve fibres from the peripheral segment of the sciatic nerve of a hare fifty hours after section, examined after maceration for twenty-four hours in a solution of perosmic acid; (n) nucleus of interannular segment, swollen and detached from the sheath of Schwann ; (p) mass of protoplasm, in which fat granules and drops of myeliue {g and my) may be observed. The medullary sheath is com- pletely interrupted at the level of the nucleus, while at a it has undergone strangulation. DISSOLUTION OF THE NERVOUS SYSTEM. 1)9 ;i. Ap|iearance presented by the peripheral fibres four days after section of the sciatic nerve of a hare, originally hardened in a solution of bichromate of ammonia and stained by picrocarmine ; (cy) frag- ments of the axis-cylinder retracted, somewhat tortuous and embedded in a mass of myeline (my) ; tp) protoplasm swollen and granular. 4. Fibre same as 3, but originally colored by picrocarmine after maceration in perosraic acid ; (h) nucleus compressing and partially interrupting the medullary sheath and the axis-cylinder ; p, protoplasm. 5 and 6. Fibres from the peripheric portion of the sciatic nerve of a pigeon three days after section (same method of preparation as 4). 5. Jledian portion of an interannular segment presenting a single swollen nucleus (») surrounded by a mass of protoplasm (p). 6. Presents four nuclei (n" n" n" n") in a single interannular segment. The protoplasm {p) which surrounds them is not segmented, but contains masses of myeline in its interior. 7 Fibres from the central end of the sciatic neive of a hare ninety days after section (same method of preparation as 4). Dark upper portion represents primitive nerve fibre surrounded by the sheath of Schwann (s), and terminating by a knobby enlargement of its medullary sheath (h). From the extremity of this termination a second tube (l') issues, which divides and subdivides until it forms a bundle of verj- fine medullary fibres (F), surrounded by a secondary sheath (s*) emanating from the sheath of Schwann; m, drops of myeline derived from the old nerve fibre. 8. .\ large nerve fibre of the central extremity of the pneumogastric nerve of a hare seventy-two days after section — maceration in perosmic acid. The medullary sheath (t) terminates by a knobby extremity (6), and from this extremity secondary medullated nerve tubes (<'<"; issue, as well as fibres without myeline ; (s) the sheath of Schwann of the primary fibre forming secondary nerve sheath (s') for the nerve fibres which issue from it. 9. A nerve tube of the peripheric segment of the pneumogastric of a hare six days after section. The portions a a, which are neither occupied by drops of myeline nor by nuclei, are collapsed, and the tube is contracted at this level, n n, nuclei of the interannular segment, having undergone proliferation ; m m, drops of myeline. (4) Vacuolation. — Two or tliree large .spherical air-space.s named vacuoles^ may sometimes be observed in ganglion cells which have undergone a granular degeneration (Fig. 48, 7). (")) Colloid Dejjeneration. — The hjpertrophied cells of the early stage of inflammation may subsequently undergo colloid degeneration. Their processes become transparent, glistening, and brittle, while a large portion of them are broken off so that the cells assume a rounded form. The cell-wall has a glassy appearance, and assumes brilliant tints when stained by various aniline dyes. The colloid appearance may be the result of post-mortem changes, and consequently con- siderable cauti(m must be exercised in accepting them as evidence of disease. (6) Pigmentary Dcijcneration. — The best examples of pigmentary degeneration are seen in the chronic diseases of the spinal cord. The cell-wall becomes contracted around a mass of dark granular pigment, the nucleus and nucleolus are indistinct or obliterated, the processes are atrophied, and many of them have disappeared (Fig. 48, 6). (7) Atrophy. — In chronic diseases the cell-wall becomes dense and contracted, the processes are broken oif, and the remnant of the cell is contracted into a small angular mass, without recognizable nucleus or nucleolus, and finally all traces of the cell may be lost (Fig. 48, 5 and 8). (8) Calcareous Degeneration. — This form of degeneration is ob- served on rare occasions. 100 MORBID ANATOMY OF THE XERVOUS SYSTEM. Although tlic iUustnitions of the morbid alterations of ganglion cells have been^taken from disease of the caudate cells of the anterior gray horns of the spinal cord, yet essentially the same changes are met Avith in the ganglion cells of other parts of the nervous system, and notably in thos'e of the cortex of the brain. It is scarcely necessary to point out how these various alterations conform to the law of dissolution. These alterations, taken as a whole, are a passage from the complexity and nudtiformity of the caudate cells with their numerous processes and well-defined connections to the simplicity and uniformity of the round cell without processes or definite connections. b. Morbid Changes of Nerve Fibres. (1) Wallerian Degeneration. — The most notable morbid alterations of nerve fibres are best studied in the peripheral ends of divided nerves. "When the ])eripheral portion of a divided nerve is examined two days after section, the medulla of the divided fibres is found to be coagulated, opaque, granular, and broken up into cylindrical masses (Fig. 49, 1, 2). The imcleus (?() of the interannular segment has l)ec()me increased in size, and contains a large and well-marked nucleolus. The protoplasm which surrounds the nucleus becomes so al)undant and well develo])ed at the level of the nucleus, that it fills the calibre of the nerve tube, and completely interrupts the medullary sheath. The protoplasm at this level, and at other points where it also accumulates, becomes filled with fine fat "Tanules into which the myehne has been converted, and a similar granular debris may be observed outside the sheath of Schwann, and in the substance of the cells of the endoneuriuni. Duririij; the next two or three days the segmentation of the medullary sheath proceeds, and the cylindrical masses become broken up into globular masses (Fig. 49, 5, 6), which, at the end of the first week after section, are converted into drops of variable size, amongst Avhich a progressively increasing nuniljer of fine fat grainiles may be observed. At this period the altered medulla occupies a larger space than in health, so that the fibies appear broader than usual, but their outlines are some- what irregular and wavy. As the morbid processes advance the me- dulla becomes gradually converted into fat granules, which are finally absorbed. The axis-cylinder is said by some observers to persist for a long time after the medullary sheath has disapi)eare(l, l)ut Ranvier asserts that the protoplasm collects at the level of the interannular nucleus to such an extent that it compresses, and finallv intersects the axis-cylinder (Fig. 49, 3, ;? <•?/), which may also at a subsequent period be cut across by the accumulation of protoplasm at other levels. On the fourth day after section the nucleus, which is situated neai- the DISSOLUTION OF THE XERVOUS SYSTEM. 101 middle of an interaniiular segment, contains a large and distinct nucleo- lus (Fig. 41t, ."), n), which may present an hour-glass contraction, or be divided into two. After a time the nucleus exhibits a similar trans- formation, and ends by becoming completely divided into two nuclei, each of which may subsequently undergo subdivision, and these four nuclei may l)e found in one interannular segment (Fig. 49, 6, n" n" n" n"). At a later ])eriod of the degenerative process the greater portion of the medulla is absor1)ed, although some globular masses may accumulate at certain points in the length of the fibre (Fig. 49, 6, in), the process of multiplication of nuclei ceases, and even the axis-cylinder disappears from considerable portions of the length of the fibre. The result of this process is that the sheath of Schwann is completely empty of its contents at certain points, and collapses so that the degenerated fibre appears very slender (Fig. 49, a a). The calibre of the tube is dis- tended at intervals by elongated nuclei arranged in a series (Fig. 49, 9, n n), by fragments of the axis-cylinder, or by globular masses of altered myeline (Fig. 49, 9, »?), and the degenerated nerve tube now appears as a delicate pale band with irregularly undulating contour. With the disappearance of the medullary sheath the degenerated nerve loses its white color and assumes a gray appearance, the fibres shrink, and the nerve looks small and wasted. This process is probably accom- panied Ijy proliferation of the cells of the endtmeurium, or even of the perineurium, and in long-standing cases the newl}" found tissue under- goes cicatricial shrinking, or cirrhosis, rendering the texture of the de- generated nerve denser and adding to its atrophied appearance. (2) Regeneratvni of Nerves. — Under favorable circumstances, the process of dissolution is arrested and a new evolution begins. If the ends of the divided nerve are maintained in apposition during the repa- rative process, it is probable that the axis-cylinders of the central and peripheral ends may become connected before any serious degenerative changes have occurred in the latter of the two segments. But when the ends are not in apposition, the nerve tubes of the peripheral seg- ment become degenerated in their entire extent, and the subsequent regeneration is eifected by an active growth of the nerve tubes of the central segment. Several ways are described by Ranvier in which the central ends give rise to new nerve fibres, but only one or two of the more common of these will be mentioned here. The central tube terminates by a slight enlargement of one of the nodes (Fig. 49, 7), and from this extremity a nerve tube {t') issues, which, although thin, is furnished by a medullary sheath {s') and interannular nucleus. This tube subdivides into two others of almost the same size as itself, and each of these in its turn subdivides into two new nerve tubes, so that the old sheath 102 MOEBID ANATOMY OF THE NEKYOUS SYSTEM. of Scliwann becomes distended by a bundle of new fibres (Fig. 4) Capillar^/ Extravasations.— In the early stage of inflammation of nervous tissues the affected part assumes a reddish color, and lie- comes studded hx a number of capillary extravasations, each about the size of a pin's head, these being sometimes so numerous that the part presents the appearance of a hemorrhagic infarct. {<-) Thirkemn;/ of the walls of the vessels of the nervous system is found in cln-onic Bright's disease similar to that which occurs in the vessels of the body generally in that disease. (d) Perivascular Changes. — The most important perivascular changes observed in disease of the nerve centres are caused by migration of the white corpuscles of the blood into the perivascular lymph spaces and surrounding tissues. The number of leucocytes surrounding a vessel may sometimes be so great as to constitute what has been called a miliary ahsress. (e) Atlieroina and Aneurism. — The vessels of the brain are as sub- ject to atheromatous changes as those of the body generally, and these changes are very prone to occur in syphilitic subjects at a comparatively early age. When the cerebral arteries are diseased the smaller branches often undergo saccular dilatations, which have been named by Charcot )inliary aneurisms. They are said to lesult from a kind of arterial sclerosis of the nature of a chronic periarteritis, consisting of multijdi- cation of the nuclei of the lymph sheaths and adventitia, with atrophy of the muscular coats. These aneurisms ai-e liable to rupture, and thus give rise to massive hemorrhages in the brain. Atheroma of the vessels may also lead to aneurisms of the medium sizeil and larger arteries of the brain, which may compress and desti-oy the nervous substance like other tumors, or cause sudden destruction of large })or- tions of it by rupturing and giving rise to massive hemorrhages. (/) Occlusion of Bloodvessels. — In valvular diseases of the heart a fibrinous mass may be washed off from the left cavities of the heart or their valves, or from the pulmonary veins, or an atheromatous aorta, and may be lodged in one of the arteries of the brain, the left middle cerebral artery being the one most liable to be occluded. This process is termed cmholis)n. The embolus sometimes consists of a cancerous nodule washed from the pulmonary vessels in cancer of the lungs, or of a syphilitic nodule which had projected into the interior of one of the arteries of the neck or brain. A cerebral vessel may be occliuled l)y the locid formation of a clot, a process which consti^ites thrombosis. (4) Morbid Changes of the Blood. In cases of pysemia, morbid products are conveyed in the blood, and metastatic abscesses may form in the brain and other parts of the ner- nSSOLUTION OF THE NERVOUS SYSTEM. 105 vous system, and morbid changes are apt to occur in the nervous tissues in blood diseases like anaemia, leucocythfemia, and the specific fevei's, and in those cases in -which the blood contains a chemical poison like strvchnine, lead, and alcohol. (")) Nem- Formations. (a) Neuromata. — Growths in nerves may be divided into (j ) true and (jj ) false neuromata. ( j ) True neuromata consist of a growth of nerve fibres mixed with a connective-tissue formation. True neuromata have been divided into two varieties according to the character of the nerve fibres found in them. In one form the fibres are medullated, and consequently it has been called by VirchoAv neuroma myelinirum ; whilst in the other form the fibres are non-medullated, and the tumor has been named by the same author neuroma amyeliniewn. True neuromata have also been divided into several varieties according to the amount and character of the connective-tissue basis and to the degree of vascularity, the more usual names applied to them being Jibro-neuroma, glio-ncuroma, myxo- neuroma., and neuroma tcleangiectodes. True neuromata occur most fre([uently in spinal nerves, rarely in sympathetic nerves, and still more rarely in one of the cerebral nerves. They vary from the size of a millet-seed to that of the closed fist. Neuromata consisting of both gray and white matter have occasionally been found in the brains of lunatics, being situated on the surfiice of the ventricles. (jj ) False neuromata consist of tumors of various kinds, but in which there is no formation of nerve fibres, these fibres Ijeing indeed injured or destroyed by compression. The following false neuromata are met with : fibroma., often forming small knots luimed tubercula dolorosa; myxoma, frequently met with in nerves, and sometimes con- taining cysts, when they are called neuroma cysticum ; ylioma, found in the auditory nerve ; sarcoma occurs in nerves, and transitional varieties between it and fibroma and myxoma are not unfrequently observed : carcinoma occurs occasionally as a primary, but much more frequently as a secondary growth ; syphilitic gumma, most frequently found in the cerebral nerves ; and lepra nervorum appears as a difliised, more or less fusiform swelling of the nerves. The size of neuromata is extremely variable, being sometimes not larger than a mustard-seed, and at other times as large as a man's head ; the majority range between the size of a bean and that of a hen's egg. The number of the tumors is as variable as their size. In some cases there is only a solitary tumor, while at other times a large number may 100 MORBID ANATOMY OF THE NERVOUS SYSTEM. be present, either at a circumscribed spot or distributed over the body, the number in some cases being as high as from eight hundred to sevei-al thousands. The nerve sometimes passes on one side of the tumor ; at other times tlie tumor occupies the centre of the nerve ; while in other cases the nerve runs directly into the tumor, the fibres breaking up into a kind of brush or pencil. (h) Gh'oiiiata form tumors which vary in size from a cherry-stone to that of the closed fist ; they may be localized in any part of the brain or spinal cord, but are most frequently found in the hemispheres of the brain. Gliomata consist of a matrix and an abundant admixture of round, oval, or stellate cells with granular contents and one or two nuclei, the structure of the tumor being like that of the neuroglia. When the cells are abundant the tumor is soft, vascular, of a grayish- red color, and infiltrates into the nervous tissues : l)ut when the cells are relatively few, and the matrix, which is fi)rmed of fine fibrillge or a dense reticulum, is abundant, the tumor is Jiard, not very vascular, white in color, and it is more or less cii'cumscribed, although never encapsulated. The hard gliomata are allied in general characters to the fi])romata, and intermediate forms are met with which are termed jibro-jiUoiimta. Transitional forms are also observed between gliomata and sarcomata, named olio-sarcomata. \X other times jjliomatous tumors undergo a mucoid degeneration, and they then reseml)le myxo- mata; Avhile some of them are so richly sui)plied by bloodvessels that they have been named telangiectatic gliomata, these being of great importance from their liability to hemorrhage. (c) Hyjjerplasia of the 'pineal (/land is very similar to gli»mm. It forms a solid, grayish-red, slightly lobulated tumor, which may grow to the size of a walnut, or larger. In old persons the tumor generally contains a large number of sand-like bodies. (d) Myxomata take their origin, like gliomata, from an overgrowth of the neuroglia, but are }-arer in the brain tlian in the spinal cord and periphei'al nerves. {e) Solitary tuhcrde forms a hard, rounded nodule, which varies from the size of a pea to that of a pigeon's egg, and, on section, the interior IS seen to be yellowish and cheesy ; while the outer cortex, which is only about a line in thickness, is of a reddish-gray color, and very vascular. These tumors are met with in all parts of the brain, but then- favorite seat is the cortical substance of the cerebrum and cere- bellum, close upon the cortico-medullary boundary. It is also one of the most fre(|uent forms of tumor met with in the spinal cord. Tliis DISSOLUTION OF THE XERVOUS SYSTEM. 107 ruiiiov is often imilti])le, but Avlieii it is solitary it may attain a consider- able size. (f) CarcinoiUKtd may gioAv on the outer surface of tlie dura mater, and, ultimately perforating the bones of the skull, form fungus lucma- todes of the dura mater. It may also grow from the under surface of the pia mater, and the growth may then be primary or secondary ; but primary cancer in this situation is the more common of the two. Can- cerous tumors of the brain may be single or multiple. They destroy the neighboring tissues by pressure and infiltration, and are usually suri'ounded by a zone of softened tissue, of about a line in breadth, in which active growth proceeds. (//) Cholesteatoma, or })earl cancer, appears to be derived from the l)ia mater, and is usually situated in some hollow at the base of the brain. The tumor, on section, is hard, pearly, non-vascular, and com- posed of epidermic cells, arranged in concentric layers, which have undergone partly horny and partly fatty degeneration. The tumor is enclosed in a delicate fibrous capsule, and its surface presents a beautiful mother-of-])earl lustre. These tumors grow very slowly, and may remain for a long time without giving rise to symptoms. (//) Papilloma of the cere])ral pia mater is occasionally met with. (^) Syp1nlomat(( may reach the size of a walnut or of a hen's egg, and are usually found near the surface of the brain, developing from the perivascular sheaths. They are only met with in the cord on rare occasions. {k) Sarco)nata aj)j)ear as hard, slightly vascidar, round, somewhat nodulated tumors. Every variety of sarcoma is found in the brain, and transitional forms between sarcoma and other tumors are named fflio-sarcoma, myxosarcoma, etc. In some of the spindle-celled sar- comas the cells are arranged in concentric layers or nests, and conse- quently this form has been named "nested sarcoma." (?) Melanoma is a pigmented sarcomatous tumor Avhich springs from the pigment cells of the pia mater. (m) Lipoma has occasionally been met with on the inner surface of the dura mater, and the raphe of the corpus callosum, and the fornix. in) Psammomum is a tumor with a basis of connective tissue, or sometimes of mucoid tissue, which is distinguished by containing calca- reous concretions. It appears to be a calcareous deposit in tumors of widely different structure, the most frequent of these being nested sarcoma. (o) Osteomata are the rarest of all intracranial growths. (p) Cystic growths are caused 1:)y a portion of the posterior cornu of the lateral ventricle l)eing cut off from the general cavity by dropsy 108 MORr.ID ANATOMY OF THE XERVOUS SYSTEM. of the septum lucidum, and cystic degeneration of the pineal gland and pituitary body, and gliomatous tumors. (r) Angiomata generally occur in the l)rain as a complication of other tumors such as glioma. Pachymengitis hc\?morrhagica belongs to this class. (6) Ankurism. Aneurisms of the larger cerebral vessels are not very rare, and when they attain to a considerable size they give rise to the usual symptoms of an intracranial growth. (7) Parasites or thp: Brain. [a) Cysticcrcus cellulosa is met with in the parts of tlie l)rain which are richly supplied with blood, and the parasite is sometimes found in other parts of the body as well as in the brain. Cerebral cysticerci are usually enclosed in a soft capsule, in which the animal may be seen with the naked eye as a small tubercle, and its neck, with the charac- teristic booklets, may be discovered on microscopic examination. (b) Echinococcus hominis form cysts Avhich often attain to a large size in the brain. In a case reported by Dr. Morgan the cyst Aveighed eighteen and a half ounces, and contained eighteen ounces of serum. They reach their greatest size in the hemispheres and the ventricles, especially in children before the foutanelles are closed. The cyst is composed of an external fibrous membrane, which encloses the para- sites ; its internal surfice is lined l)y small l)uds, each about the size of a millet-seed, which are provided with the characteristic ring of booklets. o. Dissolution of thk Nervous System {continued). a. 3fassive HcmorrJiagcs. Massive hemorrhages generally destroy a considerable portion of the nervous system. In the recent condition the apoplectic focus forms a dark red soft clot, which is frequently mixed wdth the debris of the brain substance. The internal surfiice of the cavity is irregular and consists of torn shreds of cerebral tissue, and it is surrounded ])y a zone of variable thickness in which the tissue is softened by the inhibi- tion of serum, and in which numerous punctiform hemorrhages are observed. If the patient survives, the tissues surrounding the blood- clot become softened partly by the imbibition of serum and partly from a retrograde fatty metamorphosis of the torn fragments of brain tissue, and the softened tissues, when mixed up with the blood clot, form a DISSOLUTION OF THE NERVOUS SYSTEM. 109 dark cliocolate-i-olored mass of the consistence of gruel. The hcematin uoAv becomes grachially absorbed, and the substance filling the cavity changes to a brighter red or saffron color. After a time a fibrous cap- sule forms round the clot, and the solid constituent becoming absorbed, a cyst is formed -which contains at first a turbid, and subsequently a clear, limjjid, or straAv-colored fluid, having frequently suspended in it a film of loose spongy connective tissue. When the cyst is small, and the fluid is absorbed, the opposite walls may come in contact and mlhere by a connective tissue, -which usually contains a considerable amount of pigment, and gives rise to the appearance known as the a|)()plectic or hemorrhagic cicatrix. h. Jlorbid Changes caused by Occlusion of Bloodvessels. ^Vhen a terminal artery becomes occluded the arterioles and vessels of the ])art are imperfectly nourished, and consequently their walls dilate and fre<|uently rupture, the former causing redema and the latter hemorrhage. The softened tissues are named red, yellow, or white softening according as a considerable amount, a moderate amount, or no 1)lood is extravasated from the vessels. e. Morbid Clianges caused by Thickening of the Walls of the Arterioles. The walls of the Ijloodvessels of the nerve centres become thickened in Brights disease, and the nervous tissues surrounding the altered vessels undergo, in some cases, morbid changes more or less similar to those of chronic inflammation, and consisting of an increase of connec- tive tissue and destruction of nerve cells. This condition may be named vascular sclerosis. d. Inflammation of the Nervous System. (1) Acute inflammation of nervous tissues is characterized in its first stage by congestion, capillary extravasations, and some oedema of the tissues. If the ju'ocess proceeds further, it causes softening of the inflamed part. Inflammatory softening may be divided into (a) red, {b) yellow, (c) white, {d) gray, and ie) green or purulent softening. [a) Red Softening. — The spot affected with red softening is soft, and swells up aljove the level of the surrounding surface on section. The aflected tissue may be washed away by a gentle stream of water, or it may be diflHuent. Numerous capillary hemorrhages may be ob- served, and the aflected part assumes a tint which varies from rosy to deep red, reddish-broAvn, or chocolate. 11(1 M(.KIUI) ANATOMY OF THE XEKVOUS SYSTEM. (//) Yellow Softenhu/.—A^ tlie disease progresses the affected parts l.t'coiiie i)aler and softer, and the color changes to veHow. partly from diffusion and alteration of the coloring matter of the Idood, and partly from degeneration of the medullary sheath. {<■) White Softniinij. — Owing to the continued process of fatty de- generation the color hecomes progressively whiter, and the diseased portions assume a creamy oi- milky appearance, and on section the medulla swells up ahove the surface of the surrounding tissues. {d) Gray Softening. — In consequence of the absorption of fat gran- ules and nerve substance, the affected part gradually assumes a grayish eolor, and finally becomes smaller and more depressed than normal. {e) Green Softenim/. — The white blood-corpuscles may migrate in such large numbers that the affected ])art is converted into a cavity containing a greenish purulent fluid, and constituting an abscess. Microscopical Cha)u/es. — In the early stage of inflammation the arterioles and capillaries are dilated and distended with blood, while they may be enveloped in layers of migrated white and red blood- corpuscles. As the disease advances the walls of the vessels become tliiekened and studded with fat granules and granule cells, Avhile the lymph sheaths are tilled with granular or cellular exudation. The reti- culum of the neuroglia is swollen and thickened, and filled with nuclei, lymphoid cells, and granule cells, while Deiters cells are increased in number. The nerve fibres present irregular contractions and enlarge- ments, the medullarv sheath becomes broken down into globules and is finallv absorbed, and the axis-cvlinders are greatly swollen, while in the second stage the medullarv sheaths are in a state of fattv degenera- tion, and the axis-cylinders are altered or destroyed. The ganglion cells are first swollen, the nucleus and nucleolus may l)e observed in process of division, while at other times they undergo vacuolation, the cell processes are swollen, cloudy, irregular in shape, and partly de- stroyed, and at a later period the cells lose their processes, and shrivel so as to become- reduced to small angular masses without structure. When a cicatrix has formed, the affected spot is occupied by a dense connective tissue containing many nuclei and neuroglia cells, and numer- ous Deiter's cells. When cijsts are formed they are surrounded by a more or less dense layer of connective tissue, and are generally trav- ersed by a loose connective-tissue network. The morbid appearances just described apply more particularly to those occurring in the spinal cord and termed' ctcute myelitis, and in the brain and named acute encephalitis, l)ut essentially the same changes are met with in acute inflammation of nerves. When the inflammation begins in the nerve fibres the process is named neuritis, DISSOLUTIOX OF THE NERVOUS SYSTEM. lU and when in the slieath of the nerve it is named perineuritis. In acute neuritis or periaeuritis the vessels become enhu-ged and distended, and the nerve-trunk is swollen from serous, gelatinous, or fibrinous exudation. If the inflammation subside at ari early date the effusion is absorbed l)efore there is any destruction of the nerve fil)res, and the healthy condition is reestablished. If the inflammatory action is very acute and severe, both white and red corpuscles escape from the vessels, the color of the nerve l)ec()mes yellow or brownish-red, its tissues are infil- trated with sanguineous pus, abscesses may form around its trunk, and the entire structure may l)ecome completely disintegrated. (2) Chronic inpmimation causes the aifected part, as a rule, to be atrophied, and unusually dense or in a state of sclerosis. When the white substance is the subject of chronic inflammation it assumes a gray color, and consequently the condition is sometimes called (p'iiy degene- ration. When the inflammation spreads over a considerable area of tissue it is named diffused sclerosis ; when it is limited to the embrvo- logical tracts of the cord it is named an ascending or a descending sclerosis, according as the process extends from below upwards oi- from above downwards ; when it is limited to certain spots or foci it is named circumscribed or insular sclerosis ; and when these spots are numerous and distributed in diff"erent parts of the nervous system, it is named multiple or dissoninated sclerosis. The terms insular, multiple, and disseminated are applied indiff'erently to the same disease, because, when the sclerosis is limited to circumscribed spots, the spots are also mul- tiple and widely distributed over the nervous system. When the sclerosis is more or less restricted to the embryological tracts the morbid process is supposed to begin in the nervous elements themselves, and consequently some anatomists have called this form of chronic inflammation parencliymatous sclerosis. This distinction is admissible theoretically, l)ut it is not always easy to maintain it practically. A microscopical examination of a part in a state of sclerosis shows that the connective-tissue septa are thickened, and that the cells of the neu- roglia are swollen and their nuclei multiplied. Deiters cells are also increased in size and number, and in long-standing cases the neuroglia becomes converted into a dense fibrillated connective tissue in which a large number of nuclei are observed. The nerve fibres undergo changes more or less similar to those which occur in secondary degeneration of the fibres of the peripheral nerves. The medullary sheath undergoes granular and fatty degeneration, and is finally absorbed ; but the axis- cylinder persists a long time, although it becomes swollen at certain points, and, on being viewed longitudinally, presents spindle-shaped enlargements. After a time the axis-cvlinders also Avaste and disappeai\ [[•1 MOHHID AXATOMY OF THE NEEVOUS SYSTEM. and nothing- remains l»ut a dciise fil)i'illate(l connective ti^^ue. The ualls of the small arteries and veins become thickened, and their calibre is diminished in size. The lymph spaces are destroyed, or contain fat and jiigment granules, while granule cells and corpora amylacea are found scattered through the diseased tissue. The morbid apjiearances just described are met with in the nervous centres, but essentially similar alterations occur in nerves. In chronic neuritis and perineuritis the trunk of the nerve becomes irregularly vascular, and is enlai-ged in some places and atrophied in others. The sheath of the nerve is thickened, fibrous, and resisting, while it is fre- (|uentlv adherent to the adjacent tissues. In cases of perineuritis the nerve filtres are compressed by the exudation and disappear after a time, so that tlie sti'ucture of the nerve is supplanted by a band of connective tissue. Segmental periaxillary neuritis, induced l)y Gombault in the perij)h- eral nerves of guinea-pigs, is a parenchymatous neuritis in which only a part of the nerve fibre is implicated. A segment lying between two of the nodes of Ranvier is diseased, while those on each side of it may remain healthy. Several seginents may, however, be affected in the course of one fibre. The medullary sheath and the protoplasm of the fibre are at fii-st alone implicated in the morbid change, while the axis- cylinder remains for a long time uninterrupted. After a time the diseased segment may either be restored by the growth of a new medul- lary sheath, or the axis-cylinder becomes ruptured, and the ])eripheral end of the nerve then undergoes the Wallerian degeneration. e. Degenerations of the Nervous System. (1) Primary Degeneration. Tlie gray substance of the nervous system may apparently undergo a primary chronic degeneration in addition to the degeneration which is consecutive to inflammation. In the primary degeneration the nerve cells undergo atrophy and various forms of ])igmentarv defeneration. This form of degeneration occurs most probably in the gray substance of the anterior horns of the spinal cord in progressive muscular atrophy, and in the cortex of the brain in the chronic forms of insanity. It is possiVde that the white substance may also undergo a primary chronic degeneration, and the disease known as progressive multiple neuritis appears to be a primary degeneration of the peripheral nerves. The morbid changes which have been found in the nerves in this disease consist of partial or complete destruction of many of the nerve fibres. The perineurium of the individual bundles has also been found thick- DISSOLUTION OF THE NERVOUS SYSTEM. 118 ened, and Levden has observed an accumulation of fat cells between the bundles, and a deposit of pigment around the bloodvessels. Lev- den regards this pigment as a hemorrhagic inflammation of the tissues between the nerve fibres, and he believes that the absence of any sio-n of multiplication of nuclei proves that the nerve fibres had become atrophied through the compression caused by the congestion of the tissues surrounding them. (2) Secondary Degenerations. The Wallerian degeneration of peripheral nerves has already been described, but we have now to point out that essentially the same pro- cess occurs in the conducting paths of the nerve centres. It has already been stated that Waller observed that when a mixed nerve is divided the peripheral portion degenerates throughout its whole course in a few weeks, Avhile the portion attached to the cord does not degen- erate. This statement, however, is only a portion of the truth. He also found that while the efferent fibres degenerate their whole length on division of the anterior root, that the peripheral portion of the afferent fibres do not degenerate on division of the posterior roots. On division of the posterior roots what takes place is that the peripheral portions which are attached to the spinal ganglion remain healthy, but the small central portion which is attached to the cord soon wastes. From these facts Waller concluded that the efferent fibres receive their nutritive influence from the caudate cells of the anterior horns, and the afferent fibi'os from the ganglia of the |)OSterior roots, and he then formulated the general law that nen'e fibres ilegenerate when they are se])arated fi'om their trophic centres. The central conducting paths also undergo degeneration in one direc- tion after division or injury of them, and it may be confidently asserted that the degeneration occurs along the line of conduction of the fibres, some paths undergoing an ascendinf/ and others a di'scending degeneration. (a) ASCENDING DEGENERATIONS. The trophic centres of the columns of (roll and of the direct cere- bellar tracts are situated at their inferior extremities, the ganglia of the })osterior roots or the gray substance of the posterior horns forming the trophic centres of the former, and the cells of the vesicular colunms of Clarke probably those of the latter. The lower limit of the de- generation of these columns will depend upon the position of the lesion of the cord which interrupts the continuity of the fibres, and the deoeneration of the columns of Goll may extentl from the lumbar 8 114 MORHII) ANATOMY OF THE XERVOUS SYSTEM, region of the cord up to tlie termination of the fibres in the cuneate nucleus, while the degeneration of the direct cerebellar tracts may extenil from the inferior part of the dorsal region up to the external surface of the restiform bodies. In both of these degenerations the dis- eased area increases progressively in size from below upwards (Figs. 50, 51, 5:2). A case is reported by Dr. Gowers in which the lower Fig. 50. Fig. 51. TnANSVERsE Sections op the Spinal Cord, fro-ai the middle of the Cervical Enlargement, MIDDLE OF THE DoRSAL RF-GION, AND MIDDLE OF THE LUMBAB EEGION, RESPECTIVELY, SHOWING ASCEND- ING Degeneration of the Cdlvmns of Goi.L(g), and op the direct Cerebellar Tract (dc). extremity of the spinal cord was crushed by a fracture of the spine, and in which, in addition to the ascending degeneration of the columns of Goll, a small area of degeneration w^as observed in each anterior root-zone in front of the lateral pyramidal tract, the latter being healthy on each side. Dr. Gowers suggests that these areas constitute a part of the sensory conducting paths. In lesions of the cauda equina, and sometimes after severe traumatic injuries of the sciatic nerve, the posterior root-zones as well as the columns of Goll undergo ascending degeneration in the lumbar and greater portion of the dorsal regions, but the degeneration becomes limited to the columns of Goll in the upper dorsal and cervical regions. In transverse lesions of the cord the posterior root-zones may also be found degenerated for a short distance above the lesion, but the evidence of degeneration soon ceases, probably because the fibres of these columns soon tei-minate in gray matter. {()) DESCENDING DEGENERATION. (j) Sclerosis of the Pyramidal Tract. Lesions of the cortex of the brain, provided the whole thickness of the gray substance is implicated, are followed by descending degenera- tion of the fibres of the pyramidal tract Avhich may be followed tiirough the internal capsule, crusta, longitudinal fibres of the pons, anterior pyramids of the medulla oblongata on the anterior column of the same side as the lesion, and in the lateral columns of the cord on the side opposite the lesion. A descending degeneration of this kind has also been found in animals after extirpation of portions of the motor area of the cortex of the brain. DISSOLUTIOX OF THE NERVOUS SYSTEM. 115 A focal lesion limited to the middle third of the internal capsule (F\lem of morbid physiology is to interpret morbid functions by morbid .structures, and the hiw ^vhich underlies all our conclusions is that every disordered function is the correlative of a diseased struc- ture : and, invensely, that every diseased structure has for its counter- pnrt a derangement of function. It may be laid down as a general law that, when the irritability of a nervous structure is increased, it will manifest increased functional activity. It may be supposed that a free arterial sui)ply to a part, or a flushed condition of the arterioles, is the necessary correlative of increased irritability ; and, conversely, that a diminished arterial supply, with an empty and contracted condition of the arterioles, is the necessary correlative of diminished irritability. This statement, however, can only be accepted as true within certain limits and with numerous (piali- fications. When the brain, for instance, is very freely supplied with blood so that its substance becomes congested, the irritability of the tis- sues is no doubt at first increased. It must, however, be remembered that the cranium is unyielding, and its contents practically incompressi- ble, so that no additional (juantity of blood can enter into the intra- cranial vessels except Ijy displacing a corresponding (piantity of some other fluid. When, therefore, the vessels become dilated beyond certain nari-ow limits the nervous tissue becomes compressed, the material e.x- changes within the cranium become less than when the circulation passes in normal (juantity and under normal pressure, and the functional activity of the organ is diminished or abolished. A similar process no doubt occurs in the spinal cord and nerve trunks. Congestion in them, when carried beyond certain limits, is also attended with diminution of function, due, no doubt, to compression of the nerve tissues by the dilated vessels. The irritative lesion is attended with increased nutri- tive activity, and C()nse(iuently with free arterial supply ; but this lesion is exceedingly apt to terminate in the opposite condition of diminished nutrition and functional activity. The first stage of inflammation, for instance, is an irritative lesion, and it is attended by excess of func- tional activity, manifesting itself by symptoms of hyperesthesia and hyperkinesis ; Init when the nervous tissues become partly compressed by effiised pi-oducts and partly disorganized by internal changes, the lesion becomes depressive, and the symptoms of excess give place to those of diminution of function; in other words, the symptoms of hyperaesthesia and hyperkinesis give place to those of anesthesia and akinesis. GENERAL MORBID AXATOMY AXD PHYSIOLOGY. 123 But if excess of nutrient activity is not always accompanied bv increased functional activity, neither is diminished nutrient activity always accompanied by diminution of functional activity, When the nutrition of a nerve fibre is gradually lessened its irritability becomes, indeed, increased instead of diminished. The stock of irritable matter which the nerve fibre possesses is no doubt less under these circum- stances, but an increased readiness to discharge the energv is mani- fested : and it is notorious that feeble and angemic persons manifest an undue readiness to respond to the action of stimuli of all kinds, a condition which is correctly designated nervous irritahUity. One other important consideration must be taken into account before the amount of nourishment supplied to an organ or a tissue can be accepted as in any way a measure of the functional activity of the latter. When a strong faradic current is sent through the sciatic nerve of a frog, the gastrocnemius muscle contracts strongly ; but a subsequent current ])assed through the nerve is followed by no reaction until the irritability of the nerve is restored by the absorption of more nourishment. A similar process doubtless occurs in disease of the nervous system. \yhen a part is supplied with an excessive amount of nourishment, the tissues become so irritable that they discharge readily, either sponta- neously, or in response to stimuli which would not affect them under normal conditions. Under these circumstances, excessive discharges of nervous energy readily take place, and these are followed by temporary loss of irritability, and the tissue becomes incapable for a time of per- forming its normal functions. The excessive liberations of energy from the cortex of the brain, which occasion epileptic attacks, for instance, are accompanied by loss of consciousness, which lasts for a considerable time, and the convulsive phenomena are not unfrequently followed by temporary motor paralysis. When the energy of the dischargbui lesion is once liberated, the part affected becomes incapable of performing its functions, until its irritability is restored by the absorption of a fresh stock of irritable matter. The primary effect of almost all chemical agents on the nervous system is to stimulate it, and to increase its functional activity, Avhile their secondary effect is to depress or abolish its functional activity. The stimulant action of alcohol on the brain, for instance, is followed by a stage of depression, which may amount to complete abolition of the cerebral functions or coma. Strychnine increases the irritability of the gray substance of the spinal cord ; but the reflex actions, which are at first greatly exag- gerated, become ultimately abolished, and the animal poisoned by strychnine often dies from paralysis. Curara, which may be taken as the type of nervous sedatives, paralyzes the terminations of the motor 124 GENERAL MORBID ANATOMY AND PHYSIOLOPxY. nerves, yet Bernard i)rove(l that it first increases the irritability of the fibres. Tlie direct tendency of all destroying lesions is to abolish function. It 111 list, however, be remembered that these lesions are frequently sur- rounded by a zone of nervous tissue Avhich is in a state of irritation, and the prominent symptoms of the affection are often produced by tliis zone, consequently the symptoms may be indicative of excess of func- tional activity. A gummatous tumor, for instance, in the cortex of the brain is generally declared by epileptoid convulsions ; yet the direct tendency of the tumor, in so far as it has destroyed and replaced ner- vous tissue, is to abolish function. In such cases, both the direct and indirect effects of the tumor are often manifested : the former by para- lytic and the latter by convulsive symptoms. Even the ischa?mic soften- ing, caused by plugging of vessels, is often surrounded by a congestive zone of tissue, and the latter may give rise to symptoms of irritation. CHAPTER lY. GENERAL SYMPTOMATOLOGY. Disease of the nervous system gives rise to disorders (A) in the feelings of the patient — the a'sthesio7ieuroses, (B) in the nutrition of the various tissues of the body — the trojjJwneuroses, and (0) in the movements of the body as a Avhole and of its various parts — the kinesioneui'oses. A. THE .ESTHESIONEUllOSES. The assthesioneuroses may be divided into disorders (i) of the primary or elementary feelings — the prima)'!/ ajsthesioneuroses, and (ii) of the secondare/ or compound feelings — the secondary nesthesioneuroses, while each of these divisions may be subdivided into (1) disorders of the common subjective or emotional feelings (pleasures and pains), and (2) the s})ecial. objective, or intellectual sensations. 1. TjIE PkI.M.VUY .ESTIIESIOXEUROSES. The general disorders of the feelings consist, first, of excess of the normal sensation caused by a stimulus, which is named hypera'sthesia when the objective feelings are increased in acuteness, and hypcrahiesia when the common sensation of pain is increased ; secondly, of diminu- tion of the normal sensation evoked by a stimulus, which is named awcsthesia when the objective feelings are diminished, and analgesia when the subjective feelings are diminished in acuteness : tJiirdly, of l)aroxysms of pain in the region of distribution of a sensory nerve in the absence of external stimulus or active inflammation of the nerve, named neurcdgia ; fourtldy, of abnormal sensations, such as )iunil)ness, tickling, crawling, itching, and feelings of heat and cold, also felt in the absence of external stimulus, and grouj^ed togetlier under the name of parcesthesiCB ; and fifthly, a diminution or increase of the interval wliich elapses between the instant at which a stimulus is applied to a sensory surface and the moment at wliich the suliject makes a voluntary effort to indicate that the sensation has l)een perceived, named accelera- tion or retardation of sensory perception respectively. Disorders of the primary or elementary feelings may be divided y2i] GENERAL SYMPTOMATOLOGY. ■iccordin- to the tissues and organs implicated into sensory afiections : 1 of the" skin and exposed parts of the mucous meml.ranes : 2. the voluntary muscles; 3, the bones and joints; 4, the viscera; 5, the special senses. The anatomical division is traversed at right angles by a physiological division into sensory disorders of (1). the common or subjective feelings, and (2) the special or objective feelings. 1. Cutaneous ^Esthesioneuroses. Sensory disorders are known through the statements and gestures of the patient, and the information obtained by this means must be checked by a systematic examination. The foilowino- tests of the various forms of cutaneous sensory dis- orders may be used at the bedside : [a) Common cutaneous sensations may be tested by the i»rick of a pin, application of heat and cold, i)inching, and firm pressure, or the application of the faradic current. (7;) The rapidity of sensory conduction may be tested by getting the patient, with closed eyes, to give a signal by voice or by a tap on a table immediately on feeling the prick of a pin, and noting the interval which elapses between the prick and the signal. (c) The sense of pressure may be tested by Weber's method, which consists of the superimposition of weights to determine the smallest difference which can be perceived. To exclude the muscular sense the part to be tested should be at rest on a table, and the sensation of tem- perature may be excluded by the interposition of a bad conductor like a wooden disk. (d) The sense of locality may be tested by touching some part of the surface with the finger or point of a needle whilst the j)atient"s eyes are closed, and asking him to indicate the point touched. A better plan is to ascertain to what distance the points of a compass must be separated from one another before they are felt as two. The distance to which the points of the compass must be separated varies for differ- ent regions of the body, so that the observer must know the normal scale of difference before drawing any conclusions from the results obtained, but in many cases valuable information may be obtained by comparing the anaesthetic area with the corresponding part on the opposite side, which may be normal. {e) The sense of temperature is tested by applying hot and cold bodies to the surface when the patient's eyes are closed, and asking him to indicate each time whether the temperature of the touching body was hot or cold. Two test-tubes, one filled with cold aii.l the THE PEIMARY .ESTHESIOXEUROSES. 127 Other with hot water, aiiSAver the purpose of testing very well, or two silver spoons, one clipped in hot and the other in cold water, are e([ually efficient and often more convenient. (/) 'i'lie sense of touch is a compound sensation, but it may be roughly tested by means of a light touch with a featlier, and asking the patient to indicate with closed eyes each time he is touched. a. Cutaneous Hyper.esthesi.e. (1) Hyperpselaphesia, or abnormal acuteness of tactile sensibility, declares itself by excessive reaction to the various tests for the senses of pressure and locality. A smaller difference than usual in the in- crease of pressure is perceptible, and the diameters of the areas of sensibility are unusually small. (2) Foli/ccsthesia is the condition in which one point of the compass on being placed on the skin is felt as two, three, or five points. (3) AllocJdria is a condition in Avliich the patient is not sure, and is often in error when the eyes are closed, as to w^hich side of the bodv is touched, even though the cutaneous sensibility is more or less normal in other respects. (4) Girdle seiisations consist of a subjective perception Avhich pro- duces the impression of having a girdle or a broad bandage tied about the trunk or limbs. (o) TJierj7io-Jti/pe)restJiesia consists of an alniormal acuteness of the sense of temperature, so that differences in temperature so slight as to be inappreciable in health are recognized. (0) Causalgid is a name given by Dr. S. Weir Mitchell to a distress- ing pain which appears to belong to the thermo-hypersesthesiee. It is described by patients as an intensely burning sensation, and is compared to that caused by a mustard plaster, or by '' a red-hot file rasping the skin.'" It is generally associated with " glossy skin,"' but often pre- cedes the trophic changes of the skin. (7) Dy^cesthnia is a term introduced by Charcot to indicate a sensa- tion of a peculiarly distressing and vibratory character, which ascends towards the central end of a limb and descends towards its extremity. The sensation is excited by the slightest touch or the application of a cold body to the surface, and it persists from several minutes to a quarter of an hour after the exciting cause has ceased to act. After a short time an analogous sensation may be felt at a corresponding point of the limb, opposite to the one primarily excited. (8) Hyperce-'sthetie spots consist of circumscribed patches of skin which are exquisitely painful to touch, and which are subject to attacks of spontaneous pains of a burning character. l-)s genp:ral symptomatology. (!)) Cutaneous hyperalgesia consists of an increased sensibility of the common sensations, and is much more frequent tlian increase of tactile sensibility. In this condition, stimuli, Avhich in health give rise to touch, or even to pleasant sensations like the minor degrees of tick- liiiii-. noAV become i)ainful. Thermo-hjperahjesia may be applied to desiijnate the condition in which contact Avith a hot or cold body gives risernot to a feeling of temperature, but to a i)ainful sensation. I). Cutaneous An^esthesi.e. (1) Distribution of Ancesthesia. — Anaesthesia or sensory paralysis is sometimes distributed in limited patches or in the area of distribution of particular nerves, and it is then termed cirrumscriht'd anaesthesia. At other times it appears in the form of a zone of variable Avidth sur- rounding the bodv on one or both sides, and it is then named anaesthesia in the form of a girdle. When it is distributed over the lower half of the body and the lower extremities it is tei'med parana'sthesia ; and when over the lateral half of the body, including half tlie face and the extremities, it is named heiiiiana'sthesia. (2) Total anaesthemi is a diminution or loss of every form of cuta- neous sensibility, and partial anaesthesia a diminution or loss of certain forms of sensibility while others are preserved. (8) Api^elapliesia or tactile ancesthesia denotes a diminution or h)ss of the acuteness of tactile sensibility, a condition which is fre([uently associated with hyperalgesia. Severe pain is sometimes felt in anes- thetic parts, and the condition is then called anaesthesia dolorosa. (4) Thermo-ana'Sthesia means insensibility to heat or cold, a condi- tion which sometimes occurs as an isolated affection. (")) Analgesia diQiioie^ a diminution or loss of the sensation of i»ain. Analgesia, with preservation of the tactile sensibility, is the most fre- (pient form of partial sensory paralysis. (6) Retardation vf sensory conduction may be employed as a test of any form of auBesthesia, and gives rise in the partial varieties to the following anomalous phenomena : (a) Separation of Tactile and Painful Impressions. — In locomotor ataxia the prick of a needle causes a prompt feeling of touch, which is often followed in two or three seconds by a feeling of pain. In cases of thermo-ansesthesia, a test-tube holding hot water may at first give rise to an immediate feeling of touch, to be followed in two or three seconds by a sensation of temi»erature. (h) Double Painful Sensations.— In some cases of locomotor ataxia, pricking the skin on the back of the foot with a needle is sometimes THE PRIMARY .ESTHESIONEUROSES . 129 followed bv a first painful sensation, and, when this subsides, bv a sec(»nd painful sensation, which is usually of greater intensity and more prolonged than the first. The first is felt after a lapse of two and a half to three seconds subsequent to the prick, but the second is not felt until after another interval of from two to five seconds. {(■) Persistent After-sensations. — In some cases of partial ansesthesia, pinching the skin or pricking with a needle gives rise to a sensation which begins slowly, but gradually increases in intensity, and is much more severe than the i)ain which occurs in health. {d) Inability to Count Successive Impressions. — Closely connected with these persistent afiter-sensations is the inability of the patient to count correctly several imi)res.sions made in quick succession. Enume- ration of successive impressions presupposes an interval to elapse between the sensation caused by each ; but, when the conduction is retarded, each sensation is unusually prolonged so that the first does not fade before the second begins, and so counting Ijecomes impossible. c. Cutaneous Par.esthesi.e and Paralgesia. (1) Pruritus is a sensation caused l)y aluiormal irritation of the nerve-ends of the papillae of the skin, or by a state of undue irrita- bility of these nerve terminations themselves. Pruritus is related to such sensations as tickling and to burning and stinging pains, but an irresistible tendency to scratch is its characteristic symptom. ('2) Formication does not amount to pain, but is described as a feel- ing of creeping or pricking, or is compared to the crawling of ants. Formication occurs as a transitory symptom in minor mechanical in- juries of nerve-trunks, and is felt in the foot as a sensation of " pins and needles," numbness, or ''sleepy sensation," Avhen the sciatic nerve is compressed for some time. d. Neuralgia and Neuralgiform Pains. (1) Neuralgia consists of periodic attacks of severe pain, occurring suddenly and spontaneously in the course of one of the larger nerve- trunks, and ramifying in a few or all of its sensory branches. The character of the pain in cutaneous neuralgia will be described when the special forms of it are under consideration, but we shall here refer to some of the more prominent phenomena of the affection. During the height of the neuralgic paroxysm there is an irradiation of the jMin to other sensory nerves, generally to branches of the same trunk or to neighboring nerves, but occasionally to more or less distant nerves, and the neuralgic pain is accompanied by various parsesthesiae, hyperaesthesia, or sometimes anaesthesia. 130 GENERAL SYMPTOMATOLOGY. Painful Points.— These points were first described by Yalleix under the name of jyoints douloureux. An examination of the part during an attack of superficial neuralgia will reveal one or more points which are extremely sensitive to the pressure of the tip of the finger. The sensitiveness of these points stands almost in a direct relation with the severity of the paroxysms, but they may be present occasionally during the period of remission, and in some cases pressure upon them induces an attack. These tender spots are found at various points in the course of the affected nerves, when their trunks pass from a deeper to a more superficial level, and especially where they emerge from bony canals or pierce fibrous fascia?, or even where a nerve lies on a hard bed so that it may be easily compressed. Point Apophymire. — Trousseau believed that in all forms of neural- gia the spinous processes of the vertebrae corresponding to the origin of the painful nerve, and which he calls points apophysaire or spinous points, are painful on pressure, but these points are also present in spinal irritation and in myalgia. The concomitant symptoms of neuralgia will be described along with the special forms of neuralgia. (2) Lightning-like Pains. — In locomotor ataxia patients often suffer from spontaneously occurring paroxysms of distressing pains, which are compared by them to forked lightning darting through the body, and have been described under the name of general neuralgia, or neuralgic rheumatism. 2. Sensory Affections of the Voluntary Muscles {^Muscular ^-Esthesioneuroses) . a. Muscular Hyper^esthesia and Hypkralgesia. The feeling of unrest and desire for constant change of position, called the ''fidgets,"' appears to be due to muscular hypene^thesla. In spasmodic wry-neck, and in "cramps" the hyperiesthetic condition is often very great, and causes intense pain. The excessive feeling of fatigue and prostration which occurs on slight exertion in the prodromal stage of acute diseases, is probably due to an increasing muscular sen- sibility, and consequently this condition may be regarded as a muscular hyperalgesia. Painful conditions of the muscles are called myalgia or myodynia. Pain is most frequently met with in the muscles of the neck and of the lumbar region, and inasmuch as it corresponds to cutaneous neuralgia and arthralgia, it may be called muscular neuralgia or myoneuralgia. THE PRIMARY .ESTHESIONEUROSES. 131 h. Muscular Ax^sthesia. Muscular aniiestliesia consists of diminution or loss of the common sensibility and of the sense of muscular effort. When muscular sensi- bility is lost, as tested by the faradic current, while the muscular sense is retained, the condition is termed muscular analgia, or muscular analf/rsi((. When there is a diminution or loss of the capacity of rec- ognizing small weights, or of perceiving small differences by means of muscular effort with closed eyes, the condition is called ancesthesia of the muscular sense. (1) Tests of Muscular Sensibility. — The state of muscular sensi- bility is best tested by the faradic current. When a healthy muscle is made to act, a dull feeling accompanies the contraction, this feelino- being much increased in muscular hyperalgesia and diminished or lost in muscular analgesia. (2) Tests for Muscular Sense. — To test the muscular sense the patient should be made to lift various weights, and to form an estimate, with closed eyes, of the weights and of the differences of successive Aveights. In order to eliminate the cutaneous sense of pressure, the weights should be placed in a cloth and suspended from the limb to be tested. The patient may also be made to move the limb into certain prescribed positions, with closed eyes ; he may be asked to touch a particular part of the body, such as the tip of the nose, with the index finger, to take hold of a ticking watch held before him, or to describe an imaginary circle on the floor with the big toe. The patient fails to accomplish these actions with precision when there is muscular ancesthesia. 8. Sensory Affections of the Joints and Bones {Articular and Osseous jEsthesioneuroses). a. Osteoneuralgia. The bones are sometimes the seat of severe pain, and when the pain is not caused by recognizable anatomical changes the condition is re- garded as a neuralgia, and named osteoneuralgia. Neuralgia of the bones differs from cutaneous neuralgia in not radiat- ing along the course of the principal Ijranches of the affected nerves. It is probable that the sensory nerves of the Ijones reach them along with the sympathetic plexus which surrounds the vessels. 2^32 GENERAL SYMPTOMATOLOGY. 6. Arthroneuralgia. Arthroneuralgia consists of severe neuralgiform pains in a joint in the absence of any recognizable anatomical alteration of it. The pain occurs in paroxysms which come on spontaneously, and which are sep- arated by intervals of complete or comparative freedom from pain. The pain is sometimes described as tearing, or shooting through the joint like lightning, and at other times as a boring or stabbing pain. The patient may also complain of numbness and formication about the joint, or of sensations of heat and cold, and the skin over the joint is often hyperjesthetic in the early stages of the affection, and anaes- thetic when it is of long standing. The pain is much increased when tlie patient's attention is directed to it, while it is diminished under the influence of general fatigue, and does not prevent the patient from sleeping. Pressure increases the pain, but, as occurs in cutaneous neuralgia, slight and superficial pressure may produce intense pain, while deep, continuous, and uniform compression produces no effect, or even relieves the pain. Painful points may be obtained on pressure, but their position is somewhat indefinite. Neighboring nerve-trunks may also be found painful on pressure, and the spines of some of the vertebra may likewise be tender to pressure. In some cases spastic contraction of the muscles surrounding the joint occurs, while in other cases the limb is feeble and lie]i)less, owing, perhaps, to the fear of inducing a paroxysm of pain by movement at the joint rather than to any muscular paralysis. The vaso-motor disturbances consist of redness, heat, and increased secretion of sweat in the neighborhood of the affected joint, and a cir- cumscribed dough or fluctuating swelling is sometimes observed in the skin over the joint, which was compared by Brodie to an unusually large urticaria wheal. Swelling of the joint from serous effusion within the capsule may occasionally take place, and is apt to be regarded as of inflammatory origin, and when effusion takes place in the tissues sur- rounding the joint as the result of irritating applications, the diagnosis is still further obscured. 4. Sensory Affections of the Internal Organs ( Visceral ^sthesionniroses). The visceral sensations belong to the common or subjective sensa- tions, and consequently excess of a normal visceral feeling may be regarded as a hyperalgesia, while an altogetlier abnormal visceral feel- ing belongs to the parmsthesim ; but it is by no means easy to draw a distinction between these two kinds. Diminution or loss of the visceral THE PRIMARY .ESTHESIOXEUROSES . 133 feelings constitutes a visceral ancesthcsia, or, more correctly, a visceral a. Visceral Hyperalgesi.e and Paralgesia. (1) Titillation is a sensation induced by irritation of the sensory brandies of the vagus, especially the superior laryngeal branch, or by undue irritability of the ends of the nerve, and corresponds with pru- ritus of the external skin ; and as pruritus leads to an irresistible ten- dency to scratching, so titillation leads to the reflex respiratory move- ments Avhich produce coughing. (2) G-Iobus is a sensation which gives the feeling of a ball ascending from the epigastric region to the throat. It is a frequent symptom of hysteria, and occasionally forms the aura of an epileptic attack. Globus is supposed by some to be caused by spasm of the oesophagus and pharynx, and it has consequently been called oesophagismus, but the explanation is not a satisfactory one. (3) Pyrosis or water-brash is a painful sensation in the epigastrium, consisting of a sense of burning, which is generally attended with the rising of a ((uantity of clear watery and strongly alkaline fluid into the mouth. An attack of pyrosis may last from a few minutes to many hours, with alternating remissions and exacerbations, and is most prob- ably caused by a spasm of the cardiac end of the stomach when its contents are very acid, thus arresting the secretion of saliva in the oesophagus. (4) Bulimia is a feeling of hunger, which is abnormal in its period of occurrence or in its intensity, and which is appeased only for a short time by taking food. (5) Polydipsia is an excessive feeling of thirst, and is a constant symptom of polyuria and diabetes, and is an occasional symptom in hysteria. (6) Excessive voluptuous feelings arise without any exciting cause in both sexes, and are associated with the erections and ejaculations which accompany normal coitus. These sensations may be caused by a local irritation of the genitals, or by a central disease like tabes dorsalis. (7) Feeling of oppt'ession arises, when general, from overwork or deficient nourishment of the nervous system. It is described by the patient as a feeling of heaviness, dulness, and depression of spirits. A more specific form of oppression occurs in connection with cardiac aff'ections, which will be subsequently described as angina pectoris. b. Visceral Anaesthesia and Analgesia. Very little is known with regard to diminution or loss of visceral feeling. The normal functions of the viscera are performed without 134 GENERAL SYMPTOMATOLOGY. definite sensibility, although a diffused visceral sensibility contributes greatly to our feeling of comfort and well-being, and it is probable that diminution of visceral sensations contributes in a corresponding degree to our o-eneral feeling of bodily discomfort. Visceral anaesthesia is best defined'^in the organs which are most in relation with external forces, such as the larynx, stomach, sexual organs, and rectum. (1) Ancestliesia of the laryngeal and bronchial branches of the vagus renders titillation and the consequent reflex act of coughing impossible. In this condition catarrhal secretions fail to be expelled, and may by their accumulation cause suffocation. (2) Ancesthrsia in the territorg of the gastric branches of the vagus gives vise to polgj^hagia, & condition in which an unusual quantity of food must be taken before the feeling of hunger is appeased, or in which the feeling of repletion is never obtained however much food is taken. The experiments of Brachet, Arnold, and others have proved that, on section of the vagi, animals continue to eat until the oesophagus is filled with food. (3) Ancesthesia of the sexual feelings is most frequently observed in the female sex. Complete absence of voluptuous feelings in hysterical females, along with diffused or circumscribed cutaneous angesthesia, is most probably due to anaesthesia of the mucous membrane of the vagina. Anaesthesia of the genitals is observed in the male sex as a result of sexual excesses or onanism, or as a symptom of chronic affec- tions of the spinal cord, such as spinal meningitis and tabes dorsalis, or in the absence of any appreciable cause. In such cases the electrical sensibility of the glans penis and of the external genitals is diminished, and the power of erection is lost, constituting impotency ; or the loss of reflex irritability arrests the secretion of semen and abolishes the power of ejaculation, a condition named asperinatisin. (4) Ancesthesia of the mucous membrane of the rectum, which is a frequent symptom of grave organic diseases of the spinal cord, permits the stools to pass unconsciouslv. (5) Ancesthesia of the mucous membrane is probably present in the early stages of many cases of locomotor ataxia, and causes great toler- ance of the bladder to its contents. The bladder may become greatly distended without giving rise to the desire to micturate. Anaesthesia of the mucous membrane of the urethra produces a condition in which the urine may pass in a full stream without the knowledge of the patient. 5. Sensory Disorders of the Special Senses. The consideration of this part of the aesthesioneuroses is reserved for special mention in a later part of this work. SECONDARY OR COMPOUXI) J^STHESIOXEUROSES . 135 II. The Secondary or Compound ^Esthesioneuroses. The sensory conducting paths unite with each other for the first time on reaching the common centre of sensory connections — the scnsorium commune; and molecular change in this centre is the correlative of the compound feelings and cognitions, while an abnormal molecular discharge from this centre is the correlative of the disorders of the compound feelings comprised under the name of the secondary aesthesio- neuroses. But we have seen that the cortex of the brain forms also a common centre of motor connections, a motorium commune, and that there is no clear dividing line between the common sensory and common motor centre ; and it may, therefore, be expected that the disorders of the compound feelings will not be separated by a sharp line of demar- cation from the disorders of the compound movements of the body. As a matter of fact, the disorders of the elementary feelings, of the com- pound feelings, of the compound movements, and of the elementary movements merge into one another by insensible gradations, and it is impossible to draw anything like a clear-cut division between them. We shall, therefore, describe briefly in this section a few of the disorders of the compound feelings and movements under the name of psychical disorders, and without attempting to differentiate clearly between the two sets of phenomena : (1) Pseudo-cesthesia is a generic name given to sensations and per- ceptions experienced in the absence of any adequate irritation of the peripheral end-organs or of the conducting paths, the condition of their production being a molecular discharge from the common sensory centre. When a sensation of this kind is experienced, and gives rise to an erroneous perception of external objects and relations, it is named an illusion; when it gives rise to an objective sensation in the entire absence of an external cause, it is termed a hallucination ; and when the patient forms such a distorted conception of the properties and relations of things actually existing that he is led to a false conclusion with regard to them, the condition is called a delusion. (2) Unconsciousness. — The molecular activity .of the sensorium commune is intermittent, and under normal conditions it is suspended for several hours every night, and during this time consciousness is abolished. This constitutes sleep. If the subject cannot be aroused to consciousness by the application of ordinary stimuli, the condition is called somnolence or stupor ; and if the unconsciousness become so profound that the subject cannot be aroused by the strongest external stimuli, the condition is called coma. 136 GENEKAL SYMPTOMATOLOGY. (8) Subconscious and Semiconscious Psychical Actions. — Between the active consciousness of a healthy person after being restored l.y sleep and complete insensibility there are all degrees of diminution of sensibility. It is well known that a person whose attention is strongly directed to a particular subject is insensible to ordinary stimuli. A more advanced degree of diminution of the activity of consciousness is manifested by persons suffering from great fatigue and loss of sleep. Under such circumstances a person may walk about in a half-conscious state, and a similar dazed condition is frecjuently observed after epileptic seizures. The patient may perform complicated motor actions Avhile in a totally unconscious condition, as is seen in somnambulism, the mes- meric state, or the narcosis caused by chloroform and similar agents. Unconscious conditions are, indeed, frequently associated with motor disturbances. When the inliil)itory action of the highest coordinating centre is removed, the functional activity of tlie lower centres may be increased. Many atrocious murders are committed during the period of semiconsciousness which sometimes follows an epileptic seizure, and it is well kuoAvn how fierce and brutal many men ))ecome during the semi- conscious condition induced by alcoholic excess. In delirium^ again, the highest form of consciousness is in abeyance, while the lower, earlier organized forms are abnormally active. The patient, for instance, is unable to sleep, and yet he is only partialh^ conscious of surrounding objects and events ; he is subject to illusions, hallucinations, and delu- sions, and motor disturbances are manifested bv great restlessness and incoherent speech. It is probal)le that in delirium the stock of irritable matter in the gray substance of the cortex is much exhausted, and that what remains manifests an undue degree of irritability, so that the protoplasm gives out energy either spontaneously or on the application of slight stimuli, while functionally there is a dissolution from the later to the earlier acquired feelings and experiences. But although the patient is only semiconscious in delirium, yet his mental experiences during that time may be subsequently remembered with painful intensity. This also occurs in dreams. The patient is wholly unconscious of external impressions at the time, but he is par- tially conscious of a succession of feelings and images, cither of a joyful or a painful kind, which may be subsequently revived in memory with greater vividness than almost any of his mental experiences during waking hours. Dreams are frequently accompanied by motor disturb- ances, such as vocalization and articulate sounds. The most prominent feature of the night-terrors of children is the outward expression of extreme terror by which the attack is manifested. The partial uncon- sciousness which precedes or follows an epileptic seizure is often asso- SECONDARY OK COMPOUXD .ESTH ESIONEUROSES . 137 ciated with the (nitward manifestations of one of the emotions, and sometimes by a corresponding inward feeling. The aura of an epileptic attack may be a guilty expression, and the patient may subsequently be able to remember that innnediately before the attack he experienced a feeling as if he had been guilty of an infamous action. What appears to be an increase of consciousness often results from a diminished activity of the higher sentient centres. Increase of the normal desires and appetites sometimes results from a ])eripheral irritation, but a person is liable to an illegitimate indulgence of the passions when the moral feelings are weakened, and tem])tation is apt to be strongest during states of mental enfeel)lement from cerebral exhaustion. It is then also that remorse for previous indulgence is liable to become (|uite dis- proportionate in its intensity to the degree of guilt, and may be experi- enced in the absence of any guilt to atone for. The depressing emotions, such as fear and anger, are also liable to become excessive during states of nervous exhaustion, and it is a nuxtter of common ol)servation that a person who is in feeble healtli is often very irascible, while others are easily excited to laughter or tears. Experiments on animals have show n that a nerve whose nutrition is lowered discharges its energy more readily than one whose nutrition is perfect, and similarly when the nutrition of the sensorium commune is defective it responds to stimuli of less intensity than Avhen its nutrition is normal. (4) Double Consciousness! ; Periodic Amnesia. — Closely allied to somnambulism and the mesmeric sleep is the curious condition which has been called double consciousness, or periodic amnesia. In this con- dition the subject is liable to periodic seizures, which may last from some hours to as many days, and during which there is complete for- getfulness of the feelings and events of ordinary existence, although rational thou<>;lit and action still remain. (5) Abnormal States of Conscious7iess. — There are some abnormal elementary feelings which must be regarded as qualitative rather than quantitative alterations of consciousness. As examples of these, may be mentioned ('/) headaclie, (b) vertigo, and (c) fainting. To the con- sideration of these nuiy be added a few remarks on {d) abnormal appe- tites and emotions. (a) Headarhe. — Although headache is an excess of painful feeling, yet it cannot as a rule be regarded as an excess of any normal feeling, or of any feeling which can be excited by the application of external stimuli. From this statement neuralgic, rheumatic, and pro])a))ly some other forms of headache must be excepted, but what is generally known as a nervous headache is a truly abnormal feeling, and must be experienced by a person before he can form an adequate idea of it. 138 GENERAL SYMPTOMATOLOGY. Such headaches are caused by changes of circulation in the brain, the circulation of poisons in tlie blood, or they may arise spontaneously at recurrino- intervals. It is probable that in all of them there is an alteration of tlie irritability of the cells and fibres of the sensorium. Recurring headaches are generally associated with vaso-motor phe- nomena in the regions of distribution of the cervical sympathetic nerves, but it is probable that these are the results and not the cause of the sensorial disturbance. Such headaches are regarded by Dr. Hughlings Jackson as a sensory epilepsy and as being dependent upon a discharge from the sensory portion of the cortex of the brain. {!)) Vertigo is a sensation of swimming in the head, during which surrounding objects appear to oscillate before the eyes, or rotate in a definite direction, and which is also accompanied by a sense of stag- gering or of rotation of the body. A^ertigo a})pears to be the subjec- tive correlation of want of coordination between the various muscular contractions necessary for adjusting the body to the different objects which surround it in space. It is a prominent symptom of those dis- eases in which the automatic mechanism for maintaining the erect posture is deranged, such as affections of the cerebellum and Meniere's disease. The position of the body in space is largely determined by the association of objects seen with the appreciation of the position of the eyes and head. Displacement of the positi(m of the eyes, such as occurs in paralysis of one or more of the recti muscles, or of the posi- tion of the head, such as occurs in rotation of the head with conjugate deviation of the eyes, and in the compulsory movements to be subse- quently described, is also accompanied by severe vertigo. This symp- tom frequently attends visceral disease, as dyspepsia, and it is then probably caused by vaso-motor changes influencing the cerebral circula- tion. This opinion is rendered all the more probable from the fiict that vertigo is a troublesome symptom both of ansemia and congestion of the brain. Vertigo is usually accompanied by a motor phenomena in the region of distribution of the pneumogastric, such as feeble and irregular pulse, irregular respiration, and vomiting. (f) Fainting is a deadly feeling caused by sudden anaemia of the brain occasioned by severe loss of blood or cardiac failure. It also is attended by gasping respiration, and frequently accompanied by vomitino;. {d) Ab>ior)nal Appetites, Amotions, and Impulses. — Drunkenness may be regarded as an abnormal appetite, especially when it assumes the aggravated form of dipsomania ; but the most remarkable example of an abnormal appetite is afforded by the condition described by Westphal and others as perverted sexual instinct (contrare sexualemp- SECONDAET OR COMPOUND .ESTHESIONEUROSES . 139 fimlung). This condition is defined by Westphal as "a congenital perversion of the sexual instinct with retained consciousness of the morbid nature of the condition," and the recorded cases show that some pei'sons are attracted in their sexual desires exclusively by indi- viduals of their own sex. The most remarkable of the abnormal emotions consist of a morbid dread experienced in the absence of any circumstance or event which could l)e thought in the remotest deoree capable of inducing such a feeling. Some persons experience an un- conijuerable feeling of dread when they are alone in an open space [am/oraphohia) ; others have the same feeling when in a narrow lane between two Avails {claustrophobia). Some people have a morbid dread of society (anthrophohia), while there are some men who only experi- ence an aversion to the society of women {(lynephohia). Some persons are totally unable to sign their names in the presence of a witness. A gentleman in business once told me that while able to keep accounts and attend to his business as well as ever, he found himself totally unal)le to sign a check if his clerk made a sudden demand for one. Suicidal, homicidal, and other morbid impulses are liable to become uncontrollable during periods of great nervous exhaustion, and when the highest manifestations of consciousness are in abeyance. Atrocious crimes are usually committed by persons during the period of depres- sion which follows a prolonged carouse, or when the individual. is in a state of semi-stupefaction, either from alcohol or as a sequel to an epileptic seizure. CHAPTER Y. GENERAL SYMPTOMATOLOGY {continued). B. TKOPHONEUROSES. The degenerations of the nervous system having ah-eady been con- sidered, we shall now proceed to describe the degeneration of muscles which result from nervous disease. I. Neueotic Atrophy of Muscle. Neurotic atrophy of muscle may be divided into three stages, namely: 1, Simple atrophy; 1, Atrophy with nuclear proliferation; 3, Cirrhosis of muscle. 1. Simple Atrophy. In simple atrophy and the early stage of the severer forms of atrophy, the muscular fibres undergo a simple diminution in size, t ■ c Atrophv of Muscular Fibres from a Case of Infantile Paralysis. (After Havem.) «, Fibres of normal size, showing multiplication of nuclei ; 6, simple atrophy, with granular degenera- tion ; c, advanced granular degeneration, with atrophy. without presenting any degenerative changes. The longitudinal and transverse striations are at times as well preserved as in health (Fig. NEUROTIC ATROPHY OF MUSCLE. 141 G4, a), and not a trace of fatty degeneration can be discovered. It would appear that the fibrilhe of which the fibre consists are diminished in number, but those which remain do not seem to be sensibly dimin- ished in size. At other times the striation becomes less marked and more delicate than in health, probably owing to a diminution in the length of the sarcous elements of the contractile disks (Fig. G-t, h). The substance of the contractile^ disks may also present a finely granu- lar aspect, which appears to be the first indication of the profound chemical change which this substance subsequently undergoes. 2. Atrophy with Xud'ar Proliferation. When the muscle is examined from three to five weeks after the injury the contents of the fibre are now seen to have undergone a finelv granular degeneration (Fig. 64, c). The granules at first consist of altered protein, but they soon become distinctly fatty. The primitive fibrils now disappear, and only small fragments of the fibre present, here and there, either transverse or longitudinal striation. In addition to these changes the nuclei or muscle corpuscles are multiphetl. and in the later stages of atrophy the sarcolemma may become almost filled Avitli masses of nuclei Avhich are surrounded by granular and fatty detritus, while the contents of the fibres are completely disintegrated (Fig. 65, h h). The nuclei of the endomysium also seem to be more numerous than in health. 3. Cirrhosis of Muscle. The nuclei of the endomysium, now greatly increased in number, elongate into fibres which form narrow bands of fibrous tissue running parallel to the direction of the muscular fibres, and cicatricial contrac- tion of this tissue completely destroys the remnants of muscular fibre and gives rise to organic shortening of the l)and of fibrous tissue which now represents the muscle. These bands of filirous tissue contain many oat-shaped nuclei and connective-tissue cells (Fig. 65, a a) which may become distended with flit, and these fat cells may become so abundant that the original volume of the muscle may be maintained or even exceeded. It is now fully ascertained that active neurotic atrophy of muscle never occurs except when the spino-neural mechanism is injured, either by disease of the ganglion cells of the anterior horns of the cord and the corresponding cells in the medulla oblongata and pons, or of the efferent fibres which connect these with the muscles. A moderate 142 GENERAL SYMPTOMATOLOGY, decrree of muscular atrophy may also be caused by irntation of the afferent fibre of the reflex arc. Whether the same cell exercises both trophic and motor functions, or there exist separate cells for each func- tion is as yet undetermined. It would appear that a destructive lesion of the cranglion cells, or of the efferent fibres which connect these with the muscle, causes both motor paralysis and active atrophy, while in Fig. 65. Infantile Paralysis. (After Havem.) a a, Excess of connective tissue, containing a large number of conuective-tisBue and fat cells ; 6 b, atro- pliied muscular fibres, containing a large number of nucli^i ; c, simple atrophj- of muscular filjre severe cases there is also rapid loss of the faradic contractility. A. certain degree of wasting may occur in paralyzed muscles Avhen the lesion is restricted to the cerebral mechanism, but this form of atrophy arises simply from disease of the muscle, and differs entirely from the active atrophy which has just been described. CUTANEOUS TROPHIC AFFECTIONS. 143 II. Cutaneous Trophic Affections. 1. Ciititneous Eruptions in Lesions of Peripheral Nerves. Erythematous patches are often observed on the extremities after traumatic lesions of the peripheral nerves, on the root of the nose and forehead in trigeminal neuralgia, and on the hand in cases of brachial neuralgia. Erythema often arises in the course of digestive disorders, and it is then most probably of reflex origin. The urticaria which is caused by the stings of insects and nettles, and that which arises in the neighborhood of the puncture in subcutaneous injections, seems to indicate that this eruption is often, if not always, of nervous origin. Vesicular eruptions are often observed after injury to nerves. Ecze- matous eruptions are often associated with neuralgic pains in the area of distribution of an injured nerve, and eczema of the whole side of the face has been observed to accompany a severe attack of trigeminal neuralgin. Herpes zoster often accompanies a severe attack of neuralgia. Its favorite seat is the skin covering one or more of the intercostal spaces, and the neuralgia which accompanies it generally begins and terminates with the eruption ; but, in aged people, the pain, which is very intractable, continues long after the eruption has disappeared. Herpes zoster of the face occurs in trigeminal neuralgia. It may appear on any part of the face, but is most frequent on the forehead. When the palpebral nerves are affected the eruption spreads over the upper eyelid, and the conjunctiva is inflamed ; and when the frontal and its nasal branches are likewise involved, the iris and other structures within the eyeball are inflamed, and the disease may then cause serious damage to the eye. Herpes zoster has also been observed in the area of distribution of various spinal sensory nerves when the nerve is com- pressed by aneurism, cancer of the vertebra, or other tumors. Evidences of neuritis of the aifected intercostal nerves have been found in cases that died whilst the patients were suffering from intercostal herpes zoster. Pemphigus bulh^ sometimes develop with great rapidity over various parts of the surface supplied by the cutaneous branches of an injured nerve. After section or injury of nerves, the skin frequently becomes dry, harsh, and scaly ; and a case is reported by Eulenburg in which several branches of the brachial plexus were injured and compressed in consequence of a dislocation of the humerus, and in which ichthyosis of the skin of the affected extremity had supervened. After traumatic injuries of nerve-trunks the skin often undergoes atrophy, loses its Avrinkles, and becomes smooth and glossy, and conse- 144 GENEKAL SYMPTOMATOLOGY. quently this condition has been named " glossy skin " by Paget. " In well-marked cases," this author says, '' the fingers Avhich are affected (for this appearance may be confined to one or two of them) are usually tapering, smooth, hairless, almost void of wrinkles, glossy, pink or ruddy, or blotched as with permanent chilblains. They are commonly also very painful, especially on motion, and pain often extends from them up tlie arm." Glossy skin is often met with in injuries of the ulnar nerve of the brachial plexus and in the upper extremity ; the palm of the hand is the part which usually suffers, while in injuries of the nerves of the lower extremity the dorsum of the foot appears to be the part most liable to be attacked. Patches of leucoderma, with aneesthesia of the affected skin, have been observed on the face in trigeminal neuralgia, and over other parts of the body after injuries to large nerve trunks. Patches of highly pigmented skin, with anaesthesia, have also been found scattered irregularly, but symmetrically, all over the body ; these also being doubtless of nervous origin. The early occurrence and the severe degree of anaesthesia in the tubercular variety of leprosy, as well as the manner in which it pro- gresses from the periphery towards the central parts of the affected limbs, Avould alone indicate that disease of some part of the nervous system is a prominent part of the affection, and characteristic anatomical changes have been found in the nerve-trunks. Morbid changes have also been discovered in the spinal cord and brain, but it is probable that disease of the nerve-trunks takes the most active part in causing the local symptoms. 2. Cutaneous Eruptions in Diseases of the Spinal Cord. Cutaneous eruptions of various kinds occur in cases of chronic mye- litis, but they are most frequently met with during attacks of lightning pains in tabes dorsalis. These eruptions consist of patches of urticaria, vesicular eruptions of which herpes is the most common, and papular eruptions like lichen planus, and they ai-e always limited to nerve terri- tories affected with neuralgic and lightning pains. Several cases of pem- phigus in connection with spinal disease have been recorded by Chovstek and olhers. A case is recorded l)y Balmer in which an attack of pem- phigus occurred in the course of progressive muscular atrophy. 3. Cutaneous Eruptions in Diseases of the Brain. Herpes is not infrequently associated with hemiplegia, but it is doubtful whether there is anything more than an accidental connection between them. Two cases are reported bv Dr. Duncan, in each of TROPHIC DISORDERS OF THE XAILS AXD HAIR. l-i.") Avliich an eruption of herpes appeared on the affected side simulta- neously with the motor paralysis. Several cases are reported in which a pemphigus eruption appeared on one of the paralyzed extremities in hemiplegia of central origin. III. Trophic Disorders of the Nails and Hair. 1. Trophic Disorders of the Nails and Hair in Lesions of the Nerve-trunks. Traumatic lesions of nerve-trunks in which the nerve is not com- pletely divided, are followed by various deformities of the nerves. The nails become greatly curved — both laterally and longitudinally — fur- rowed, dry, and cracked at their extremities, and of a yellowish-brown color. These deformities may also occur in connection with neuralgia and idiopathic neuritis of sensory nerve-trunks. Local affections of the hair often occur in man after traumatic lesion of nerve-trunks, or in connection with idiopathic neuritis and neuralgia. The hairs over the region of distribution of a nerve affected with neuralgia have some- times been observed to be hypertrophied and even increased in number ; but, as a rule, the effect of neuralgia upon the hair is to make it brittle, and to cause it to fall out in considerable quantities. Localized gray- ness of the hair is often associated with ophthalmic neuralgia, and it may also involve the eyebrow of the affected side. This grayness sometimes assumes an intermittent character, increasing during and sometimes after an acute attack of pain, the color becoming partially restored in the interval between the paroxysms. In glossy skin the surface becomes hairless. 2. Trophic Disorders of the Nails and Hair in Spinal Disease. The nails may become deformed in cases of acute and chronic myelitis, but the most remarkable change to which they are liable in spinal diseases occurs in locomotor ataxia. In the course of this disease the nails of the great toes sometimes fall oft" spontaneously, and are then rapidly replaced by a new and perfectly normal nail, which may In its turn ftill off a few months later, and this process may occur in the same nail several times in succession. The falling off of the nail may be preceded for some weeks by a dull pain, or by a feeling of uneasi- ness in the toe, and then the nail falls oft' without being accompanied either by suppuration or by apparent ulceration of the matrix. In other cases the patient observes that the nail of one great toe, and a few days later that of the other, suddenly become of a dark blue color 10 146 GENERAL SYMPTOMATOLOGY. from subungual effusion of blood, and a few days afterwards the nail falls off, witliout being preceded or accompanied by pain or other warn- ing. The nails have also been known to fall off in sclerosis in patches. An* increased growth of hair has occasionally been observed in cases of chronic myelitis. 3. Trophic Disorders of tJie Nails and Hair in Cerebral Diseases. In cases of hemiplegia the nails become curved and cracked, but the trophic disorders to which they and the hair are liable in cerebral dis- ease are by no means so well marked as in spinal affections and lesions of nerve-trunks. IV. Bej)Sores and other Destructive Processes. 1, Decubitus Aeutus. — Some days or even hours after the occurrence of a severe spinal or cerebral lesion, or aftei- a sudden exacerbation of these affections, one or several erythematous patches appear over the sacrum and gluteal regions, the trochanters of the femur, ankles, or other parts subjected to pressure. In -these patches, which are of variable extent and irregular form, the skin assumes a rosy hue, or becomes dark red or violet, but the color disappears momentarily on pressure with the finger. After a period which varies from twenty- four to forty-eight hours, the central part of the erythematous patch is covered with vesicles or bullae, the contents of which, at first colorless and transparent, become more or less opaque, reddish, or brown colored. Under favorable circumstances the vesicle may wither, dry u]), and dis- appear, and the part recover without further change; but in most cases the vesicles burst, and leave ill-looking ulcers, the bases of which are composed of the true skin in a state of ])hlegmonous inflammation, and infiltrated with blood. The base of the ulcer soon perishes by gan- grene, the neighboring skin becomes inflamed to a greater and greater extent, and the gangrenous destruction extends deeper and deeper, laying bare and including in its destructive operation muscles, tendons, fiiscise, hgaments, and even the subjacent bones. One of the most re- markable characteristics of the affection is the extreme rapidity of its development, the entire cycle of changes being completed in a few days. Cystitis and hsematuria are not infrequent complications of this condi- tion, and the muscles of the lower extremities become the subjects of rapid atrophy. Metastatic abscesses now occur in the kidney, lungs, and other viscera, the accompanying fever assumes a remittent type, and the patient dies of septic fever. In some cases the gangrenous process extends to the sacral bones, and with the destruction of the BEPSdRES AND OTHER DESTRUCTIVE PROCESSES. 147 sacro-coccygeal ligament the vertebral canal is opened, and thus the ichorous discharges find access to the fatty cellular tissue which sur- rounds the dura mater, and by penetrating this membrane they may even make their Avay to the arachnoid cavity. This grave accident is followed by a simple purulent or an ichorous ascending meningitis, which rapidly reaches the base of the brain, and is soon fatal. 2. Chronic Decubitus. — In chronic diseases of the spinal cord the portions of skin subjected to pressure in the recumbent posture assume a dark red color, and at times become covered with superficial ulcera- tions. After a time a black spot appears on the reddened portion of skin, and, if i)re8sure is contiimed, it enlarges rapidly, and the afiected skin dries up into a hard leathery mass. In a short time a boundary line of inflamniation forms around the gangrenous portion of skin, and the latter may, under proper treatment, be thrown oif, leaving a more or less healthy granulating surface, which may sometimes cicatrize. But if the pressure be continued, or if the primary disease of the ner- vous system undergo a fresh exacerbation, the ulcerated surface assumes a dark violet color, the gangrene spreads rapidly, and all the destructive changes characteristic of acute bedsore make their appearance and soon lead to a fatal result. 3. SyrtDiietrical Gangrene and Local Asphyxia. — This disease, which was first described by Raynaud, generally involves the fingers, and less frequently the toes, tips of the nose, and external ear. The affected parts become suddenly white, cold, bloodless, and insensible, and motor power is diminished. The skin is wrinkled and shrunken, the ends of the fingers appear thin and conical, and, when the whole exti-emity is affected, the pulse is feeble or imperceptible. After some months reaction sets in : the parts then become congested, of a violet or livid color, intensely painful, and the seat of troublesome itching, while vesicles form which are filled with a sero-purulent fluid, and, on bursting, leave the cutis excoriated. Even at this stage recovery may take place, but the attack usually recurs, and ultimately the parts undergo a true nmmmification and the last phalanges of the fingers drop off". The disease occurs usually in chlorotic and nervous persons, and is seldom met with in children and old people. It appears to be caused by a spastic ischtemia of the arterioles. 4. Perforathig Ulcer of the Foot. — This aff"ection, as seen in the foot, is less like an ulcer than a sinus. It usually presents itself as a small aperture, which leads directly by a narrow channel to exposed and diseased bone. From this opening there is little or no discharge ; the skin surrounding the orifice is greatly thickened by superimposed layers of epidermis, and, indeed, the formation of a large corn appears 148 GENERAL SYMPTOMATOLOGY. always to precede the destructive process. The ulcer is, as a rule, insensible to ordinary stimuli, and there is no pain when the patient is at rest ; but considerable pain may be caused by pressure on the sole during locomotion, and the patient often suffers from severe lightning painsln the lower extremities. Not only are the tissues surrounding the wound insensible, but there is also, as a rule, more or less complete cutaneous anaesthesia and analgesia of the whole of the sole of the foot, and sensation may be diminished in the region of distribution of one or more of the cutaneous nerves as far up as the calf or knee. The surfiice is usually cold in the anaesthetic area, and the extremity is likewise apt to become livid on slight exposure, Avhile it is prone to attacks of inflammation or of eczema. These inflammatory attacks sometimes implicate the subcutaneous tissues ; the limb then becomes greatly swollen and oedematous, and the attack occasionally termin- ates in suppuration. Lesions of the articulations of the foot fre- quently accompany this affection, and not only is the joint in direct relation with the wound diseased, but it is also not uncommon to meet with more or less complete ankylosis of all tlie phalangeal, metatarso- phalangeal, and tarso-metatarsal articulations, while sul)luxations of these joints may take place in other cases. It is, however, pr()l)ab]e that extensive disease of the bones and joints of the foot o»ily occurs when perforating ulcer is a symptom of locomotor ataxia. The nails assume a brownish color ; they become greatly thickened, curved longitudinally and laterally, furrowed, dry, and cracked. The skin of the leg be- comes at times pigmented, and there is an increase in the growth of the hair, while the foot is bathed in sweat which has a permanently fetid odor. The ulcer is generally situated over the metatarso-phalan- geal articulations, most frequently over those of the big and little toes. There may be as many as three ulcers on one foot, and when both feet are affected the disease is generally symmetrical. Perforating ulcer has on rare occasions been met with in the hands. The disease is essentially chronic; the ulcers may, under favorable circumstances, remain stationary for a long time, and may even heal under prolonged rest, but a relapse readily occurs Avhen the patient begins to walk. The most recent observations on perforating ulcer of the foot show that it is very frequently, if not always, associated with other symptoms of locomotor ataxia. It was known a long time ago that this form of ulcer was often accompanied by shooting pains and anaesthesia in the lower extremities, while strabismus and other ocular troubles Avere also mentioned as being present in such cases. It is now found that patients with perforating ulcer also suffer from gastric crises, arthropathies, swaying movements on closing the eyes, tottering or unsteady gait, and BEDSORES AND OTHER DESTRUCTIVE PROCESSES. 149 absence of the patellar-tendon reactions. Perforating ulcer is associated with the neuralgic form of locomotor ataxia, and motor disorders do not form prominent features of such cases. It may be one of the earliest symptoms of the disease, and may even precede the anesthesia of the loAver extremities, so that its association with locomotor ataxia is not always readily made out. In a case wliich was under the care of my colleague, Mr. Hardie, there was some degree of anaesthesia of the lower extremities, but the patellar-tendon reactions were exagger- ated, and I was about to conclude that the case was not one of loco- motor ataxia, A closer examination, however, showed that the patient had suffered from diplopia, and that the pupils failed to react to light, but reacted to accommodation. The presence of these symptoms ren- dered it very probable that the patient was in the early stage of loco- motor ataxia, notwithstanding the patellar-tendon reactions were ex- aggerated. Dengenerative lesions of the nerves have been found, on microscopical examination, in several cases of perforating ulcer. 5. Unilateral Profiremive Atrophy of the Face {Heniiatrophia Facialis Progressiva). — This disease has been observed about twice as often in women as in men, and it generally begins between 10 and 15 years of age, although it has occasionally been observed as early as 2 and as late as 30 years of age. The characteristic phenomena of this disease may be preceded for some time by such symptoms as a local herpetic eruption, toothache, tearing pains in the head and superior maxillary region, ei)ileptiform attacks in which the spasms are some- times more or less limited to the side of the face, an attack of hemi- plegia, spasms of tlie masticatory muscles, and hypersesthesia with parsesthesia in the side of the face, which is afterwards the subject of atrophy. The first definite symptom to attract notice is a peculiar discolora- tion of circumscribed areas of the skin. Small spots of a white color and slightly depressed appear on the side of the face, and these gradu- ally spread so as to coalesce into a patch of considerable size. The affected area may now assume a yellowish or brownish tint like that often observed in cicatrices after burns, the skin over them becomes thin and emaciated, the subcutaneous fat disappears, and the side of the face becomes deformed by pits of greater or less size and depth. On the affected side the eyeball often sinks back into the orbit from disappearance of the orbital fit, the palpebral fissure is narrowed, tiie beard, eyelashes, and hair of the head become gray and undergo other structural changes, and the secretions of the sebaceous follicles is arrested, but the functions of the sweat glands appear to be normally l^Q GENEKAL SYMPTOMATOLOGY. performed. lu advanced cases the affected skin feels irregular and atrophied, and it may assume the form of a cicatrix, but does not become adherent to the underlying structures. Cutaneous sensibility is not, as a rule, much affected, hut patients sometimes complain of various parfesthesise in the atrophied portions of skin, and others have suffered from neuralgiform attacks, while in one case partial ani^sthesia, and in a few others hypertesthesia was present. The muscles are not usually implicated in the atrophy, but in a case observed by Eulenburg and Guttmann the masticatory muscles on the affected side were relatively feeble and emaciated, in a few cases atrophy of one half of the orbicular of the mouth w^as observed, and in other cases one half of the tongue, the veil of the palate, and the uvular were found atrophied, but the muscles always gave normal elec- trical reactions. Romberg reports a case occurring in an unmarried woman, aged twenty-eight years. The left side of her face had gradu- ally atrophied as the result of extensive suppuration on the left side of the neck, which had burst through the tonsil. Every feature, including the brow, eye, nostril, lips, cheek, and chin, as well as the left half <»f the tongue and left arch of the palate, was smaller than those on the opposite side. The large arteries of the face are generally unaltered in size, and the tone of the small arteries is retained or increased. The atrophied parts are generally capable of blushing, and also redden under local electrical excitation. The temperature is the same on both sides. The bones of the face liave been found decidedly diminished in volume. The upper and lower maxillary Ijones and the cartilages of the nose are often atrophied, especially Avhen the disease begins at an early age. Romberg was the first to give an accurate description of this affection, and he classified it amongst the trophoneuroses. The trophic fibres are not likely to run in the motor branch of the fifth nerve, inasmuch as paralysis and atrophy of the masticatory muscles, although occasionally present, are never prominent symptoms. Cases have been described by Seeligmiiller and Brunner, in which the symp- toms appeared to have been caused by disease of the cervical sympa- thetic, but it is probable that, as suggested by Miiller, the lesion is situated in the medulla oblongata. This disease is, with occasional long pauses and recommencements, a progressive one, and no treatment has hitherto been of any avail. 6. Neuroparalytic Ojjhthahnia.—Tlm affection begins with conges- tion of the conjunctiva, which is followed by profuse secretion of mucus or pus, nisensibility and opacity of the cornea, and a pseudo-mem- branous exudation of the iris. In a few days ulceration and perfora- ARTICULAR AXD OSSEOUS AFFECTIONS 151 tion of the cornea may oecuv, -which is followed by escape of the humors and collapse of the eye. Several hypotheses have been advanced to account for this destruc- tive inflammation of the eyeball, but the most probable is that it is due to irritation of the trophic fibres which descend from the casserian tranulion to the eyeball. 7. Simple Glaueovia. — Experiments on animals have shown that irritation of the nucleus of the trigeminus in the medulla, or of the nerve itself, is foUow^ed by increase of the intraocular pressure, caused by augmented secretion of the aqueous humor. As a result of the high tension the iris and lens are pushed forwards, and the internal membranes are stretched. It is supposed by many pathologists that glaucoma is produced by a similar mechanism, although this opinion is not accepted by all. V. Nutritive Affections of the Joints, Bones, and Teeth (Articular and Osseous Trophoneuroses). 1. Affections of Peripheral Oruiin. — Traumatic injuries of nerves, in which the nerves are not completely divided, are often followed, any time after the first few days, by disease of the joints, which consists of a painful swelling like that of subacute articular rheumatism. This swelling may attack any or all of the articulations of a limb, and often begins in the joints remote from the injury, so that it cannot be caused by direct extension of inflammation from the wound. After the acute stage is over, the tissues about the affected articulations become thick- ened, and partial ankylosis results, Avhich may ultimately destroy the mobility of the joint. The bones also may become swollen and thick- ened after injuries of nerve-trunks, and in young people the same bones may, at a later period, be arrested in their development. In progressive unilateral atrophy of the face the bones participate, to some extent, in the wasting. 2. Affrctions of Spinal Origin. — Attention has been directed by Charcot and his scholars to the great fre(j[uency with which nutritive changes occur in joints in spinal diseases. These joint affections may be divided into acute or subacute, and chronic arthritis. The acute or subacute form is accompanied hj more or less severe pain, tumefaction, and redness, just as occurs in acute rheumatism. This form occurs in Pott's curyature, traumatic lesions of the cord, idiopathic myelitis, progressive muscular atrophy, acute and chronic poliomyelitis, and disseminated sclerosis. Chronic arthritis is irenerallv observed in association with locomotor ir,2 GENEEAL SYMPTOMATOLOGY. •ifixia Tl.e knee, liip, shoulder, and elbow-joints are most frequently 'attacked, although the fingers and toes are also liable to be affected. When the tarsal bones are affected a characteristic deformity is pro- duced which is named the tabetic foot. The joint disease usually betrins about the same time as the locomotor incoordination, and its onset is accompanied or preceded by severe paroxysms of lancinating pains. The symptoms begin suddenly in the absence of any apprecia- ble external cause, generally witliout pain or febrile reaction, and the joint may be enormously swollen within twenty-four hours from the com- mencement. The general tumefaction disappears after a few days, but a more or less considerable local swelling remains, caused by the accumu- lation of serous fluid in the joint and the periarticular serous bursa-. The fluid, however, disappears from the joint in a few weeks from the onset. In tlie bimigyi form of the affection the joint may recover com- pletely, but in the inalignant form the articular surfaces become greatly altered and so roughened that cracking sounds are heard on movement. After a time the heads of the bones become atrophied and worn, the ligaments become relaxed, and the surrounding muscles ai'e so much atrophied and enfeebled that spontaneous laxations may occur. Fractures. — Spontaneous fractures occur not infrequently in the course of locomotor ataxia. The period of fracture is generally pre- ceded by two or three severe paroxysms of lancinating pains, the limb is then found swollen and presenting all the symptoms of osteo-perios- titis, and it then becomes fractured on the slightest movement, or in the absence of any movement or external cause. The femur is more frequently fractured than any other bone, the seat of fracture being generally the neck, but the bones of the leg, arm, foreai*m, and indeed almost every bone in the limbs and trunk, includinjr those of the vertebral column, have been found fractured. The spontaneous fract- ures of ataxics often reunite very readily and rapidly, with an enormous formation of callus. The earthy phosphates are diminished in the bones which undergo spontaneous fractures, forming sometimes ordy sixty instead of eighty per cent, of the bone as in health, while tlie fatty constituents are enormously increased in amount. 3. Osseous Affections of Cerebral Origin. — In the spastic hemiplegia of infoncy the bones on the paralyzed side are arrested in their devel- opment, being smaller and shorter than tlie corresponding Ijones on the opposite side. In hemiplegic patients arthroi)athies of the joints of the hand and foot are met with which -are like the acute arthropathies of spinal origin. The affection begins with a slight swelling and local increase of temperature, either witli or without pain in the joint, and at times tumefaction and redness are so marked as to resemble the AFFECTIONS OF THE GLANDULAK APPAEATUS. 158 articular affections bf acute rheumatism. The sheaths of the tendons are sometimes implicated along with the joints. These arthropathies occur, as a rule, simultaneously with late rigidity, although it may begin a few days after the attack or at a much later period. 4. Osseous Lesions in the Insane. — In insane patients the bones may either become so soft that they yield readily to pressure, and thus l)roduce various deformities, or so fragile that they are liable to undergo spontaneous fracture, and may be found to crumble readily under the finger and thumb after death. Out of 100 post-mortem inspections of the insane made by Gudden, evidences of fracture were found in 16 cases, and cliiefly in men who had suffered from general paralysis. In three-fourths of these cases there were multiple fractures ; in one case as many as 14, in another 23, and in another 36 fractures. The morbid changes which occur in the bones of the insane are closely related to those observed in the spontaneous fractures of locomotor ataxia. 5. Trophic Affections of the Teeth. — The teeth are not very liable to undergo changes in diseases of the nervous system. They have been known to fall out after an attack of herpes affecting the maxillary branches of the fifth nerve, probably more from necrosis of the bone than from disease of the teeth themselves. Attention has, in recent years, been directed to the fact that the teeth sometimes fall out sud- denly in the course of locomotor ataxia, and in the al^sence of pain or caries of the bone. They have also been observed to fall out in a case of sclerosis in patches. VI. Nutritive and Secretory Affections of the Glandular Apparatus. 1. Cutaneous Secretory Disorders. Various pathological facts appear to prove the existence of cutaneous secretory nerve fibres independently of the vaso-motor nerves. Dimi- nution or absence of the secretion of sweat may at times exist side by side with local increase of temperature and redness, indicating vaso- motor paralysis; and, conversely, the secretion may be increased in amount along with local diminution of temperature and pallor of the surface, indicating vaso-motor spasm. Recent experiments show that peripheral irritation of a divided sciatic nerve in animals induces an increased secretion of sweat in the paralyzed part. The cutaneous secretory neuroses consist of excessive sweating or hi/peridrosis, diminution or absence of secretion or anidrosis, and 151 GENERAL SYMPTOMATOLOGY. qualitative changes which may be grouped under the name o^ paridrosis. The profuse sweating of acute disease, that which results from the action of various toxic agents, and the partial sweats which occur dur- ing hysterical and epileptoid attacks, are doubtless of nervous origin. StTu more striking examples are to be found in the unilateral perspira- tions which have ))een described under the name of Iniperidrosis uni- lateraUs. This affection is sometimes limited to one-half of the head, and at other times extends to the arm of the same side, or even extends over one-half of the body, and is usually associated with severe nervous affections, such as hemicrania, Graves's disease, dialietes mellitus, tal)es dorsalis, and general paralysis of the insane. It is probably caused by lesion of the sympathetic or of the cerebro-spinal centres, with which it is united. Anidrosis is a symptom of fever, diabetes mellitus, chronic 13right"s disease, and of certain skin diseases, and is often associated with grave nervous diseases like general paralysis of the insane. The diminution of ])erspiration caused by various toxic agents like atropine is evidently due to action on the nervous system. A good example of local dryness of the skin occurs in unilateral atrophy of the face, an CaSC), and cathodal opening contraction soon equals or exceeds anodal opening contraction (CaOC = or > AnOC). The following formulge express the qualitative changes in the reaction of degeneration: Weak currents produce during stage of increase CaSC, AnSTe, AnOC, CaOC. ^ledium currents produce during stage of gradual decrease CaSc, AnSTe. Strong currents produce during final stage prior to abolition AnSc. The following diagrams, borrowed from Erb, represent graphically the general relations of motor power, electrical excitability and struct- ural changes of the nerves and muscles which are present in the differ- ent stages of paralysis. The first tliick vertical line or ordinate indi- cates the sudden appearance of paralysis ( IBD )» and the period of return of motor power is indicated by a ( * ), whilst the succeeding ordinates represent intervals of one or more weeks dating from the occurrence of the attack. The undulations in the line representing the galvanic excitability of the muscles indicate qualitative changes in the reactions. In the first degree of the reaction of degeneration (Fig. 66), the electrical excitability of both nerve and muscle falls during the first week, the nerves lose all their electrical reactions during the second week, but the muscles lose only their faradic con- 164 GENERAL SYMPTOMATOLOGY tractility during tliis period, wliilst the galvanic excitability becomes greatly increased and manifests the qualitative changes already de- scribed. At the end of the sixth week there is a gradual return of Degeneration of the Nerve. Fig. 06. Recovery Rapid. Atrophy and Multiplication of Nuclei in the Blusciilar Fibres Regeneration Motility. i ( Galv. I 1 Farad. g ("Galv. and tj -; Farad. Excit- |z; (ability. 10. U 12. Week. motor power, and at the end of the seventh week there is a gradual return of the electrical reactions of the ner\'e and of the faradic con- tractility of the muscle, while the galvanic reactions of the muscle gradually sink, and the (iualitati\e changes disaj)pear until gradually the normal reaction is established. In ''the second degree of the reaction of degeneration the faradic Degeneration of the Nerve. FlO. 67. Recovery Slow Atrophy, etc , of jrviscles. ]{egeneration. 1. 2. 4. i;. 111. 15. 20. 2.'>. :?(i Motility. Galv. Farad. g ( Galv. and •g •< Farad. Excit- >5 (ability. and galvanic excitability of the nerve does not appear until the thirtieth week (Fig. 67), while in the third degree (Fig. 68) the excitability of the nerve never returns, but the galvanic excitability of the muscle THE EXTERNAL KINESIONEUROSES. 165 only becomes finally lost after a pi-olonged period, in some cases extend- ing over a period of two years. A "partial reaction of degeneration" (Fig. 69) has been described by Erb, in which the faradic and galvanic excitability of the aifected 4 \ Galv. ^ ( Farad. =■ (Galv. and ^ - Farad. Excit- 5^ (ability. Degeneration of the Nerve. Fig. (58. No Recovery. Atropliy, Jlultiplication of Nuclei, Cirrhosis t'omplete Disappearance. 1 3. 1(1. 211. o. 80. till. 1(1(1. Week. nerve is diminished, but not abolished, the diminution beino- sometimes only to a slight degree. The faradic excitability of the paralyzed muscle undergoes a diminution corresponding to that of the nerve, but the galvanic excitability of the muscles manifests the quantitative and ([ualitative changes which are so characteristic of the severer form of the reaction of degeneration. Fig. G9. Atrophy and Degeneration of Multiplication of Nuclei the Nerve (?) in the Muscular Fibres. KeKeneratiou Motility. 1 fGalv. (Farad. (Galv. ^ Farad, (ability. and Excit 1. Hypcrkinesis of the 3Iuscles of External Relation. Hyperkinesis of the voluntary muscles consists of abnormal contrac- tions called spasms. Muscular spasms consist of contractions which IQQ GENERAL SYMPTOMATOLOGY. are disproportionate to the degree of external stimulus, or which arise in the absence of external stimulation as the result of morbid irritation. Spasmodic affections may be divided into, a, clonic spasms, in which the muscles are in a state of rapidly alternating contractions and re- laxations ; and, b, tonic spasms, in which the affected muscles are maintained in a state of persistent and equable contraction. a. Clonic Spasms. (1) Tremor is the mildest form of clonic spasm. It consists of slight contractions of groups of muscles by means of which a peculiar rhythmical oscillation of the limbs and trunk is produced. The higher degrees of tremor cause manifest trembling of the limbs and trunk, while fibrillary contractions consist of alternate contractions and re- laxations of individual bundles of muscular fibres which are visible as wavy oscillations under the skin, but do not give rise to any movement of the limb. There are two chief varieties of the severer form of tremor which moves the limbs : one of which persists during repose, and is met Avith in paralysis agitans ; and the other which appears only when the patient makes a voluntary effort, and is observed in sclerosis in patches, (2) Convulsion is the severest form of clonic spasm. It consists of energetic contractions and relaxations of particular muscles or groups of muscles which produce a rapid succession of vigorous movements, and give rise to twitchings of the face, startings of the limbs, and movements of the head and body. If the majority of the muscles of the body are affected with alternating contractions and relaxations, so that extensive and irregular movements of the trunk and limbs are produced, the condition is termed general convulsion, which forms the most prominent feature of epilepsy, uraemia, eclampsia, and hysterical attacks. h. Tonic Spasms. (1) Cramp is the simplest form of tonic spasm, and consists of a persistent painful contraction of a muscle or of a group of muscles. Cramp of the calf is the most common variety of this affection when it IS limited to a single muscle, while tetanus may be taken as the best example when the majority of the muscles of the body are affected. A peculiar modification of cramp is met with in"^ catalepsy. The muscles are moderately contracted, but the resistance they "offer to passive movements may be readily overcome, and the limbs may be made to assume constrained positions which thev retain. From the THE EXTERNAL KINESION EUROSES. 167 manner in which the limbs can be moulded into various positions this condition has been caWed Jiexibilitas cerea. (2) Muscular tension is a state of moderate contraction of muscles which occurs either when they are stretched by passive movements or by a voluntary contraction of their antagonists. This condition is always associated with a certain degree of loss of voluntary power over the affected muscles. (3) Contracture is meant to express any persistent shortening of a muscle, whereby its points of origin and insertion are permanently approximated. The varieties of contraction are myopatliic contracture, when the shortening occurs as a result of disease in the muscle itself; imralytic or secondary contracture, when it occurs in healthy muscles which have their ends permanently approximated owing to paralysis of their antagonists ; and primary or neuropathic contracture, when the muscles are persistently rigid and shortened from abnormal innervation, a condition which is always associated with a certain degree of paralysis. In the last variety the rigidity of the muscle usually disappears during sleep and gradually returns on awakening, and it is almost always in- creased by voluntary and passive movements. Pressure points are frequently observed in spasmodic affections. Pressure upon certain points puts a stop at times to the convulsion when present, and consequently these points may be called pressure- arresting points. In other cases the convulsions are brought on by pressure on particular points, and these may, therefore, be called pres- sure-exciting points. Pressure points of the first kind have been par- ticularly observed in facial spasm, and they correspond, like the painful points in neuralgia, to the various branches of the trigeminus, and are not unfrequently sensitive to pressure. Spasms are caused by increased irritability of some part of the motor nervous mechanism. When the spasm, Avhether it be clonic or tonic, is limited to the area of distribution of particular nerves, the lesion is most probably situated in some part of the spino-neural system, either in the centre or efferent fibre, or in some afferent fibres, the last con- stituting rejlex spasms. Paroxysmal clonic convulsions are caused by irritation of the cortex of the brain, and certain forms of tonic and clonic spasms are caused by irritation of the fibres of the pyramidal tracts. Paroxysmal tonic contractions are most probably caused by irritation of the cortex of the cerebellum. Persistent muscular tension and contracture are caused by disease of the pyramidal tracts, and are associated with paralysis. Dr. Hughlings Jackson explains the pres- ence of tension under such circumstances by supposing that the with- drawal of the cerebral influence allows the tonic action of the cere- 1(38 GENERAL SYMPTOMATOLOGY. bellum to become predominant. Against this theory it is urged that tension is present in cases of transverse myelitis, in Avhich both the cerebral and cerebellar influences are withdrawn. It is therefore prob- able that muscular tension is caused by the removal of the inhibitory action of the cerebrum, owing to disease of the pyramidal tracts, per- mission being thus given for the predominant action of the reflex nervous mechanisms of the spinal cord. 2. Akinesis of the Muscles of External Relation. By akinesis or paralysis of the muscles of external relation is under- stood the diminution or abolition of the power to contract the affected muscles by voluntary effort. The term paresis is used to denote tlie diminution of motor power. Some authors have endeavored to restrict paralysis to its complete abolition, but this term Avill be employed hei-e in a generic sense as embracino; both conditions. Classification. Paralyses of the muscles of external relation are susceptible of being classified according to the nature, cause, and situation of the lesion, the distribution of the paralysis, and the functional disorders of the muscles which accompany paralysis of them. Tliese divisions constitute the — I, pathological, ii, etiological, ill, topographical, iv, clinical, and, v, physiological classification. I. THE PATHOLOGICAL CLASSIFICATION. The diff'erent varieties of paralysis are arranged, according to the nature of the lesion, into rheumatic, syphilitic, inflammatory, and other forms. They may also be divided into organic and functional lesions, according as the morbid changes which underlie the paralysis are or are not capable of being recognized by our present means of research. II. THE ETIOLOGICAL CLASSIFICATIOX. The functional paralyses are not susceptible of being arranged according to the situation of the lesion, and they are therefore usually classified according to tlie cause of the aff"ection. They are usually divided into (1) toxic, (2) febrile and post-febrile, (3) reflex, (4) post- epileptic, and (5) hysterical paralysis. III. THE TOPOGRAPHICAL CLASSIFICATION. The organic paralyses lend themselves readily to a classification according to the situation of the lesion. They may be divided into (i) THE EXTERNAL KINESIONEU ROSES. 169 myopathic paralyses, or those in Avhicli tlie primary disease is situated in the muscles themselves, and (ii) neuroiyathic paralyses, or those in Avhich the primary disease is localized in some part of the nervous system. The neuropathic paralyses, with which we have to do chiefly here, may be subdivided into (1) cerebral, (2) spinal, and (3) neural or peripheral i)aralyses, according as the lesion is situated in the brain, spinal cord, or peripheral nerves respectively. But although this divi- sion is very convenient, a much more important distinction is that which divides them into (1) cerebrospinal and (2) spino-neural paralyses. In the cerebrospinal variety the lesion is situated either in the motor centres of the cortex of the brain or in the pyramidal tracts. In the spino-neural variety the lesion is situated in the anterior gray horns of the spinal cord and their upward continuations in the medulla oblongata, pons, and crura cerebri, or in the fibres of the })eripheral nerves which connect the ganglion cells of these horns with the muscles. It will immediately be found that this topographical division corresponds more or less closely with the divisions of the physiological classification, and this constitutes its chief advantage. It may here be noticed that when the lesion is restricted to one of the physiological tracts of the spinal cord the affection is called a system-disease, and when several of them are simultaneously implicated the affection is called a mixed or indiscriminate disease. Amongst the mixed diseases we shall also include complicated cases of cerebral paralysis. IV. THE CLINICAL CLASSIFICATION. Various names have been given to a paralysis according to its extent and distribution. The paralysis is sometimes limited to a single muscle or group of muscles, or all the muscles supplied by a single nerve or plexus of nerves may be implicated ; when all or almost all the muscles of a single extremity are paralyzed, the condition is called a monoplegia. In other cases the paralysis afi'ects both halves of the body symmetri- cally, and then it generally begins in the lower extremities, and spreads to the trunk and upper extremities. This is the usual form of paralysis Avhich results from disease of the spinal cord, and is termed paraplegia. In other cases the paralysis afi'ects the lateral half of the body, impli- catino; the face, arm, and ler> J- (. b. Late Rigidity. f a. Intermittent Tremor. I b. Choreiform Movements. 2. Tonic & Clonic ' i. Pre-hemiplegic Chorea, ii. Post-hem iplegic Chorea. iii. Spastic Hemiplegia of Infancv. I. Spinal Spasmodic Paralyses. (paraplegia.) II. Cerebral Paralyses. (hemiplegia.) Spasm. 3. Clonic Spasm. I f a. Continuous or Remittent ! Tremors. J j b. Athetosis. [ c. Post-heniiplegic Hemiataxia. III. Mixed Paralysis. B. FUNCTIONAL PARALYSES. (1) Toxic Paralysis. (2) Febrile and Post-febrile Paralysis. (3) Reflex Paralysis. (4) Post-epileptic Paralysis. (.5) Hysterical Paralysis. 172 CxENEKAL SYMPTOMATOLOGY. Table II.— Paralyses from Organic Disease of the Nervous System. TOPOGRAPHICAL DIAGNOSIS. I. Spino-neural Lesions. I. LESIONS OF EFFERENT NERVE FIBRES. II. LESIONS OF AFFERENT NERVE FIBRES. III. LESIONS OF THE ANTERIOR GRAY CLINICAL DIAGNOSIS. I. Atrophic Paralyses. I. NEURAL or peripheral PARALYSES. II. REFLEX ATROPHIC PARALYSIS. III. SPINAL ATROPHIC PARALYSES. 1. Acute Atrophic Spinal Parah'sis of Infants. 2. Acute Atrophic Spinal Paralysis of Adults. 3. Acute Ascending Paralysis. 4. Chronic Atrophic Spinal Paralysis. .5. Peri-ependymal Myelitis. "] 6. Progressive Muscular Atrophy. i 7. Primary Labio-glosso-laryngeal Paralysis. 8. Ophthalmoplegia Externa. 9. (Pseiido-hypertrophic Paralysis.) II. Spasmodic Paralyses. I. spinal spasmodic paralyses. 1. Primary Spinal Spasmodic Paralysis. 2. Compound Spinal Spasmodic Paralysis. 3. Secondary Spinal Spasmodic Paralysis. II. CEREBRAL PARALYSES. 1. Ordinary Hemiplegia. 2. Alternate Hemiplegia. 3. Hemiplegia and Hemianc^sthesia. 4. Hemiplegia, Hemianaasthesia, and Hemianopsia 5. Pre-hemiplegic Chorea. 6. Post-hemiplegic Chorea. 7. Athetosis. 8. Post-hemiplegic Continuous Tremor and Hemiataxia. j 9. Spastic Hemiplegia of Infancy. 10. Unilateral Convulsions and Hemiplet HORNS. (POLIOMYELOPATHIES.) Poliomyelitis Anterior Acuta Infantium. Poliomyelitis Anterior Acuta Adullorum. Poliomyelitis Acuta. Poliomyelitis Anterior Chronica. Degeneration of the Ganglion Cells of the Anterior Horns of the Spinal Cord and Motor Cells of the Me- dulla Oblongata. (Primary Muscular Disease.) II. Cerebro-spinal Lesions. (PYRAMIDAL TRACT.) . LESIONS OF THE LATERAL COLUMNS. Primary Lateral Sclerosis. Amyotrophic Lateral Sclerosis. Combined Posterior and Lateral Sclerosis. / Compression Myelitis. l Transverse Myelitis. II. LESIONS OF THE CEREBRAL PYRA- MIDAL TRACT AND MOTOR AREA OF CORTEX. r Lesions of Lenticular Nucleus. I Area of Lenticulo-striate Artery. Lesions of Crura and Pons. Lesions in Area of Opto-striate Artery. Lesions in the Area of the Posterior External Optic Artery. f Unilateral Atrophy of the Motor Area of Cortex. Porencephalus. Lesions of Motor Area of Cortex. THE EXTERNAL KINESIONEU ROSES. 173 3. Reflex Central Kinesioneuroses. The disorders which occur in the reflex mechanisms which are situ- ated in the different parts of the nervous system are almost infinitely numerous, but we shall here mention only a few of the more usual dis- orders of the spinal reflexes. The spinal reflexes may be divided into (1) the superficial, and (2) the deep reflexes, while disorders of the reflex mechanisms may declare themselves by way of an excessive reac- tion, constituting (ility to make combined or complicated movements with certainty and precision, and in advanced cases all movements requiring intricate and delicately balanced muscular adjustment become impossible. The motor incoor- dination usually presents itself in tlie most marked manner during locomotion and station, these being respectively named dynamic and static ataxia. These forms of muscular incooi'dination will be more fully described when locomotor ataxia is under consideration. (3) Encephalic Aiiiornatlc Disorders. [a) Reeling is the well-known gait of a di'unken man. It is caused by irregular swaying movements of the trunk, from side to side and from before backwards, requiring the legs to be moved irregularly in various directions in order to maintain their position vertically under the trunk. Staggering is a slighter degree of motor incoordination than reeling, and vertigo is the subjective correlation of this form of motor disorder. (5) OerebeUar rigidity consists of i-igidity of the muscles of the neck, which in aggravated cases extends to those of the back and extremities, so that complete opisthotonos is induced. This form of rigidity is frequently associated with tumor of the middle lobe of the cerebellum. i. COMPULSORY OR FORCED MOVEMENTS— COORDINATE CRAMPS. These movements are best seen in animals after experimental injury to various parts of the medulla, pons, and crura cerebri, but most of THE EXTERNAL K IX ESTON E U ROSES . 183 them are probably caused by injury to one or other of the peduncles of the cerebellum. The usual forms of these movements are, that in which the animal rolls around the longitudinal axis of its OAvn body, that in which it moves round and round in a circle, and that in which it rotates round the transverse axis of the body, tumbling head over heels in a series of somersaults. INIovements of this kind are never so marked in man as in animals, but less degrees of these movements are some- times observed in disease in the neighborhood of the peduncles of the cerebellum. All the automatic disorders just described are caused by the over- throw of the delicate balance of the tonic muscular contractions, which is necessary for the maintenance of complicated adjustments in space. Irritative lesions of the cortex of the cerebellum, which is the organ for regulating these tonic contractions, gives rise to excessive tonic con- tractions of certain muscles, which destructive lesions cause paralysis of them, Avhich, however, is not recognized as a paralysis, because the cerebi-al influence on the muscles is still intact. In other cases the cerebellum itself is healthy, but false intelligence is sent to it owing to disease of the cerebello-afferent conducting paths, and this leads to a loss of the balance of the tonic contractions of the body, or to loss of equilibration, as it is called. k. SYNKINESIS. Under this term are generally included certain involuntary move- ments of paralyzed parts, but we shall also include under it certain motor disorders which occur in muscles aifected with spasm, as w^ell as certain anomalous movements which occur in muscles that in health are associated in their actions Avith those primarily affected. (1) Associated Movements of Paralyzed Parts. In facial paralysis of cerebral origin the muscles of the paralyzed half of the face may occasionally perform the movements necessary to changes of expression in association with those of the opposite side, although in most cases the contrast between the actions of the two sides is rendered all the more evident under changes of expression. In cases of hemiplegia automatic movements may occur in a completely para- lyzed arm. When the patient sneezes, and under the influence of emotional excitement, the paralyzed extremities may be strongly flexed, while the unaffected limbs remain passive. A voluntary movement of the healthy side is often accompanied by a contraction of the corre- sponding muscles on the paralyzed side. 184 GEXEEAL SYMPTOMATOLOGY. (2) Relative Immuniiy of some Muscles from Paralysis, and their Relative Liability to Convulsion. In ordinary cases of severe hemiplegia some muscles are completely paralyzed, while others are little if at all affected. The muscles which are most paralyzed are those of the extremities and the lower muscles of the face, and those which escape are the muscles of the trunk, and the upper muscles of the face. In unilateral convulsions, however, the spasm keeps limited to one-half of the body in the extremities and lower half of the face, while it often extends to both sides in the trunk and upper part of the face. Looking broadly at the muscles which are most liable to be completely paralyzed in hemiplegia, it may be saiIiere, and r', e'r, v', u', d', I', the respective spinal nuclei of the internal rectus, and the e.\- ternal rectus muscles of the eye, the muscles of articulation and vocalization, those of the upper e.xtremity, the dorsal muscles, and those of the lower extremity, all of the left side ; 1', 2', 3', 4', 5', C, fibres of the pyramidal tract, connecting the corte.x of the left h('mis]ihere with r, et; v, a, d, 1, the spinal nuclei of the right side cor- responding to those already enumerated on the left side ; c, e, fihres of the corpus callosum uniting identical regions of the two hemispheres; c', comnn'ssural fibres connecting the spinal nu- cleus of the internal rectus muscle of one eye with that of the external rectus muscle of the opposite eye ; c", those connecting the spinal nuclei of the muscles of vocalization and articulation of tho two sides; c'", those connecting the special nuclei of the muscles of the trunk: c*, those connecting the spinal nuclei of the posterior extremity of one side witli the anterior extremity of the oppo- site side. The arrows indicate the direction of the conduction. right and left sixth nerves {6n and G>i/) : while c' represents the cross- mg of the commissural fibres. The external rectus of one eye and the mternal of the other eye acting simultaneously rotate both eves so as to direct the axes of vision to lateral objects. When the object is placed to the right it is manifest that the right eye is in a better posi- THE EXTKRNAL KINESIONE Ul? OSES 187 tion than the left to catch the first glimpse of it, hence the external rectus, Avhich rotates the right eye outwards, takes the lead in the action. But the internal rectus of the opposite side rotates at the same time the left eye inwards : and to effect this movement it will be a clear gain of time, as well as economy of force, if it were to receive its impulses to action through the short commissural fibres which connect the two nuclei, and not from the cortex of the cerebrum of the opposite side. When, therefore, the eyes are directed by a voluntary effort to the right, the impulse to action may be supposed to come from the cortex of the brain (C) on the opposite side, to pass out through the fibres (2') of the pyramidal tract which connect the cortex with the nucleus of the sixth nerve {er'), and then to pass on through the commissural fibres (c') to the part of the nucleus (r) of the opposite third nerve concerned in the action. According to this statement, therefore, in directing the eyes laterally, say to the right, both the right external rectus and the left internal rectus receive the impulse to action from the cortex of the left hemisphere, the impulses of the nucleus of the third nerve being received through the commissural fibres which con- nect it with the nucleus of the sixth nerve of the opposite side. So far, Ave have only spoken of the two recti muscles; but when these muscles are contracting so that the eyes are directed laterally, the muscles which rotate the head also become contracted in such a way that the head is turned in the same direction as the eyes, this movement being frequently observed when a man looks over his shoulder. Rota- tion of the head, say to the right, is produced mainly by contraction of the right inferior oblique muscle of the neck, although the left sterno- mastoid, and probably other muscles, cooperate in the movement, and these muscles also receive their voluntary impulses to action through commissural fibres which connect their nerve nuclei with the nucleus of the sixth nerve of the right side. According to this supposition, when a strong impulse is sent from the left cortex (C) of the brain through the fibres ('2') which connect it with the nucleus {er) of the sixth nerve of the opposite side, these impulses will also pass through commissural fibres to the nuclei of the nerves which supply the internal rectus and sterno-cleido-mastoid muscles of the opposite side, and of the inferior oblique muscle of the neck of the same side ; and the eyes and head will consequently be strongly rotated to the right, and away from the hemisphere from which the impulses originated. But this lateral devi- ation or conjugate deviation of the eyes, as it is called, occurs fre([uently in disease, and it is then associated with rotation of the head and neck to the same side as the eyes are directed. This position of the eyes and head is almost a constant accompaniment of convulsions of cereljral 188 GENERAL SYMPTOMATOLOGY. orio-in, and, when the convulsions are unilateral and due to disease of the cortex of one hemisphere, the rotation always takes place towards the convulsed side and away from the seat of the lesion. Unilateral convulsions are often associated with a certain degree of hemiplegia, the convulsions being then limited to the paralyzed side ; and when, under these circumstances, conjugate deviation of the eyes occurs, the rotation is always towards the paralyzed side. This, then, constitutes spasuiodic lateral deviation of the head and eyes. But Graux has drawn attention to the fact that this lateral deviation is often of para- lytic origin. Let us now suppose that the fibres (2') which connect the left cortex (C) and the right nucleus of the sixth (er) are suddenly interrupted, the cerebral impulses to the nucleus are arrested, the ex- ternal rectus of the right eye becomes paralyzed, and that eye is rotated to the left. But the impulses through the commissural fibres which connect the nucleus of the right sixth, and those of the left internal rectus, and of the rotators of the head to the left must also be arrested, so that the latter muscles likewise become paralyzed ; hence the left eye and the head become, rotated to the left, the rotation now taking- place awai/ from the paralyzed side and towards the hemisphere of the brain in which the disease is situated. The rotation of the eyes in this direction has been facetiously described as an attempt on the part of the patient to inspect the cerebral lesion which is the cause of the paralysis. The rotation of the eyes, head, and neck is not now due to spasm of the muscles engaged in producing the action, but to paralysis of their antagonists. This symptom is usually associated with all sudden and severe attacks of hemiplegia ; it is generally absent in the slighter forms of the attack, and in all cases in which the paralysis is more or less gradual in its onset. The ])henomenon is also, as a rule, a very transitory symptom in hemiplegia, and usually disappears in from four days to a week. The rotation of the head generally disap- pears first, and then the deviation of the eyes improves; but it not unfrequently happens that a temporary s(iuint may be observed during the progress of the rotation of the eyes towards recovery. The reason of the temporary character of the paralytic form of con- jugate deviation of the eyes and rotation of the head and neck — say towards the right— appears to be that although the nucleus of the left third {r') usually receives its impulses to action through the commis- sural fibres which connect it with the nucleus of the right sixth nerve (er), and consequently from the cortex of the left hemisphere, yet channels of communication (1) still exist between the nucleus of the left third and the cortex of the right liemisphere. There is no congenital defi- ciency of the channels which connect the cortex of the ri^^ht hemi- THE EXTERNAL KIN ESI OX EU ICOSES . 189 sphere and the nucleus of the tliird nerve of the opposite side, nor indeed of the oblique commissural fibres -which connect the latter with the nucleus of the right sixth nerve ; and now that the more usual channels are interrupted by disease, impulses begin to pass through the k'ss used channels. In a few days, then, the channel (1) between the right cortex and the nucleus of the left third nerve becomes patent, and some days later the commissural fibres (c) between the two nuclei liecome so for open as to convey impulses from the nucleus of the left third to that of the right sixth, so that the paralysis of the muscles supplied l)y these nerves disappears. A destroying lesion in the pons situated above the nucleus of origin of the sixth nerve, but below the upper crossing of the fibres of the pyramidal tract, causes a conjugate deviation, Avhich is directed away from the side of the lesion and towards the paralyzed limbs. It has also been shown by Graux that whereas disease of one of the sixth nerves produces an internal squint of the eye on the side of the lesion, and no affection of the other eye, disease of the nucleus of origin of one of the sixth nerves produces a conjugate deviation of the eyes, the external rectus on the side of the lesion and the internal on the opposite side being thus more or less ' ])aralyzed. But the internal rectus is not completely paralyzed, although it does not act when the eye has to be directed to lateral objects, it contracts quite well in association with the internal rectus of the oppo- site eye when the eyes are converged on a near object in front. These facts prove that the internal rectus muscle is innervated by fibres issuing from, or at least passing near the nucleus of origin of the sixth nerve of the opposite side, as Avell as by fibres from the third nerve of the same side. As we have seen, conjugate deviation of the eyes is, as a rule, a transitory symptom in hemiplegia, but if a lesion in the pons • interrupts the commissural fibres (c) so as to prevent impulses passing from one nucleus to another, a second lesion situated in any posi- tion which will interrupt the fibres of the pyramidal tract will then produce a paralytic conjugate deviation of the head and eyes which remains permanent. (4) Secondary Deviation of the Sound Eye. In paralysis of one of the ocular muscles, say of the external rectus of the right side, the eye is of course subject to internal s(piint. Now, if durino- recovery from this condition, when the conduction through the sixth nerve (6») is still delayed, the eye of the sound side be closed and the patient be directed to look at an object with his right eye in such a way as to strain the external rectus nuiscle, this strain is 190 GENERAL SYMPTOMATOLOGY. accompanied by a strong voluntary effort, but owing to the diminished conductivity of the nerve only a relatively small amount of the volun- tary impulses will pass to the muscle. But the impulses generated by the strong voluntary effort will pass through the commissural fibres {(■') to the nucleus of the left third nerve {r') in undiminished degree, so that the internal rectus of the left eye becomes strongly contracted. The energetic contraction of the internal rectus of the left eye induces a secondary squint in it, the extent of Avhich is much in excess of that of the squint of the paralyzed side. But although this secondary deviation is more apparent in the case of paralysis of the ocular than in paralysis of other muscles, yet essentially the same phenomenon occurs in the extremities. If the common extensor muscle of the toes is partially paralyzed, a voluntary effort to extend the toes is followed by flexion of them. A simple movement like flexion at the elbow-joint is not caused by contraction of the flexors only, but by the predominance of their contractions over the contraction of the extensors simulta- neously induced. During recovery from an attack of hemiplegia it often happens that when the patient makes an effort to flex the forearm the flexor muscles may be observed to contract, yet either no movement or movement in the opposite direction occurs, because the balance of the innervation to the antogonistic muscles is equal to, or the innerva- tion to the extensors is in excess of, that to the flexors. (5) Disorders of the Associated Movements of the Extremities. We have seen that the movements of the limbs, and especially of the hand of one side, are largely independent of those of the other, and consequently that the spinal nuclei of the nerves which supply the limbs are not intimately connected by transverse commissural fibres. But in walking, the movement of the right leg is always associated with swinging of the left arm; and, conversely, that of the left leg with swinging of the right arm. It may be inferred, therefore, that the nuclei of the nerves of the upper [a a') and lower extremities (/ V) are connected by oblique and crossed commissural fibres. In man the movements of the leg of one side are not very intimately associated with that of the arm of the opposite side, hence the commissural fibres, which connect their respective nerve nuclei, are represented by dotted lines (e" ). In quadrupeds, however, the crossed association between the movements of the anterior and posterior extremities of opposite sides IS much more intimate than in man, and consequently the oblique commissural fibres are patent in a corresponding degree. Let us now suppose that the fibres (4' and (J') which connect the coitex (C) of the left hemisphere with the spinal nuclei {a, I) of the THE EXTEENAL KIN ESIONEU ROSES . 191 light extremities are ruptured. Rupture of these fibres would produce hemipk-gia in man ; but in the dog only a certain amount of paresis results, inasmuch as the right hind limb receives impulses through the open commissural fibres which connect the spinal nuclei of its nerves with the nuclei of the nerves of the left anterior limb. The right anterior limb likewise becomes innervated through the commissural fibres which connect the nuclei of origin of its nerves with those of the nerves of the left posterior extremity. All the limbs of the dog, therefore, become innervated from one hemisphere when the other hemisphere is injured, so that, although disease of one hemisphere causes a certain amount of paresis, no true paralysis or hemiplegia results as in the case of man. This condition has often been induced by experimental lesions of one of the hemisplieres in the dog, and it is always associated with conjugate deviation of the head and eyes, show- ing that both phenomena are induced by disease of the same mechanism. But although the dog does not manifest complete paralysis of the mus- cles of the side opposite the lesion — say the right side, the lesion being in the left hemisphere — yet, on standing, a slight degree of pressure on the left side pushes the animal over to the right, the vertebral column is arched with the convexity towards the right, showing a predominance of the action of the left erector-spin^ over their antagonists, and the eyes and head are rotated to the left, a position whicli indicates paresis of the muscles which produce rotation of them to the right. Under these circumstances, Avhen the dog endeavors to advance he begins to move round his tail, a movement which has been called " mouvement de manege^' and Avhich is the equivalent of hemiplegia in man. It is, therefore, probable that some of the compulsory movements described as automatic kinesioneuroses really belong to the synkineses, as at present defined. (6) Disorders of the Associated Movements of Articulation. But when the muscles which are bilaterally associated in their action are small, and when minor nervous discharges only are re(i[uisite to throw them into action, the connection of the muscles of the two sides with one hemisphere may be brought into such habitual use that the connection with the other hemisphere, although still existing, is held practically in abeyance. The muscles concerned in executing the movements of articulation, for instance, are bilaterally associated ; the necessary adjustments demand great delicacy of execution, but no great muscular exertion ; the muscles engaged in executing the most delicate 192 GENEEAL SYMPTOMATOLOGY. of these adjustments are small, and consequently these muscles fulfil all the conditions just mentioned. It is now a matter of almost daily observation that the muscular adjustments concerned in articulate speech are regulated from the left hemis[)here ; but it by no means follows that the regulation of all the functions performed by these muscles is similarly restricted. The con- tractions of the laryngeal muscles concerned in vocalization, for instance, are not necessarily interfered with, because the delicate adjustments required in articulate speech are abolished ; hence complete loss of the power of articulate speech is perfectly compatible with entire absence of voluntary paralysis of any of the muscles engaged in articulation. It is not the power of producing voluntary contractions of these mus- cles which is lost, but the power of producing highly complex coml)i- nations of these contractions. If we suppose that v and v' are the spinal nuclei of the nerves {v n, v n') which supply the muscles of articulation, the two nuclei are practically fused into one by transverse commissural fibres {c") ; and consequently impulses which start from the left cortex (C), and pass through the fibres (3') to the spinal nucleus {v) of the right side, readily reach the left nucleus (y') through the commissural fibres [c"). But as the muscles concerned in articu- lation act always bilaterally and symmetrically, the channels of com- munication between the spinal nuclei of their nerves and the cortex of one hemisphere are brought into habitual use ; while tlie channels of communication between these nuclei and the opposite hemisphere become partially obliterated from disuse, and prol)ably not thoroughly developed from the first. The channels of comnmnication between the right cortex (C) and the nuclei v and v', for instance, are represented by the dotted line (3 3), and the commissural fibres which convey impulses from the left to the right nucleus by the dotted line {c"), in order to indicate that these channels are only partially open. De- struction of the communication (3') between the left cortex (C) and the right nucleus {v) is followed by loss of articulate speech, a condition Avhich is called aphasia. If the lesion destroy the portion of the cortex of the left liemisphere —the posterior part of the third frontal convolution— from which the fibres of communication spring, this condition is permanent, except perhaps in young people, in whom the corresponding part of the right hemisphere becomes educated and develoi)ed for the purpose. But if the lesion involve only the channel of communication (3') between the left cortex and the right nucleus, the loss of speech is only temporary. The corpus callosum consists of fibres {c c) which connect symmetrical parts of the two hemispheres; and the portion of it which connects THE EXTERNAL KINESIONEUROSES. 193 the third frontal convolution of the two sides is represented in Fig. 72 by the dotted line to show that, although the connection exists it is l)artially closed through disuse. When, however, the communication through (3') is interrupted, impulses generated in the third left frontal convolution make their way through the fibres of the corpus callosum to the corresponding part of the right hemisphere, and after a time through the dotted line (8) which connects the latter with the left nucleus, and, after another interval, through the partially open com- missural fibres Avhicli connect the left (v) with the right nucleus (v'). so that the power of speech is gradually reac(|uired. A lesion, however, which destroys both the channel of communication (3') between the third left frontal convolution and the spinal nuclei, and the fibres of the corpus callosum [a r, dotted line) connecting tlie right and left third frontal convolutions, Avill influence speech as powerfully and perma- nently as disease of the gray substance of the third left frontal convo- lution itself. Such a lesion effectually cuts off the third left frontal convolution, in which the higher mechanism which regulates the mus- cular adjustments concerned in articulation is organized, from the spinal nuclei ; and the only means by which speech can be then restored is the organization of a new mechanism in the corresponding part of the right hemisphere, a method which must always be slow, and which can onh^ take place, at least to any considerable extent, in the plastic tissues of young people. 13 CHAPTER YII. GENERAL SYMPTOMATOLOGY [contmued). II. The Visceral Kinesioneuroses. The motor affections of internal organs present many peculiarities in comparison with those of the organs of external relation. These peculiarities depend in great part upon the fact that the muscular apparatus of" the internal organs is formed of unstriated muscular tissue, which differs from the striated muscle in its mode of contraction, and in several other respects. An unstriated muscular fibre does not respond to mechanical and electrical stimuli by a prompt contraction of short duration, but a long latent period precedes the contraction, which itself lasts for a considerable time, while relaxation takes place only in a slow and gradual manner. Another peculiarity of the contractions of unstriated muscles is the rhythmic and automatic manner in which they occur ; these characteristics being well exemplified by the peri- staltic action of the intestines and ureters. It is very ])robable that these movements depend upon the presence of local ganglia on the walls of the organs, although there are not wanting facts to show that the power of undergoing such contractions is an inherent property of the unstriated muscular fibres themselves. The functions of these intramural ganglia are regulated by means of accelerating and retard- ing nerve fibres from centres situated in the cerebi'O-spinal system, so that arrest of the contractions of unstriated muscles may be caused by a destructive lesion of the accelerator or an irritative lesion of the in- hibitory fibres, while spasm may be caused by an irritative lesion of accelerator fibres or a destructive lesion of inhil)itory fibres. The movements of the internal organs are regulated chiefly by the ganglia and plexuses of the sympathetic system, but these are so inex- tricably connected with the cerebro-spinal system that it is impossible to draw any line of demarcation between the two nervous mechanisms. The sympathetic system of nerves consists of a vertebral and pre- vertebral portion. The vertebral portion is composed of a series of ganglia, united by a longitudinal cord (Fig. 78, I C to C) which de- scends along each side of the vertebral cofumn from the head to the coccyx. The prevertebral portion consists of the numerous ganglia THE VISCEEAL KINESIOXEUEOSES. 195 Superior Cervical Ganglion of the Sympathetic: its connections andbrakciies. (Reduced from Flower.) IC to IVC, Branches of communication to four upper cervical nerves PS, " " petrosal ganglion. Vr, " " ganglion of root of pneumogastric. V', " " ganglion of trunk of pneumogastric. H, " " hypoglossal nerve. CP, Carotid plexus. C'P, Cavernous plexus. CA, Branches accompanying internal carotid artery. OG, " to ophthalmic ganglion. X96 GENEEAL SYMPTOMATOLOGY. Ih, To tympanii; branch of glosso-pbaryngeal. g| 3, to third nerve. - 4, to fovirth nerve. 5, to fifth nerve. e, to sixth nerve. ^ V, Vidian nerve to spheno-palatine ganglion. '' S p, Large superficial petrosal from facial nerve. E.\0, Accompanying branches of external carotid artery. PP Pharyngeal plexus, formed by union with branches of vagus and glosso-pbaryngeal nerves. SG, Superior cardiac nerve. The Middle Ceritical, or Thyroid Ganglion. IVC to VIC, Branches of communication with fourth, fifth, and sixth cervical nerves. IT, Inferior thyroid branches. MC, Middle cardiac nerve. RL, To recurrent laryngeal. The Inferior Cervical Ganglion. VIIC to Vine, Branches of communication with seventh and eighth cervical nerves. IC, Inferior cardiac nerve. CP, Cardiac plexus. GW, Ganglion of Wrisberg. LCP, Posterior, or left coronary plexus. KCP, Anterior, or right coronary plexus. CRL, Cardiac branches from pneumogastric or recurrent laryngeal nerves. APP, To right anterior pulmonai-y plexus. LPP, To left anterior pulmonary plexus. ID to IID, Branches of communication from the first to the twelfth doi-sal nerves. a, a, To aorta, vertebrae, cesophagus, and posterior pulmonary plexus. GSN, Great splanchnic nerve. SSN, Small splanchnic nerve. SSN', Smallest splanchnic nerve. D, Diaphragm. PN, Phrenic nerve. SP, Epigastric, or solar plexus. CLP, ('celiac plexus. Cs, Cystic plexus. GSD, Gastro-duodenal plexus. C s P, Gastric or coronary plexus. Vy, Pyloric plexus. SpP, Splenic plexus. LGsE, Left gastro-eplploic plexus. Po-, Pancreatic plexus, HjjP, Hepatic plexus. V", Branches from pneumogastric. DmP, Diaphragmatic plexus. SG, Semilunar ganglion. SK«P, Suprarenal plexus. BkP, Renal plexus. SpV, Spermatic plexus. SMP, Superior mesenteric plexus. Mce, Middle colic. Kce, Right colic. Ice, Ileo-colic. AP, Aortic plexus. IMP, Inferior mesenteric plexus. LCI, Left colic plexus. Sz, Sigmoid plexus. I SHni, Superior hemorrhoidal plexus. I IL to VL, Branches of communication with the five lumbar nerves. IS to VS, five sacral nerves. IHP, Pelvic, or inferior hypogastric plexus, giving branches to all the pelvic visceni. ' ' coccygeal ner\'e. HP, Hypogastric plexus. THE VISCERAL K INESIONEUROSES. 197 and plexuses of the head, chest, abdomen, and pelvis. The cerebro- si)inal nerves communicate with the cord of the sympathetic at their exit from the cranium and vertebral canal. The fourth and sixth cranial nerves communicate with the sympathetic in the cavernous sinus tlie olfactory in the nose, and the auditory in the meatus auditorius internus. The sympathetic branches of distribution accompany the arteries, so that all the organs of the body are supplied by sympathetic nerves. 1. Disorders of the Nervous Mechanism of the Iris and other Associated Mechanisms. The nervous mechanism of the iris (Fig. 74) consists of a (1) con- tractor centre in the crus cerebri (C), which forms part of the nucleus A A, psychical impression ; B, centrum optici ; C, oculo-motor centre ; D, dilator centre (spinal) ; E, iris ; G, optic nerve ; H, oculo-motor (sphincter) ; I, sympathetic (dilator) ; K,*L, anterior roots ; M N 0, posterior roots; /^, seat of lesion causing reflex pupillary immobility ; *, probable seat of lesion causing myosis. (After Erb.) of the third nerve ; (2) a cortical contractor centre (A), situated prob- ably in the angular gyrus ; (3) a dilator centre in the medulla (D) ; and (4) a cortical dilator centre (A), situated probably in the posterior part of the first frontal- convolution. The cortical centres are connected with the contractor and dilator spinal centres by centrifugal fibres which descend in the pyramidal tract ; the spinal contractor centre is con- 198 GENERAL SYMPTOMATOLOGY. nected with the sphincter of the iris (E) by efferent fibres (H) which pass in the third nerve ; and the dilator nucleus with the dilator muscle by means of efferent fibres which descend in the cervical region of the cord, emero-e along with the anterior roots of the eighth cervical (K) and first dorsal (L) nerves, ascend in the cervical sympathetic, and ultimately find their way to the dilator fibres through the cavernous plexus, the lenticular nucleus, and the ciliary nerves. The contractor nucleus is connected with the surface by afferent fibres which pass from the retina (F) in the optic nerves and tracts (G) to the corpora quadri- gemina (B), and then bend down to join the contractor nucleus in the floor of the aqueduct of Sylvius. The afferent and efferent fibres of the contractor nucleus form a reflex loop, so that when light falls on the back of the eye the iris contracts. The dilator nucleus appears to be connected with the surfiice of the body generally by afferent fibres (M N 0), so that strong irritation of any part of the surface of the body causes the iris to dilate. It will be seen that only part of this mechanism belongs to the sympathetic system, but it will conduce to clearness if all the disorders of the })U])ils are considered in this place. The cervical sympatlietic also contains vaso-motor fibres for the corresponding half of the head, and trophic and secretory fibres for the salivary glands. The orbital muscles of iSIiiller are also innervated from the cervical sympathetic. Irritation of the fibres supplying these muscles causes the eyeball to protrude (exophthalmos), and the jialpe- bral aperture is consequently widened ; while paralysis of them allows the eyeball to fall back into the orbit, and the palpel)ral aperture is then narrowed. The eyeball appears also to undergo trojihic change, which increases the intraocular pressure and renders the cornea more convex in irritation of the fibres, and diminishes the intraocular pres- sure and renders the cornea flatter in paralysis of the fibres. a. Disorders of the Movements of the Iris. The disorders of the movements of the iris may be divided into the following varieties, namely, (1) contraction of tlie pupil, or myosis ; (2) dilatation of the pupil, or mydriasis ; (3) immobility of the pupil with normal size ; (4) clonic spasm of the muscles of the iris ; and (5) reflex disorders of the pupil. (1) Myosis.— Three forms of myosis may be distinguished, namely, (a) spastic or spasmodic myosis caused by spasm of the sphincter ; {h) paralytic myosis, caused by paralysis of the dilator fibres ; and (c) combined spasmodic and paralytic myosis, caused bv simultaneous spasm of the sphincter and paralysis of the dilator fibres. In the first THE VISCERAL KINESIONEUROSES . 199 two of these varieties the i)upil is in a medium degree of contraction and movable, and consequently they may be named the medium or labile mijoses. In the last of the three the pupil is in the hio-hest degree of contraction and immovable, and conse(|uently it may be named maximum or stabile mi/osis. (a) Spastic myosis, if in high degree, prevents the pupil contracting to light or during efforts at accommodation. The pupil does not dilate by shading the eyes, but a moderate degree of dilatation is caused bv all excitants of the dilator centres or fibres, such as a strong sensory impression or emotional disturbance. A minimum dilatation is produced by mydriatics, and a maximum contraction by myotics. {b) Paralytie nii/osis does not prevent the pupil contracting to the stimulus of light or during efforts at accommodation, but dilatation does not occur in irritation of the dilator centres or fibres. A medium degree of dilatation is produced by mydriatics and a maximum contrac- tion by myotics. The pupil is more contracted, as a rule, in spas- modic than in paralytic myosis. (c) Combined spastic and paralytic myosis causes a maximum de- gree of contraction of the pupil, which is also completely immovable to the stimulus of light and accommodation, as well as to those which act on the dilator centres and fibres. Mydriatics cause a medium degree of dilatation, but myotics have no effect on the size of the pupil. (2) Mydriasis. — Three forms of mydriasis may^ also be distinguished, namely, {a) spastic or spasmodic mydriasis, (b) paralytie mydriasis, (e) combined spasmodic and paralytic mydriasis. In the spastic and paralytic form the pupil is in a medium degree of dilatation, and movable to certain stimuli, and conse(piently they may be named medium or labile mydriasis ; while in the combined form it is in a con- dition of maximum dilatation and immovable, and consequently it may be called maximum or stabile mydriasis. (a) Spasinodic mydriasis is characterized by a medium degree of dilatation of the pupil, which contracts slightly to light and during efforts at acconnnodation, but does not dilate on irritation of the dilator centre either through sensory nerves or psychical impressions. The pupil is difficult to contract by myotics, but a maximum dilatation is readily produced by mydriatics. {b) Paralytic mydriasis is characterized by a medium degree of dila- tation of the pupil, which fails to contract to the stimulus of light or during efforts at accommodation, but dilates further on sensoi-y or psychical irritation of the dilator spinal centre. A maximum dilatation is readily produced by mydriatics, but a medium contraction alone is produced by myotics. 200 GENEllAL SYMPTOMATOLOGY. ((•) Oomhined spasmodic and 'paralytic mydriasis is cliaructerized by the pupil being in a maxinium degree of dilatation, and eorai)letely reactionle.ss to all kinds of stimuli. It is not possible to ol)tain a further dilatation of the pupil by mydriatics, but a medium degree of contraction is produced by myotics. (8) Complete immohllity of the pupil with normal size is caused by paralysis of both the dilator and contractor muscles of the iris. When the muscles of the iris are alone affected the condition is named () spinal, and (/•) cerebral lesions : while special mention will be made {d) of the vaso- motor disorders of the viscera. a. Peripheral Ancjioneuroses Reflex vascular disorders may be produced by lesions of the afferent fibres which pass from the vessels to the local ganglia, or of afferent fibres which pass to the ganglia situated higher up. These reflex dis- orders may consist of spasm or dilatation, although it is not known under what conditions the one or the other state is caused. Dilatation of the vessels of the conjunctiva, for example, is caused by neuralgia of the first division of the trigeminus, but it is not known whether the action is reflex or direct, or whether the vascular dilatation is caused by paralysis of vaso-motor constrictor or irritation of vaso-dilator fibres. Division of large nerve trunks is followed by redness and increased temperature of the parts supplied by the injured nerve, which is caused by paralysis of the vaso-constrictor nerves. But degeneration of the nerve fibres induces trophic changes in the affected extremity, which causes the material exchanges to be diminished and the circulation to be less active, and consequently less heat is generated, while more is radiated owing to the dilatation of the vessels, and the temperature falls below the normal. Paralysis of the vaso-motor nerves of an extremity occurs sometimes in the absence of any other symptom of nervous disease. b. Spinal Anoioneuroses. Lesions of the vaso-motor centres in the medulla and spinal cord, or of their respective conducting paths, may increase or diminish the arterial tone either locally or generally. Injuries and diseases of the spmal cord which cause paraplegia are generally associated by a pri- THE VASCULAR KINESIONEUROSES. 219 maiy increase of temperature of the paralyzed limbs. In hemipara- plegia of spinal origin there is a primary increase of temperature in the paralyzed as compared with the non-paralyzed limb. Injuries of the cervical portion of the cord near the medulla oblon- gata cause a remarkable elevation of the temperature of the body, and in these cases the temperature may continue to rise after the injurv. and may even increase considerably after death. This remarkable rise of temperature probably depends upon sudden paralysis of the vaso- motor system, or upon interference with the action of a heat-regulating centre in the medulla oblongata. In locomotor ataxia, again, which is a disease of the afferent or sensory portion of the spinal cord, the lower extremities are often cold from vascular spasm, and in some cases of this disease a local alteration of the vessels occurs Avhich is so remark- able as to require special mention. Tabetic JEcchi/Dioscs. — In the course of locomotor ataxia, patches of discolored skin are found scattered irregularly over the lower extremi- ties and lower part of the trunk. These patches are at first of a bright red color, but soon become purple, and pass, like ordinary ecchymoses, through various shades of brown, green, and yellow, until they finally fade from the circumference to the centre, and disappear in from four to six days from the commencement. These ecchymoses appear suddenly towards the termination of severe paroxysms of lancinating pains and gastric crises. They are irregularly circular in form, and vary in size from a few lines to more than an inch in diameter. Several of these patches are found at the same time, as many as three or four of them being observed on each lower extremity. The local asphyxia of Renaud belongs probably to the angioneuroses, but, as it often terminates in gangrene, its description will be found amongst the trophoneuroses. c. Cerebral Angioneuroses. Vaso-motor disorders are daily observed under the influence of various emotions, the most familiar of these being the blush of shame and the pallor of fear. Fainting is associated with pallor of the sur- face, and alternatincr conditions of pallor and redness are often observed in various neuroses, such as hysteria and epilepsy. At other times the vascular alteration, instead of being diffused, occurs in patches — what has been observed under the name of cerebral maculae. Taches cerebrales consist of red blotches and mottlings on the chest or abdomen of epileptics, and those suffering from Graves's disease and other neuroses. When the affected portion of skin is rubbed, or, ni strongly marked cases, is merely touched by the finger, the surface soon 220 GENERAL SYMPTOMATOLOGY. becomes suffused ^vitll bright red marks, which spread to some distance around the point touched, and persist for several minutes. d. Visceral Axgioneuroses. The vaso-motor nerves of the thoracic viscera are derived from the inferior cervical and superior tlioracic ganglia, and from the spinal cord bv communicating branches from the third to the seventh dorsal vertebrge. The vaso-motor nerves of the abdominal viscera exist chiefly in the splanchnic nerves. Section of the splanchnic nerves occasions a great diminution of the arterial pressure from dilatation of the vessels and engorgement of the abdominal viscera. Irritation of the distal end causes contraction of the vessels and conseciuent eleva- tion of the blood pressure. A part of the vaso-motor nerves of the abdominal viscera probably passes in the vagus. Experimental in- jury of the lumbar portion of the spinal cord in animals has been found to cause congestion and even extravasation of blood in the suprarenal capsules, and hemorrhagic foci have been found in these organs in cases of acute myelitis. Crushing of the pons and basal ganglia in animals has l^een found to cause congestion and ecchy- moses in the lungs, pleura, kidneys, and nmcous membrane of the stomach and bowels, and Eulenburg found intestinal hemorrhage after bruising the cortex of the occipital lobe of the brain. Congestion and extravasations of blood in the internal organs are not uncom- mon as complications of cerebral apoplexy. The various menstrual disorders which are so frequently associated with emotional disturb- ances are no doubt the result <)f functional disorders of the vaso-motor nerves, and the vicarious hemorrhages of the stomach, intestines, lungs, and other organs probably also depend iijjon disorder of vaso-motor innervation. Both quantitative and (pialitative anomalies in the con- dition of the urine probably de])end upon disorder of the vaso-motor nerves of the kidneys. Bernard found that injury of the upper part of the floor of the fourth ventricle causes polyuria and albuminuria, while injury of the lower part of the floor of the fourth ventricle causes temporary glycosuria. Injuries of the spinal cord, in the cervi- cal and thoracic ganglia, or of the large nerve-trunks, such as the sciatic nerve, are also followed by glycosuria. If the pneumogastric nerve is divided in the neck, stimulation of the upper end is followed by dilatation of the vessels of the liver, and the appearance of sugar in the urine. The most reasonable explanation of these phenomena is that vaso-motor paralysis of the hepatic artery causes engorgement of the hepatic vessels, which gives rise to an increased production of THE VASCULAR KUSTESIONEUROSES. 221 sugjir. Certain forms of enlargement of the liver and spleen are l^robably caused by paralysis of vaso-motor nerves. Section of tlie cfterent fi))res of the semilunar and splenic plexuses in animals causes enlargement of the spleen, while ii-ritation of these fibres reduces its size and renders the organ paler. Extirpation of the coeliac and mesenteric plexuses causes, besides other phenomena, congestion and enlargement of the liver, and it is probable that the congestion of this organ which takes place during attacks of migraine is of vaso-motor oriirin. CHAPTEK YIII. GENERAL TREATMENT. Nervous diseases must be treated according to the same general principles as all other diseases, and it is therefore unnecessary to entei- upon a detailed description of treatment in this place. The treatment of nervous diseases may be divided into that which is directed : (1) to prevent disease ; (2) to remove the exciting cause of the disease ; (3) to remove the anatomical cause ; and (4) to allay or remove serious symptoms. 1. PROPHYLACTIC TREATMENT. Prophylactic treatment consists of a special application of hygienic rules to the cases of those who manifest inherited or acquired proclivi- ties to diseases of the nervous system. The children of parents who have suffered from severe nervous diseases, like hysteria, epilepsy, or neuralgia, ought to be specially guarded against being subjected to severe mental strain and emotional excitement in youth, and especially during the period of sexual development. The children of such parents are generally quick in their perceptive ficulties and are possessed even of great intellectual activity, and they ought not to be allowed to enter upon competitive examinations at schools except under the strictest precautions. Parents and teachers ought to pay great attention to such symptoms as headache, sleeplessness, horrible dreams and night starl- ings, and loss of flesh and appetite, Avhich are the more usual symptoms of an overstrained nervous system. Of these symptoms, sleeplessness is probably the most important as a danger signal, inasmuch as, on the one hand, it is generally caused, especially in the absence of pain, by exhaustion of the nervous system, and, on the other hand, it becomes a powerful cause of further exhaustion, because the nervous energies used up during the day fail to be restored at night. Plenty of muscular exercise, so long as it is thoroughly enjoyed and stops short of inducing fatigue, is the most powerful means we possess of fortifying the nervous system in young people. Those who inherit a predisposition to nervous disease also require an abundance of plain and nourishing diet, and a due exposure to sunlight and fresh air. REMOVAL OF THE ANATOMICAL CAUSE. 228 2. REMOVAL OF THE EXCITING CAUSE. When a disease of the nervous system has been induced by unfavor- able circumstances of climate, exposure to variations of temperature, or excessive fatigue, these conditions must, if possible, be corrected • and Avhen the disease has been caused by wounds, contusions, or com- pression of nervous tissues, these causes must be removed, and the damage done to the tissues repaired as much as possible by suro-ical interference. If the disease is caused by a morbid poison like syphilis, malaria, gout, rheumatism, or the metallic poisons, the treatment must be directed to remove these poisons from the system or to neutralize their action. 3. REMOVAL OF THE ANATOMICAL CAUSE. The nutrition of diseased nervous tissues may be favorably influenced by agents which act directly on the nervous tissues themselves, the connective tissues which surround the nervous tissues, the vaso-motor nerves and centres of the bloodvessels themselves, and the blood. The agents by which nutrition can be influenced may be divided into (a) internal and [b) external remedies. (a) Internal Remedies. Internal remedies produce their action after gaining admission into the circulation either by being absorbed through the mucous membranes, skin, or subcutaneous tissues after injection, or by direct injection into a vein. The following are some of the remedies of this class : Strychnia and the preparations of nux vomica increase the irritability of the gray substance of the sj^inal cord and diminish its specific resistance, and they are usefully administered when the irritability is depressed. Strychnia is a powerful remedy in atonic dyspepsia, constipation with flatulence, paralysis of the sphincters, nocturnal incontinence of urine, and sexual debility ; but does not possess much value in the treatment of organic diseases of the spinal cord, being valueless in chronic spinal affections and positively injurious in all acute organic aff'ections. Conium depresses the irritability of the spinal cord and of the motor nerves, and its use has been recommended by Dr. Crichton Browne in acute mania, and it has likewise been found useful in tetanus. CaJahar bean lessens and ultimately destroys the irritability of the gray sub- stance of the spinal cord, causing anaesthesia, loss of reflex excitability, and paralysis. It has been found useful in tetanus and in hemicrania. 224. GENERAL TEEATMENT. Its alkaloid, physostig)>ia, iucreases the irritability of the terminal fibres of the vagus, and kills by paralyzing the respiration. Belladonna and its alkaloTd, atrojnne, increase the irritability of the gray substance of the spinal cord, and stimulate in a special manner the respiratory and vaso-motor centres, the cardiac acceleratory nerve or its centre, and the pupillary fibres of the sympathetic to the eyes. It paralyzes the motor nerves, first aifecting those of the trunk, the terminations of the vagi both in the heart and lungs, the terminations of the secretory nerves of the salivary glands and of the sweat glands, the terminations of the inhibitorv fibres of the splanchnics, and the terminations of the nerves supplying the iris. In large doses it depi-esses the functions of the afferent nerves. This drug has been found useful in cliecking profuse sweating, especially the night sweats of phthisis, and the secretion of milk. It is also useful in habitual constipation, Avhooping cough, incontinence of urine, and nocturnal emissions; and its use has been recommended bv Brown-Sequard in chronic organic spinal diseases on the grounds that it contracts the arterioles of the cord. It is also useful in allaying pain, but is inferior to opium. JEr(/ot is given in chronic spinal affections, being supposed to have the power of contract- intr the arterioles. Opium lessens the irritability of the sensory con- ducting paths and of the perceptive centres. Small doses first increase the irritability, but the primary increase is soon followed by a secondary stage of depression, and if a large dose be administered the first stage of increased irritability is so transitory that it may be overlooked. Opium may be administered in small doses so as to obtain tlie primary or stimulant action, and given in this way it is foun?mia, arterial degeneration, wounds, cicatrices, and diseases of neighborini: tissues exercise the same influence in neuralgia of the fifth as in the neuralgine of other nerve territories. SymjJtoniH. — Facial neuralgia consists of attacks of pain in the area of distribution of the fifth nerve (Fig. 77) or of one of its branches, which are apt to recur on the slightest exposure to the exciting cause, or even in the absence of such cause. Each attack is made up of recurring paroxysms of severe pain, separated by intervals of com- parative but not entire freedom from pain. The actual outburst of severe pain may be preceded by obscure feelings of discomfort, itching or formication in the side of the face, flying pains about the teeth, or by a feeling of general malaise and shivering, but at other times a severe dart of pain shoots along the course of one of the branches of the nerve without being preceded by any warning. Each paroxysm consists of a succession of quick lightning-like darts of pain, which emanate from one or two foci and radiate toAvards the [)eriphery. At first one or two of these flashes may be followed by a com- paratively free interval, but they recur with increasing severity and (juickness, until they at last blend into an uninterrupted pain of great intensity, during the continuance of which the patient sufters indescrib- able agony. After one or two minutes the intensity of the shooting pain 246 DISOKDERS OF MIXED NERVES, abates, but the patient continues to suffer during the interval from a dull achinc^ pain, which occasions great discomfort and prevents sleep. The character of the pain during the paroxysm varies ; it may be burning, boring, cutting, crushing, or stabbing, although the lightning- like shocks are most frequently met with. The intensity of the disease may vary from an attack which consists of a few darts of pam or a Fig. 77. Skn^ory Nerves of the Head and Face. (At'ter Fi.oweu.) First division of the fifth : SO, Supraorbital. ST, Supratrochlear. IT, Infratrochlear. L, Lachrymal. N, Nasal. Second division of the fifth : 10, Infraorbital. T3I, Temporo-malar. Third division of the fifth : B, Buccal. M, Mental. AT, Auriculo-teniporal. Branches of the cervical plexus GO, Great occipital. S'O', Small occipital. GA, Great auricular. SC, Superficial cervical. IIIC, Third cervical. little tinghng of the face, and manifests no tendency to recur, up to a disease of the most obstinate character, that recurs repeatedly and with great severity during the whole of life, and in which an attack may be determined by such a slight exciting cause as a current of cold air on the cheek, or such actions as chewing, coughing, washing the face, or slight emotional disturbances. Painful points are observed during the attacks, and sometimes even in the periods of intermission, corresponding generally to the localities Avhere the nerve becomes more superficial, either in issuing from a bony canal or in penetrating fascias. NEURALGIA OF INDIVIDUAL NERVES AND PLEXUSES. 247 The ronroinitant symptoms of trigeminal neuralgia are very numer- ous. During a severe paroxysm the pain often radiates to other nerve territories, extending to the other branches of the fifth, when one only is primarily affected, or to the occipital, cervico-brachial, or intercostal sensory nerves. The skin is generally hypersesthetic in the early stages of the disease, and often anaesthetic in chronic cases. Disturb- ances of special sense have occasionally l^een observed in facial neural- gia, consisting of photophobia, amblyopia, or even amaurosis, and dis- orders of the senses of hearing, tasting, and smellino-. Motor disorders are almost always present in aggravated cases, and consist of clonic and tonic spasms of all the muscles of the affected side of the face, or of a few only of them, such as those of the eyelid or the angle of the mouth, while the muscles of mastication and of the tongue are sometimes attacked. Vaso-motor disturbances are manifested by pallor and coldness in the early stage of the attack, but these are quickly followed by intense redness and elevation of temperature, and then the skin 1)ecomes glossy and oedematous. The redness extends to the mucous membranes sup- plied by the affected nerve, the conjunctiva being specially liable to become red and congested; the carotid, facial, and temporal arteries of the affected side may be seen to pulsate strongly, and the side of the face is covered by beads of perspiration. Seeretory disorders are represented by an increased flow of tears, by arrest or increase of the secretion of the mucous membrane of the nose, and occasionally by augmented salivary secretion. The tropldc disturbances consist of swelling of the face, changes in the color and texture of the hair, herpes zoster frontalis, erysipelas, subacute inflammation of the periosteum and of the fibrous membranes in the neighborhood of the painful points, neuroparalytic ophthalmia, iritis, and glaucoma. In aggravated and long-continued cases the inces- sant pain and its attendant sleeplessness undermine the constitution, the general nutrition becomes impaired, and at last the patient suffers from marasmus and nervous exhaustion. The psychical disorders present are mental irritability and despon- dency, and hysterical seizures, whilst occasionally patients have com- mitted suicide to escape from their sufferings. Varieties of Trifjeminal Neuralgia, a. Ophthalmic or Supraorbital Neuralgia. In this form several branches of the first division of the fifth nerve (Fig. 78) are all aftected, or the pain is limited to some particular branch. 248 DISORDERS OF MIXED NERVES. The painful points are : (1) The supraorbital point, at or near the supraorbital foramen : (2) the palpebral, in tlie upper eyelid ; (3) the nasal, at the point of Fig. 78. DiAfiRAM OF THE FiRST AND SfxOND (SUPERIOR MaXILLARY) DIVISIONS OF THE KlFTH XeRVE, ITS Connections and Chief Branches. (From Hermann's " Phj'siology.") V, Placed over Casserian ganglion. a, First or ophthalmic division, with d its frontal, e its lachnjmnl, and/ its miml branches 6, Second or superior maxillary division, branches of wlilch are marked as follows : 1, Its terminal branches, nasal, labial, and palpebruL 2, Itecurrent branch to the ckira mater, and middle metdiujeid artery. 3, Oibital branch. 4 is placed between the two spheuo-palatiue branches (which descend to Meckel's ganglion) .5, Dental branches. MG, Meckel's ganglion. 6, The Vidian nerve (constituting the motor and sympathetic root of Jleckel's ganglion). 7, The ijreat svperficinl pttruml nerve, from the geniculate ganglion of the facial nerve, joining the Vidian. 8, The sympatlu'lic branch from the plexus on the carotid artery, joining the ijreat sKperficial petrosal, and forming with it the Vidian nerve 9, Ascending branches of Meckel's ganglion. 10, Descending palatine branches. 11, Naso-palatine branch. 12, Upper nasal branches. 13, Pharyngeal liranch F, Facial nerve. CA, Carotid artery. IF, Infraorbital foramen. emergence of the long nasal branch at the junction of the nasal bone with the cartilage ; (4) the ocular, a some-what indefinite focus 'vvithin NEURALGIA OF INDIVIDUAL NERVES AND PLEXUSES. 249 the globe of the eye when the ciliary nerves are aftected ; (5) the trochlear, at the inner angle of the orbit. The characteristic features of ophthalmic neuralgia are pain in the forehead, extending down-^-ards to the upper eyelid and root of the nose, hyperemia of the conjunctiva, lachrymation, and a painful spot at the supraorbital foramen. Malarial neuralgia almost ahvays assumes this form ; the attacks recur with great regularity, and are very intense. b. SUPRAMAXILLARY NEURALGIA. "When all the branches of the second division of the fifth nerve (Fig. 78) are affected the pain is situated in the cheek, eyelid, lateral portion of the nose and upper lip (infraorbital nerve), in the zygomatic arch and anterior temporal region (orbital nerve), in the upper row of teeth (dental branches), and in the nasal cavities and gums (naso-pala- tine and posterior palatine nerves). Infraorbital neuralgia is the most common variety of the second division of the nerve, and the characteristic pain is localized in the cheek, upper lip, upper row of teeth, and the neighborhood of the zygomatic arch. An ol)stinate form of neuralgia has been described by Gross which appears to have its seat in the remnants of the alveolar processes or the overlying gum in elderly persons who have lost their teeth. The painful points of supramaxillary neuralgia are : (1) The infra- orbital, corresponding to the emergence of the nerve from its bony canal; (2) the maJar, on the most prominent part of the malar bone; (3) an indeterminate focus somewhere in the line of the gum of the upper jaw ; (4) the superior labial, also indeterminate ; (5) the palatine, rare, but occasionally the seat of intolerable pain. c. Inframaxillary Neuralgia. When all the branches of the third division of the fifth nerve are affected the pain is localized in the region of the lower jaw and lower roAv of teeth (inferior dental nerve), in the chin (mental branch), in the tongue and mucous membrane of the mouth (lingual nerve), in the cheek (buccal nerve), and in the temporal region, anterior part of the auricle of the ear, and external auditory meatus (auriculo-temporal nerve). The painful points are: (1) The temporal, a little in front of the ear; (2) the inferior dental, opposite the point of emergence of that nerve; (3) the lingual, on the side of the tongue; (4) the inferior labial. The parietal point, a little above the parietal eminence, 250 DISOEDEES OF MIXED XEEVES. corresponds to the inosculation of various branches of the nerve, and may occur in all forms of trigeminal neuralgia. Fig. 79. DlAGK.VM OF THE THIRD (INFERIOR JIaXILLARV) DiVI.SION OF THE FiFTH NeRVE, ITS CONNECTIONS .*ND Chief Branches. fFiom Hermann's " Pliysiologj-.") V, Fifth nerve. (;, Its largest S(?nsory root, with Ciisserian ganglion. a, Its smaller motor root joining e, the thiril division of the Casserian ganglion, to fi>nii the inferior maxillary nerve. A, Anterior division of inferior maxillary nerve (mainly motor) supplying branches to the muscles of mastication, and a terminal hnccnl liranch to the mucous membrane of the mouth. B, Posterior division (mainly sensory) ; its branches are marked — 1, Lingual nerve ; 1', Branches to the tongue. 2, Inferior dental nerve ; 2' Its twigs to the teeth ; 2", Incisor branch ; 2'", Mental branch. 3, IVIylohyoid branch to digastric and mylohyoid. 4, Auriculo-temporal nerve. F, Facial nerve, ct, Its chorda ti/mp^ini branch, joining the lingual and running to the submaxillary gan- glion SG, of which it forms the motor root. OG, Otic ganglion : ssp, Ismail superficial petrosal nerve, connecting otU: ginglion and facial nerve. M, Middle meningeal artery, from the plexus upon which sympathetic filaments pa.ss to the oUc ganglion esp, External superficial petrosal nev\e, connecting the plexus on the middle meningeal artery with the facial nerve ; gsp. Great superficial petrosal nerve, connecting the facial with Meckel's ganglion. FA, Facial artery, from the plexus upon which sympathetic filaments pass to the submaxillary ganglion. FO, Foramen ovale. MF, ilental foramen SG, Submaxillary ganglion XEURALGIA OF IXDIVIDUAL XEEVES AXD PLEXUSES. 251 d. Epileptiform Neuralgia. In this form of facial neuralgia lightning-like pains of the most violent nature succeed each other with the gi-eatest rapidity for a few- seconds or minutes, and then suddenly vanish. These short attacks Fig. 80. Fig. 81. Figs. 80 and 81.— Cutaneous Xerves of the Trunk, Upper E.xtremitv. (After Flower.) Sa, Supraclavicular nerve. IID, Second dorsal. PS, Posterior branches of the spinal nerves. LI, Lateral branches of the intercostal nerves AI, Anterior branches of the intercostal nerves. II, Iliac branch of ilio-ingiiinal nerve. I'H', Ilio-hypogastric nerve. C, Circumflex nerve. IH, Intercostal humeral AV. Xerve of Wrisberg I'CB, Internal cutaneous branch of musculo-spiral nerve. ECB, External cutaneous branch of musculo-spiral nerve. ICB, Internal cutaneous nerve. MC, Musculo-cutaueous nerve. K, Kadial nerve. U, Ulnar nerve M, Median nerve. 252 DISORDEES OF MIXED NERVES. may, however, recur and follow each other in quick succession for a period of hours, days, or even weeks, when a respite follows, and the paroxysm disappears for days, weeks, or even years, although relapses are sure to recur after a longer or shorter time. This form of neural- gia is of centric origin, and occurs in families with a strongly marked neuropathic tendency, while it is often accompanied by epilepsy. 2. Cervico-occipital Neuralgia. Etiology. — Cervico-occipital neuralgia is usually excited by exposure to cold, and occasionally results from disease of the upper cervical vertebne. Symptoms. — The area of distribution of the great occipital nerve (Fig. 77, GO) is the region usually affected, but the pain may radiate widely into the area of distribution of the other branches of the cervical plexus, and even over the brows, temples, cheeks, or lower part of the ftice, so that the affection may be mistaken for trigeminal neuralgia. The most usual concomitant symptoms are hyperf^sthesia or an;v?stliesia of the occipital region, spasm of the cervical muscles, and considerable irritation and swelling of the cervical glands. The painful points are : (1) the occipital point, about midway be- tween the mastoid process and the spinous processes of the upper cer- vical vertebra; (2) the parietal point, over the parietal eminence. The track of the nerve over the occiput is often painful, and the spinous processes of the upper cervical vertebra are generally tender on pressure. o. Phrenic Neuralgia. It is believed by Peter that the phrenic is a mixed instead of being a purely motor nerve. The symptoms of phrenic neuralgia, as described by this author, are severe pains at the point where the nerve descends over the scalenus anticus muscle in its course through the chest, at the anterior and lower part of the thorax, and along the line of attach- ment of the diaphragm. Pain in the shoulder is a constant and charac- teristic symptom. Phrenic neuralgia is usually a symptom of epilepsy, hysteria, and angina pectoris, and is met with occas'^ionally as a sei)arate affection. The painful points are: (1) The spinous processes of the upper cervical vertebrae; (2) the phrenic nerve in its course along the sub- clavicular fossa ; (3) the line of attachment of the diaphragm, especially anteriorly between the seventh and tenth ribs ; (4) a point over the cartilage of the third rib. NEURALGIA OF INDIVIDUAL NERVES AND PLEXUSES. 253 4. Cekvico-brachial Xeiraloia. Etiology. — The most important exciting causes are the various in- juries to which the upper extremities are so peculiarly exposed. It may also be caused by lead-poisoning and malaria, and may be a symptom of central diseases, as tabes hemiplegia and proc^ressive mus- cular atrophy. Si/rnptoms. — Cervico-brachial neuralgia occurs in the area of distri- l)Ution of the sensory branches of the brachial plexus (Figs. 80 and 81) and the posterior branches of the four lower cervical nerves. The pain is more or less continuous, and is of a dull, boring, or burnino- char- acter, interrupted by paroxysms of lancinating pains, which shoot through the arm along the course of the nerves. It often occurs in nocturnal paroxysms which last through the night and may disap])ear during the day. The pain may have its seat in the upper arm or fore- arm, or may extend into the hand and fingers, but it is generallv widely distrifented, and the intimate interweaving of the various nerve trunks in the plexus renders it difficult to determine what nerve roots or l)ranches of the plexus are implicated. When the pain is situated near the periphery it may be limited to one branch of a nerve. The violent burning pain described by S. Weir Mitchell under the name of '"causalgia" is often present in the neuralgiie which result from gun- shot injuries of the nerves. The pcmiful points, which are somewhat indefinite, are: (1) an axillafy pointy corresponding to the brachial plexus; (2) ^ scap)ular ^^o/n^, corresponding to the lower angle of the scapula; (3) a shoulder point, corresponding to the emergence through the deltoid of the cutaneous branches of the circumflex; (4) a mrdian cephalir jjoint, at the bend of the elbow ; (5) an external humeral point about three inches above the elbow; (6) a superior ulnar point, over the ulnar nerve in its course between the olecranon and the epitrochlear ; and (7) a radial point, where the nerve becomes superficial at the lower and external aspect of the forearm. Painful points may occasionally be developed by the side of the lower cervical vertebrtie, corresponding to the posterior branches of the lower cervical nerves. The concomitant symptoms consist of cutaneous hypersesthesia, numb- ness, and formication, or a considerable degree of ana?sthesia. Radiat- ing pains are felt in the region of distribution of the cervical plexus, and of the upper dorsal and intercostal nerves. The motor disorders consist of twitchings of the muscles of the upper extremities, and in aggravated cases they may be maintained m 2o4 DISOEDEES OF MIXED NEEVES. :i State of persistent spasm. In chronic cases some of the muscles may he enfeebled or completely paralyzed, but neuritis is then probaldy present. The vaso-motor disorders are coldness and pallor, or redness and heat of the affected extremity. The trophic disorders consist of eruptions of herpes, Ijut the aggra- vated cases which are caused by gunshot and other injuries of the nerves are complicated by pemphigus, obstinate ulcers, glossy skin, and changes in the groAvth of the nails and hair. 5. DORSO-INTERCOSTAL NeURAL(;IA. Etiology. — Women are especially liable to this form of neuralgia. It comes on usually between the ages of twenty and forty years, in nervous, hysterical, and anemic subjects, and its usual exciting causes are oversuckling, menorrhagia, and leucorrhoea. The exciting causes of dorso-intercostal neuralgia are exposure to cold, injuries of various kinds, neuritis, neuromata, disease of the ver- tebnie or ribs, aortic aneurisms, pulmonary phthisis, dilatation of the venous plexus in the interior of the vertebral canal, and diseases of the spinal cord, such as transverse myelitis, spinal meningitis, spinal and meningeal tumors, and locomotor ataxia. Symptoms. — The pain of intercostal neuralgia is seated in the area of distribution of the sensory branches of the twelve pairs of dorsal nerves; it is of a dull, and tensive character, and is usually continuous, but it is occasionally interrupted by tearing, lancinating, or burning pains. The pain is aggravated by all violent respiratory movements, and by slight pressure on the skin, but it is often relieved by firm and steady pressure. The pain not infrequently radiates tOAvards the back and arm, or into the loins or lower extremities, and this form of neuralgia may be associated with brachial and lumbo-abdominal neural- gia, or with angina pectoris. The seat of true intercostal neuralgia is the skin of the anterior and lateral wall of the thorax and abdomen as far down as the symphysis pubis, and when the first two nerves are attacked the pain extends to the axilla and inner surface of the arm. When the posterior branches are affected the pain is seated in the back an,SV///^;>fo;»«.— Gastralgia is characterized by paroxysmal attacks of pain in the epigastric region which may radiate upwards to the back between the shoulders, or to the middle of the sternum. The attack comes on suddenly, without premonitory symptom, and the pain, whicli is very severe, generally intermits after a few minutes, but soon recurs with greater intensity, and after repeated intermissions and recurrences it finally disappears. Pressure over the cartilages of the false ribs on the left side, or on the corresponding intercostal spaces, may cause pain, and the spinous processes of some of the dorsal vertebrae may be tender on pressure. Tlie pain of gastralgia is relieved by firm and uniform pressure, and tenderness of the epigastrium is generally absent. The upper portions of the recti muscles are strongly contracted during the attack and the abdominal walls are rendered tense and unyielding, whilst the epigastric region is usually retracted. The pulse is generally slow and feeble; the arterial tension is low; the extremities are cold and pale ; and towards the end of the attack the patient may suffer from chilliness and a feeling of oppression and faintness like that of angina pectoris reflectoria. The attack often terminates by copious vomiting, the food contained in the stomach is first ejected, and then large quanti- ties of watery fluid mixed with bile and blood, and in aggravated cases, mucus; while if the urine be examined during or soon after the attack it is often found to contain a small (piantity of albumen. Tabetic gastric crisis is a variety of gastralgia which ])egins during an attack of the lancinating pains of locomotor ataxia. The jiatient complains of pain which starts from the groins, and passes up each side of the abdomen to become fixed in the epigastrium, while at the same time severe lightning pains dart from between the shoulders and radiate round the base of the thorax. Severe vomitincr now sets in, just as occurs in all severe cases of gastralgia. The patient suffers during the attack from a profound malaise ; the action of the heart is accelerated, and the lightning pains are unusually severe. The attack may last without respite for two or three days, and may recur every two or three weeks although the usual interval betAveen them is not less than a month. d. Neuralgia Hepatica {Hepatalgia). Etiology. — Hepatic colic is usually the result of the passage of biliary calculi through the cystic and common ducts, but colic of similar char- acter sometimes occurs in neurotic subjects in the absence of any signs of biliary obstruction and it is regarded as of purely neuralgic origin. NEURALGIA OF INDIVIDUAL NERVES AND PLEXUSES. 265 Symptoms. — The symptoms of hepatic colic are more or less severe pain which comes on suddenly and lasts with irregular intermissions and exacerbations from a few hours to a few days. The pain is often very severe, and of an aching, cutting, or tearing character, and is usually attended with a feeling of constriction or cramp. It is o-enerallv referred to the pit of the stomach or to the umbilicus, whence it radiates to the back and between the shoulders, but never downwards. The patient suffers during a severe attack from faintness, nausea, and vomit- ing ; the action of the heart is Aveakened, the surface of the body is cold, and in severe cases there are symptoms of collapse. (\ Neu7'algia Hypog<(strica. Hyposastric neuralgia mav be divided into the followino- varieties according to the branches of the plexus affected, (1) Neuralgia Ani. Etiology. — Neuralgia of the rectum generally results from fissures of the anus, but it may occur in the absence of any recognizable local cause ; and it is a common symptom of locomotor ataxia. Symptoms. — The symptoms consist of severe paroxysms of cutting pains coming on suddenly and si)ontaneously after exposure to cold. The pains are situated an inch within the anus, and they are much in- creased by defecation. The pain is associated with hypersesthesia or an;esthesia of the skin of the perineal region, spasm of the sphincter ani and bladder, and difficulty of micturition. (2) Neuralgia Uteri (Hysteralgia). Etiology. — The causes of uterine neuralgia are prolapse of the uterus, uterine tumors of all kinds, ulceration of the cervix, profuse and in- tractable leucorrhoea, ascarides in the rectum, scybala impacted in the rectum, and calculus in the ureter or kidney. Sometimes the source of irritation may be in a remote part of the body, and in some cases paroxysms of uterine neuralgia may occur in the absence of any dis- coverable disease of the pelvic organs. Symptom,s. — The patient complains of paroxysmal attacks of intense pain situated deeply in the pelvis which is aggravated by movement, by the maintenance of the erect posture, and by pressure on the cervix. The pain often radiates to the inguinal and lumbar regions of one si■) 18 274 PISOBDERS OF CRAXIAL XERVES. Disorders in the perception of light ; and {d) Disorders in the percep- tion of colors. (a) Diminution in the Acutenes^ of Vision.— "iXie patient sees objects through a mist ; he has difficulty in distinguishing minute objects, or at times may observe a dark spot in the centre of vision. Tests of the Acuteness of Visio?!.— The acuteness of vision is usually tested by asking the patient to read print of a certain size of type, and at definite distances. In Snellen's scale the size of type is numbered according to the distance in feet at which the print can be read by the normal eye in a good light. The acuteness of vision is expressed by a fraction of which the denominator is the number of the test type, and the numerator the distance in feet at which it can be read. The sight of each eye must always be tested separately. (b) Alterations in the Field of Vision. — The field of vision may be altered in several ways, but the form usually observed in functional amblyoi)ia begins at the margin of the field and progresses concentri- cally until only a small central area is left. The first loss of vision may appear in the centre of the field, constituting a central scotoma, while at times the whole field of vision is covered with scotomata. The blindness may sometimes be surrounded by spectral appearances and then it is named a scintillatinc) scotoma. In their simplest form they consist of a blind area which is surrounded more or less completely l)y a luminous border, the latter Avidening as the former expands. This luminous arc is subject to a rapid oscillatory movement which has been variously described by different observers. In the more pronounced forms the luminous border assumes a zigzag outline which has been compared to the outlines of a fortification. It is also fringed l)y gorgeous colors which are in continual trembling movement, or appear to ''corus- cate," or to emit a "shower of sparks." The phenomenon lasts from a quarter to half an hour and then passes off". Tests of the Field of Vision. — The most ready test of the field of Aision is to direct the patient to fix one eye, the other being closed, on the corresponding eye of the operator, and the latter then moves his hand to the right, left, above, and below, and at a certain distance from the fixed point as a centre. If the field of vision be limited in any particu- lar direction, the observer will have to approach his hand nearer and nearer to the point on which the patient's eye is fixed before it is seen, and thus any serious departure from the normal limit can be readily detected. If greater accuracy be required, the field must be measured by means of the " mapping system " or by the perimeter, for a descrip- tion of which the reader is referred to ophthalmological works. DISORDEKS OF THE XERVES OF SPECIAL SKX3E. 27." ::LiO (c) Disorders of the Perception of Light. — There are several varieties of partial anaesthesia in which the ophthalmoscopic appearance may be negative. Sometimes the patient cannot see at night, a condi- tion which is called henwralopia ; at other times sight is deficient in daylight, and this condition is called nyetalopia. (d) Disorders of the Pereeption of Colors {Dyschromatopsia, Achro- matopsia). — The perception of colors may be defective when the acutencss of vision is very little impaired, and, conversely, color vision may be little aflected when there is considerable limitation of the field of vision. The area of the field of vision varies for each color, green havino- the smallest and yellow and blue the largest visible areas (Fig. 85). Fig. 85. DiAiiRAU Showing the Fiklds of Color Vision in a Normal Emmetropic Eye on a Dim. Day. (After GowERS.) Tlie fields are each ratliei- smaller than on a bright day. The asterisk indicates the fixing- point, the black dot the position of the blind spot. (U.sually the blue field is larger than the yellow.) Tests of Color Vision. — A scale of colors is submitted to the patient and it must be ascertained whether he can identify and name each ; or the patient is asked to match a given color from a number of others presented to him. In amblyopia the order in which the percej)tion of colors is lost is usually that in which the fields are arranged on the retina, the first defect beino; for o-reen, then red, while yellow and blue are the last to be lost. The condition in which central vision for the perception of one or more colors is much restricted is named dyschromatopsia, while total color blindness is named achromatopsia. Color blindness is sometimes a congenital defect, and of tins form there are three varieties; namely, (1) Red blindness, (2) (irecii blind- 276 DISOKDEKS OF CRANIAL NERVES. uess, and (^J) Violet blindness. Dalton suffered from red-blindness ; he imagined that diluted ink gave a color much resembling a florid com- plexion ; blood appeared to him not unlike in color to that called bottk-- areen • and he could not distinguish between the color of a ripe cherry and that of a leaf. b. Orjiiinic Bisi'ases of the OjJtic JVcrvc^. Optic Neuritiif: and Atrophy. Etiology. — Ojitic neuritis may l)e caused by tumors of the brain, hydrocephalus, basal meningitis, meningeal hemorrhages, and throm- bosis of the cavernous sinus, but it only rarely results from abscess of the brain, and softening from occlusion of vessels, and in the few cases in Avliich it was associated with hemorrhage it may be suspected that a tilioma was jjresent. Optic neuritis is occasionally observed in cases in which the symptoms point to intracranial disease, but in which the ])ost-mortem examination reveals no lesion. It may also be caused by extracranial causes, such as orbital tumors, and inflammation of the bones, periosteum, or cellular tissue of the orbit, and hyperostosis nar- roAving the optic foramina. Optic neuritis sometimes follows injuries of the cervical spine, while it has occasionally been observed in caries of the cervical vertebrit;, witli transverse myelitis of the cervical and dorsal regions of the cord. Double optic neuritis is sometiuics caused by acute diseases, suc-h as the specific fevei's and pneumonia. I'Xposure to C(dd or to a very bright light, suppression of the menses, or chronic blood-poisoning from lead, syphilis, diabetes niellitus, or chronic liright's disease. Varieties. — The diseases of the optic nerves may divided as follows : (1) Congestive and inflammatory affections : (a) Simple congestion of the disk. {b) Congestion with swelling of the disk (optic neuritis). ((') Albuminuric retinitis and neuritis. (2) Atrophic affections: (a) Simple or primary atroj)hy. {b) Secondary atrophy. (1) Inflammatory Affections of thk Optic Nerve. {'() Simple congestion is characterized by an increased redness of the disk, Avhich is the more readily recognized when it is greater in one eye than in the other. The redness invades the })hysiological cup and may entirely obscure it; the sclerotic ring and the edge of the choroid are rendered indistinct, and the disk loses its sharpness of outline. DISORDERS OF THE XEKVES OF SPECIAL S K X S E . 277 (/>) Optic neuritis is characterized b}' (edema as well as congestion of the disk, which becomes enlarged, swollen, red, and cloudy, the physio- logical cup is obscured, the sclerotic ring and the edge of the choroid are concealed, and the edges of the disk are l)adly defined and hazv. As the disease advances the disk becomes more swollen, it assumes a reddish-grav color, and its periphery becomes distinctly striated, partly owing to the swelling and opacity of the nerve fibres and partly to an enormous development of minute vessels. The veins are enororored tortuous, and often varicose, while the arteries are reduced in size, and a])pear paler than the veins, ^Vhen exudation takes place the vessels become veiled and lost to sight at the boi'der of the disk, but reappear partially as they proceed inwards, and disappear again l)efore reaching the lamina cribrosa. The inflammaticm may now subside, the swelling gradually dimin- ishes, the edge of the choroid becomes apparent, and the only indica- tion of the previous inflammation which remains may be a narrow zone of atmphy adjacent to the disk and along the edge of the choroid. (j) I:J)i;/07yed or Choked Disk. — If the inflammation continues the r engorged disk. (jj) Subsidence of Optic Neuritis. — After the strangulation has existed for some time the veins become less distended, the swelling loses its intense red color and becomes pale and less prominent, hemorrhages cease, the extravasated blood is absorbed, leaving pigmented or white spots on the retina, the edges of the choroid and the sclerotic ring become dimly apparent after a time, and then the (hsk assumes a whitish or grayish color, its edges being generally irregulai- and sur- rounded by a zone of choroidal atrophy. (jjj) Descending Neuritis or Neui-o- retinitis. — It is not often pos- sible to distinguish during life between neuro-retinitis and the slighter decrees of eno-orored disk. In neuro-retinitis there is only a slight r5 c o 111 deo-ree of swellincr, the changes are more marked towards the edge than in the centre of the disk, hemorrhages are absent, white spots 278 DISORDERS OF CRANIAL XERYES. may be seen scattered over the disk or along the edges of the vessels, and the disk has a striated appearance from atrophy of the nerve fibres. (iv) Retrobulbar Neuritis and Perineuritis. — In retrobulbar neu- ritis the primary congestion soon passes on to atrophy with narrowed vessels. It is met with in periostitis of the orbit and in cases where the optic nerves are constricted by thickening of the cranial bones. Optic perineuritis results from chronic inflammation of the sheath of the nerve, which gives rise to thickening and purulent infiltration of the trabeculse, and it generally ends in optic neuritis. (v) Albuminuric Retinitis and Neuritis. — In diseases of the kidneys the arteries of the retina become diminished in calibre like the arterioles of the body generally. As the disease advances the retinal arteries are reduced to small lines, and when swelling is present they may be invisi- ble beyond the edge of the disk, while the thickening of their walls causes white lines to appear along their edges. The arteries are liable to undergo aneurismal dilatations, and retinal hemorrhages form a marked feature of the affection. Albuminuric retinitis ])resents several varieties, viz., (a) degenerative, {b) hemorrhagic, and [<■) inflammatory retinitis, to which may be added, according to ( Jowers, {d) albuminuric neuritis. (a) Begenerative Albuniinurie Retinitis. — This form, which is the most common, begins by the appearance of white spots on the retina; they are small and rounded at first, but after a time increase in size and become irregular in outline, while neighboring spots sometimes coalesce to form large white patches. Small white spots are generally to be seen around the macula lutea; they are sometimes so small as to be seen only on careful direct examination, but are at other times large and well marked, and arranged end to end, so as to form ladiating streaks irregularly disposed around the macula, and giving to the retina at this part a silvery appearance. {b) Hemorrhagic AJbuminurir Retinitis. — The chief characteristic of this variety is the large number of hemorrhages which occur, and white spots only appear around the macula lutea at a late stage of the affection. {c) Inflammatory Albuminuric Retinitis. — In this variety there is general swelling of the retina, the disk is obscured, the arteries are thready and numerous, the veins are distended and tortuous, with irregular outline, and large hemorrhages often occur, while the white spots are often numerous and well marked. On the subsidence of the inflammation the optic nerve may undergo secondary atrophy. [d) Albumhiuric Neuritis.~ln this affection inflammation of the optic nerve predominates over the retinal changes, the ed^es of the DISORDERS OF THE NERVES OF SPECIAL SEXSE. 279 disk are indistinct and veiled under a grayish-red swelling, and the arteries are small and often hidden, while even the veins may be con- cealed in the swelling, and form curves over the sides of the swollen disk. White spots may be seen on the surface of the swollen disk, on the retina, and around the macula lutea, and small hemorrhages may be observed about the fundus, but are rare over the swollen disk. When the inflammation subsides a consecutive atrophy of the optic nerve may be left. Albuminuric neuritis cannot often be distinguished from ordinary optic neuritis. General Symptoms. — Sight may remain unimpaired in advanced cases of optic neuritis, and when amblyopia is present its degree is by no means proportional to the amount of change observed on ophthal- moscopic examination. Vision is likely to fail sooner in descendino- neuritis than in cases of engorged disk, while a high degree of uni- lateral or bilateral amblyopia may precede for some time anv changes in the fundus in retrobulbar neuritis. The cerebral symptoms most likely to be associated with optic neu- ritis are headache, vertigo, vomiting, loss of memory, unilateral epi- lepsy, hemiplegia, and paralysis of some or all of the ocular muscles. 3Iorbid Anatohiy. — In order to understand the mechanism by which the swelling of the disk is caused in optic neuritis, the anatomy of the nerve must be kept in mind. The annexed diagram (Fig. 86) will suffice to remind the reader of the structure of the nerve. Inflamma- tion of the optic nerve gives rise to a serous infiltration which augments its volume and diminishes its consistence. The sheath of the nerve is often distended with fluid, the connective tissue of the pial sheath and of the trabeculge surrounding the nerve bundles becomes thickened and infiltrated with nuclei and cells, a considerable number of leucocytes is found surrounding the vessels, and the nerve fibres undergo degen- erative changes, while in advanced cases the tissue of the lamina cribrosa is distended and its structure altered. The veins are large and tortuous, but the arteries are abnormally small. Various theories have been advanced to account for the different forms of optic neuritis. Descending neuritis and perineuritis of the nerve are caused by a local disease and need not be further discussed. But the double optic neuritis, or choked disk, which is caused by the presence of an intracranial tumor does not find a ready explanation. It was suggested by Von Graefe that the increase of intracranial pressure which results from the presence of a tumor within the skull caused an obstruction to the flow of blood from the eyes by compressing the cavernous sinus. ]Many objections have been urged against this theory, and it was finally abandoned when Sesemann showed that the supraorbital vein 280 DISORDERS OF CRANIAL NKRVES. anastomoses so freely with the f^u-ial veins, that pressure on the cavernous sinus would only produce a very temporary effect. When it was dis- covered l)v Schwalbe that the subvaginal space around the oi)tic nerve was continuous witli the subdural space around the brain, Schmidt sufTo-ested that any increase of intracranial pressure would tend to dis- tend the sheath of the optic nerve with fluid, and consequently Avould produce strancrulation of the nerve fibres in tlieir passage through the sclerotic ring and Inmin;! cribrosa. Tliis theory is by no means free Fk;. 86. ~^^' / r'J.HllTiMllltQirlrlAiaiaill'XA. inn A ti /> HoHi/.oNTAi, Section through thk utth Nkrve at its Point ok Insertion in thk »;i,obf,, anh it.< Passage through the JIembranes of the Eye. (P'rom Landois's " Ph.vsiologie "l a, Internal ; ft, External layers of the retina ; c, Choroid ; d, Sclerotic ; e. Physiological cup ; f. Central artery of the retina; ti (CG) ; a' b, Fibres which do not decussate in the chiasma; b' a', Fibres coming from the right eye, and coming together in the left hemisphere (LOG) ; K, Lesion of the left optic tract producing right lateral hemianopsia ; A, Lesion in the left hemisphere (LOG), produces crossed amblyopia (right eye). T, Lesion producing temporal hemianopsia: NX, Lesion producing nasal hemianopsia. the fields of vision this condition is called double temporal hemianopsia. In- this defect patients experience difficulty in walking, but they are often able to read the smallest print. Douhlc nasal hemianopsia is rare, and can only result from a double lesion (Fig. 87, N N). Y. DISOKDEKS CAUSED BY DISEASE OF THE CEREBRO-SPINAL SENSORY CONDUCTING PATHS. Various sensory disorders are caused by disease of the fibres of the posterior roots after they join the spinal cord, but inasmuch as these fibres are affected most frequently in posterior sclerosis, the resulting dis- orders will be considered along with tabes dorsalis. Parancesthesia. — In transverse lesions of the spinal cord the part of the body which is innervated from that portion of the cord which lies below the level of the lesion is more or less anaesthetic, according to the completeness of the destruction of the cord produced. A hyper- ])ISEASh: OF CEREBKO-SFIXAL SENSORY PAl'irs. -iS.") iVi^sthetic belt is tiequently met Avitli suirounding the body on a level Avith the iipi)er limit of the lesion, caused by irritation of fibres descend- ing from the posterior roots which are situated immediately above the level of the lesion. Hejiiiparancesthesia. — In destructive lesions of one hiteial half (.f the spinal cord there are, on the side of the lesion, motor paralysis and loss of muscular sense below the level of the lesion from destruction of the fibres of the pyramidal tract, cutaneous hypemesthesia of the parts below the level of the lesion from irritation of the sensory conducting paths of the opposite half of the spinal coitl, an anaesthetic belt on a level with the lesion from implication of the posterior roots, and u hypcr- sesthetic belt above this level from irritation of fibres descending from the posterior roots immediately above the lesion. On the side opposite to the lesion there is anaesthesia of the sensations of touch, pain, tem- SeCTION 01' THE MeDI I.LA OllLliXr.ATA nX A LEVEL WIT}I THE LAEGEST lHAMETEi; OF THE DISEASED FOCUS, WHICH IS KErRESENTED BV THE SHADED PART ON THE LEFT HALF OF THE DIA(iRAM. (After SENATOR. ) P, pyramids ; ol, olivary bodies ; Voir, ascending root of tlio fifth m-rve ; A7.-, nucleus of the vagus ; Xiuk, motor nucleus of the vagus; lib, fasciculus rotundus ; x, the vagus; xii, the hypoglossal nerve. perature, and tickling of the parts supplied from beloAv the upper limit of the lesion, from destruction of the sensory conducting ])aths after thev have crossed over to the opposite side of the cord, and a zone of hypersesthesia immediately above the level of the upper limit of the lesion caused by irritation of fibres descending from the posterior roots immediately above the lesion, and some of which jirobably cross over to the diseased side of the cord. In unilateral lesions of the lumbar or the cervical enlargements a zone of anaesthesia is found in the lower or upper extremities wdiich varies in its position according to the level of the lesion, and the root or roots which are involved in it. 280 DIS<^Kl)EPiS OF CEREBRO-SPINAL SENSOEY PATHS. Crossed HemianCBstheda. — In this affection there is ansesthesia of the face on one side of the body, and of the trunk and extremities on the opposite side. In a case of this kind reported bv Senator the lesion consisted of a spot of softening in the restiform body, and impli- cated the ascending root of the fifth nerve (Fig. 88). It must be re- membered that this root begins as low down as the third cervical nerve, so that some det^ree of anaesthesia of the side of the face ma}' be observed in unilateral lesions of the upper portion of the cervical region of the cord. Hemiancesthesia. — In this affection there is loss of sensibility of the whole of one-half of the body, face, and extremities, including the accessible mucous membranes as well as the skin. The abolition of sensation is sometimes incomplete, and then cutaneous analgesia or thermo-aniesthesia may be present, while tactile sensibility remains unaffected. At other times the anaesthesia of the skin and mucous membranes is complete, and even muscular sensibility and muscular sense are abolished. The patient, for instance, does not feel deep pressure, strono- contraction of the muscles may be produced by the faradic current without causing pain, and Avhen his eyes are closed he is unable to describe the position in which the affected extremities may be placed by passive movements, and is not aware when his attemjjted voluntary movements are forcibly prevented. The patient can walk Avithout difficulty Avhen his eyes are closed, but by slight pressure upon the affected side he may be easily induced to walk in a circle while under the impression that he is walking in a straight line. One hnlf of the mucous membrane of the tongue, mouth, veil of the palate, and the conjunctiva of the same side are insensitive, but the cornea retains its sensibility. The affected side feels cold to the touch, and the ])rick of a pin does not bleed so readily as on the opposite half of the l)ody. The cutaneous reflex actions may be lost on the affected side Avhile the deep reflexes are retained. The senses of taste and smell are abolished on the affected side. The sense of hearing is diminished, and in some cases there may be complete unilateral deafness. The sense of sight is impaired, l)ut not abolished. There is concen- tric restriction of the field of vision, and the perception of colors is diminished or lost [dgsehronuitopsia), these defects being present in both eyes, but most marked on the side opposite the lesion. Hemiancesthesia as just described occurs in its most typical form in hysteria and occasionally in epilepsy, chorea, neurasthenia, and other grave neuroses. It also occurs in organic diseases Avhen the lesion is situated in or near the posterior third of the posterior segment of the DISORDEES OF C EREBE O - SP I X AL SEXSORY PATHS. 287 internal capsule. Hemiansesthesia is generally present in hemichorea and athetosis, the lesion being situated in these diseases either in tlie external and posterior part of the optic thalamus or in the posterior part of the lenticular nucleus. In these diseases the posterior part of the internal capsule is only partially injured and the degree to wliich sensory conduction is impaired varies greatly in different cases. When the lesion is situated on the lenticular nucleus the various forms of cutaneous and muscular sensibility are aifeeted, but the special senses often remain intact. The special senses may also remain unaffected Avhen the posterior part of the internal capsule is compressed bv the growth of a tumor in the optic thalamus, probably because the slow growth of the tumor enables the fibres of the optic radiations of Gi-atiolet to be pressed aside without rupture. Hystei-ical hemianfesthesia is associated, as Ave have just seen, with concentric restriction of the fields of vision of both eyes, and especiallv with amblyopia of the eye on the same side as the other sensory dis- orders. In order to account for this fact, Charcot assumed that all the fibres which come from one eye are connected with the cortex of the opposite hemisphere, and he supposed that for the fibres w^hich did not cross in the commissure there was a suj)plementary crossing in the corpora quadrigemina (Fig. 87, T Q). But that part of the scheme which relates to the supplementary crossing is now, I believe, abandoned by its distin- guished author, because a considerable number of cases are now recorded in which homonymous lateral hemianopsia has been caused by disease of one cerebral hemisphere, the lesion being situated in such cases on the pulvinar of the optic thalamus, the white substance of the occipital lobe, or the cortex of the occipital lobe as far forwards as the angulai- gyrus. From an analysis of recorded cases it would appear that the fibres of the optic tract pass through the geniculate bodies and anterior tubercle of the corpora ((uadrigemina, and are continued upwards through the pulvinar of the optic thalamus, the posterior part of the internal capsule, and the posterior part of the corona radiata, to reach the cortex of the occipital lobe. In homonymous hemianopsia caused by disease of one optic tract, central vision is retained in both eyes, a fact Avhich proves that the macula lutea of each eye must be connected with the corticles of both hemispheres. As the organs of vision are bilaterally associated in their functions, it is pi-obable that the cortical visual centres are connected by commissural fibres through the corpus callosum. 288 DISORDERS OF CORTICAL SKXSORY CENTRES. VI. DISORDERS CAUSED BY DISEASE OF THE CORTICAL SENSORY CENTRES. 1. Cutaneous and Muscular 1Ie.ml\n.ksthesia. Ferricr localizes the centre of tactile sensibility in the hippocanijial region, but unilateral lesions of these convolutions are not known to o-ive rise to anesthesia. Disease of the temporo-sphenoidal lobe some- times causes loss of tactile sensibility of the opposite side, but it is most probably caused by interference with the sensory fibres of the internal capsule. Cutaneous aniesthesia and loss of muscular sense have occa- sionally been found associated with hemiplegia in cases of extensive softening of the cortex of the parietal lobe, and it is, therefore, probable that the cortical centre of general sensil»ility is widely diffused over the so-called motor area of the cortex. 2. DlSOUDKKS OF THF SeNSE OF S.MKl.L. a. Hnlluritiations of Smell. — The case of a woman is reported by Dr. McLane Hamilton, Avho had for nearly thirty years suffered froih occasionally recurring e]tile[)tiform attacks which were always ushered in by an aui-a of a disagreeable (jdor. The patient died of phthisis, and at the autopsy the pia mater was found adherent over the right uncinate gyrus and adjacent convolutions, while the subjacent gray matter was atrophied and in a state of sclerosis. The olfactory neives were not involved in the lesion. /'. Anosmia. — FeiTier found that destruction of iXw.sahtcuhini cornu amnionis in monkeys caused loss of smell on the side of the injury. but in heiJiiancesthcsio from disease of the fibres of the posteri<»r part of the internal capsule the loss of smell is on the side opposite the lesion. Anosmia of the left nostril is S(»metimes met Avith in cases of right hemiplegia and aphasia, but the loss of smell is most probably caused by softening of the external root of the olfactory tract and not from disease of the cortex. A case of abscess of the temporo-sphenoidal lobe is reported by Dr. Glynn, in which the most prominent symptom was complete anosmia, l)ut the loss of smell was most prol)ably caused by compression of the olfactory tracts at their points of junction with the brain. On the whole, our clinical information with regard to the localization of the cortical centre of smell is exceedingly scanty and will not bear a critical investio;ation. I DISEASES OF THE COKTICAL SEXSOKY CEXTEES. 289 •S. Disorders of the Auditory Sense. a. Hallucinations. — Ferrier places the auditory cortical centre in the first and second convolutions of the temporo-sphenoidal lobe, and irritative lesions of these convolutions give rise occasionally to hallucina- tions of hearing. A man, under my care, received a blow over the head a little above the left ear, and at the seat of injury, which was opposite the first and second temporo-sphenoidal convolutions, a slight depression in the bone could be detected. After the injury the patient suffered from recurring epileptiform attacks which were ushered in by loud rattling noises, caused most probably by a discharging lesion havin^ its origin in the auditory cortical centre. h. Psyehical Deafness. — In this condition, which was first described by Goltz as occurring in dogs after portions of the cortex of the brain had been washed away, the animal is not deaf, but fails to recognize the significance of the usual calls. He does not, for example, respond to the call of his name, and is not cowed by angry threats, and yet distinct evidence is obtained that he hears noises. This defect was named psychical deafness by Munk. The state in man most nearly approaching to it is word-deafness., which will be subsequently described along with the disorders of speech. c. Absolute Deafness. — Unilateral destructive lesions of the first and second temporo-sphenoidal convolutions do not give rise to complete deafness of one ear, because the sense of hearing is bilaterally associated, and so long as one hemisphere is unaffected the auditory sense remains unimpairevl or only slightly weakened. The condition which will be subsequently described as word-deafness is, however, associated with disease of the first and a portion of the second temporo-sphenoidal con- volutions. But if the first and second tem})oro-si)henoidal convolutions contain the auditory centres, bilateral lesions of these ought to give rise to complete deafness. A case is reported by Wernicke in which the patient first suffered from word-deafness and subsequently became com- pletely deaf, and after death the first temporo-splienoidal convolution was found softened in each hemisphere. A careful dissection of the ears proved the absence of any local disease of the peripheral organ of hearing. 4. Disorders of the Visual Sense. a. Halluei7iations of Sight. — Tumors of the occipital lobe give rise to hallucinations of sight such as colored vision, and the images of animals and of variously dressed men, and when the growth causes epileptiform convulsions the attacks are often preceded by a visual aura. 19 290 DISORDEES OF THE VISUAL SENSE. b. Psychical Blindness.— Ti\\& condition was, like psychical deafness, first observed by Goltz in dogs after portions of the cortex of the brain were washed away. The dog, after the operation, sees and avoids obstacles, thus recognizing resistance and the other fundamental prop- erties of matter, but he has lost the power of appreciating the special properties of matter to so great an extent that he does not recognize his food as such. A more or less similar condition has been descril:)ed hx Fiirstner as occurring in some cases of general paralysis of the insane. The patient, for example, recognizes that a piece of money placed in his hand is a metal, but has lost all knowledge of the special properties which constitute it a coin. Word-blindness is a more or less similar condition. Subsequent dissection has proved that in the dogs operated upon by Goltz, it was the posterior lobes of the brain which were chiefly denuded of cortex by his method of procedure, and in Fiirstner"s cases the cortex of the occipital lobes was always found diseased when a post-mortem was obtained. It will be hereafter seen that in word-blind- ness the disease is limited mainly to the cortex of the angular gyrus. c. Homonymous Bilatcnd Hemianopsia. — Man^^ cases are now re- corded in which this defect of sight was caused by softening of the cortex of the left angular gyrus, and the condition is frequently associated with word-blindness. d. Absolute Blindness. — Disease of the cortex of one hemisphere of the brain does not usually give rise to complete blindness. The case of a boy, however, is reported by Dr. Abercombie, who, after an injury which caused a depressed fracture of the right parietal bone, suftered from hemiplegia of the left side and amaurosis of the left eye, from which he made a quick recovery on the depressed part being removed. The position of the fracture rendered it probal)le that the angular gyrus was injured. A case is reported by Dr. Glynn, of Liverpool, in which the patient became suddenly and completely blind, and in which a clot was found occluding the posterior cerebral artery of the left side, causing extensive softening of the left occipital and temporo-si)henoidal lobes. The case of a woman is reported by Dr. Shaw, of Brooklyn, who had become suddenly aphasic and perfectly deaf and blind. At the autopsy the angular gyri and superior temporo-sphenoidal convolutions of both hemispheres were found completely atrophied, and no other lesions could be discovered in the brain or peripheral organs. This case Avould seem to indicate that bilateral disease of the angular gyri will alone suffice to cause complete blindness. Berger has recently recorded two cases of complete blindness with normal or almost normal reaction to light of the pupils and in which extensive softening was found in the occipital lobes. DISEASES OF THE CORTICAL SEXSOEY CENTRES. 291 Nothing is known of disorders of the sense of taste from cortical disease. Treatment. — Inasmuch as anaesthesia and hyperjesthesia are generally associated with other important phenomena such as motor paralysis, the treatment of these symptoms does not require to be specially cfiscussed in this place. In the treatment of neuralgia the first indication is to remove the exciting cause. An endeavor must be made to remove every source of external irritation such as carious teeth, foreign bodies pressino- upon the nerves, cicatrices, tumors, and neuromata. It is manifest that in order to fulfil this indication great scope is afforded the exercise of surgical skill. At other times the exciting cause of a neuralgia is to be found in remote irritation such as when the presence of intestinal worms or uterine disease gives rise to facial neuralgia. Venous conges- tion of the pelvic organs from constipation and portal obstruction is sometimes the cause of sciatica, and in these cases benefit is likely to be obtained from purgatives and the use of natural saline waters like those of Kissingen, Marienbad, and Harrogate. A turpentine enema has also been strongly recommended in such cases. The early stages of neuralgia which arises in rheumatic and gouty subjects must be treated by absolute rest, diaphoresis, the milder counter-irritants, the vapor or Turkish bath, and salicylate of soda or alkalies with colchicum, and by iodide of potassium either alone or in combination with guaiacum, when the acute symptoms have subsided. When the patient is suffering from anpemia, as often occurs in trigeminal neuralgia, large doses of carbonate of iron, with or without cod-liver oil, have a very beneficial effect. In such cases arsenic either alone or combined with iron is a useful remedy, and it is also useful in ophthalmic neuralgia of malarial origin. In malarial neuralgia, however, large and repeated doses of quinine are the most trustworthy remedy and it also may be employed in the treatment of other forms of neuralgia, and is especially useful in trigeminal neuralgia. In neuralgia of syphilitic origin large doses of iodide of potassium must be given, and this drug will also be useful whenever there is reason to suspect the presence of neuritis. Zinc, nitrate of silver, chloride of gold and sodium, and strychnia, are other drugs which have occasionally been found useful in the treatment of neuralgia. Gelse- minum sempervirens, best given in the form of tincture, and croton chloral hydrate, either in one large dose of a scruple or in four grain doses every four hours, have been found useful in the treatment of trigeminal neuralgia, and Dr. Ringer speaks favorably of a liquid extract of tonga prepared by Messrs. Allen k Handbnry, given in drachm doses every four hours. In sciatica, rectified oil of turpentine has been found useful. It is best administered in gelatine capsules each of 292 TKEATMENT. which contains fifteen drops of the oil, and two or three of these may be given at meal-time. Copaiba has succeeded in the hands of Dr. March, of Rochdale. The local treatment of neuralgia consists of the application of hot fomentations and poultices in the early stages, while flying blisters may be applied along the course of the painful nerve when the acute symptoms have subsided. When the nerve is deep-' seated like the sciatic its course may be painted Avith tincture of iodine, or the actual cautery may be used in chronic and obstinate cases. In such cases a very effectual but very severe remedy consists in the sub- cutaneous injection over the seat of severest pain of a few minims of a strong solution of nitrate of silver (gr. x to 5j)- An injection, by means of a subcutaneous syringe, into the substance of tlie nerve of a one per cent, solution of perosmic acid has been favorably reported upon by Eulenburg and others. Ointments containing opium, veratria, aconitia, or equal parts of chloral and camphor, may be rubbed into the skin over the painful nerve, or the course of the nerve may be painted with aconite or belladonna liniment, or rubbed with narcotic and sooth- ing liniments. Chloroform is also found useful as a local application, and its inhalation may be advisable to allay the pain of very violent paroxysms of neuralgia. Chloral and camphor when rubbed together in a mortar form a clear solution Avliich is an excellent local application in neuralgia of superficial nerves. The constant current has been found very successful in the treatment of obstinate neuralgia. /In neuralgia of isolated superficial branches the direction method may be employed and a descending stahilr current passed through the painful nerve. AYhen the polar method is used, the anode is to be placed on the specially painful points and held stationary there, whilst the cathode rests on the back of the neck, sternum, or on any other indifferent part of the body. When the deeper-seated nerves are affected, the anode may be placed on some indifferent part of the body and the cathode over the point of emei'gence of the affected nerve. In order to reach the main divisions of the fifth nerve at the base of the cranium, and after their emergence through the foramen of the sphenoid bone, the current may be conducted transversely through the base of the skull at the appropriate spots, the anode being placed on the painful side. /Benedict recommends that in severe cases of trigeminal neuralgia galvanic currents should be passed longitudinally and trans- versely through the skull, and along the sympathetic nerve. Faradiza- tion occasionally answers better than the constant current, the moist poles being applied to the painful points and along the nerve trunks. The electric hand is sometimes very soothing and agreeable to the patient. DISEASES OF THE CORTICAL SENSORY CENTRES. 293 In the treatment of sciatica the anode should be placed over the sciatic foramen or upon the sacrum, and the cathode upon the specially painful parts. Remak advises that successive portions of the nerve, from six to eight inches in length, should be successively brought under the influence of tlie current, beginning at the sacrum and passing down to the feet. Another method recommended by Remak, under the name of circular current, consists in the stabile application of the anode upon the painful points and over the trunk of the nerve; broad electrodes and strong currents being used. In severe cases Benedict recommends that one electrode should be introduced into the rectum and the other placed over the sacrum, so that the current may pass through the plexus. Ciniselli recommended a zinc and copper plate connected by a wire, to be applied to the aifected limb and worn continuously. In chronic cases I have obtained excellent results by introducing several acupuncture needles over the course of the nerve as it emerges from the sciatic foramen, and passing a feeble galvanic current through them, the positive pole being in contact with the needles and the negative placed over the sacrum. (The faradic current gives the best results when the pain has in great measure disappeared and the subsequent muscular feebleness has to be treated, or if more or less antesthesia be present the faradic brush may be employed. (tnoi'dpr to nft' nrd immediate relief to the pain the administration of narcotics forms an indispensable part of treatment. The most generally effectual narcotic is morphia administered by subcutaneous injection. Another useful method of employing morphia is to dust from one-sixth to one-third of a grain every three or four hours over the raw surface left when the cuticle is removed by the application of a blister over the course of the painful nerve. It may also be useful to change some- times from morphia to stramonium, hyoscyamus, or atropine. In the treatment of epileptiform trigeminal neuralgia Trousseau recom- mended the use of large doses of opium or morphia, and in some cases he prescribed as much as a drachm of morphia, or two or three of opium in the course of the day ; but this treatment ought only to be resorted to -when every other method fills. Large doses of bromide of potassium, either alone or in combination with tincture of opium or chloral, act beneficially sometimes in this form of neuralgia. In intrac- table cases of neuralgia relief for the pain, when all other methods fail, is only to be obtained by means of surgical operations. Resection of the painful nerve, and even amputation of the affected limb, have been resorted to in intractable cases, but such serious operations ought only to be resorted to under the most pressing necessity. Stretching of the affected nerve is a much less serious operation, and several cases of neuralgia 294 TREATMENT. of different nerves are now on record in which the operation has proved successful. Lange procured relief of pain in sciatica by producing forcible flexion of the thigh, and thus stretching the affected nerve over the neck of the femur. The form of plantar neuralgia described by S. Weir Mitchell has hitherto proved intractable to every kind of treatment. The posterior tibial nerve was stretched in one of ray patients by my colleague, Mr. Southam, but the relief which followed was not lasting. Coccygodynia, in addition to the usual remedies, must sometimes be treated by means of a surgical operation. The usual operations are extirpation of the coccyx, and separation of the bone from all the nerves connected with it by means of a tenotomy-knife introduced subcu- taneously. Disorders of the special senses come under the care of the physician as symptoms of other diseases of the nervous system, and the treatment must be directed against the chief lesion, whatever it may be. 'I'he possibility of the sensory affection being of syphilitic origin should never be forgotten. Local electrical treatment is sometimes found useful in those cases in which the acuteness of any of the special senses is diminished. The treatment of those sensory disorders which are caused by disease of the sensory conducting paths and cortical centres, must vary accord- ing to the nature and locality of the lesion. Local treatment is seldom of any use. CHAPTER III. SPASMODIC DISORDERS. The general characteristics of the various forms of spasm have ah-eady been considered and we shall now describe in detail (I.) the spasms which are caused by reflex or direct irritation of the reflex spinal mechanisms and which may be named spino-neural spasms, and (II.) the spasms which are caused by irritation of the cortical motor centres or of the fibres of the pyramidal tracts, and which may be named cereljro- spinal spasms. It is not always possible to make a trenchant division between these two forms of spasm. Some fornas of writer's cramp, for instance, belong probably to the spino-neural, and others to the cerebro- spinal paralyses, and even some local spasms like masticatory spasm may be caused either by reflex irritation or by irritation of the cortex of the brain, but it will be found convenient to describe all forms of these affections in the same place. Notwithstanding the difficulties which present themselves in carrying out this division of spasm, the im- portance of the distinction Avliich underlies the classification must be our justification for adopting it. I. SPINO-NEURAL SPASMS. The spino-neural spasms may be divided into : 1, local spasms affect- ing muscles supplied by particular nerves or their branches ; 2, general spasms caused by excessive irritability of the spinal reflex mechanisms ; and 3, spasms of myopathic origin. Amongst the spino-neural spasms tetanus and tetany are here included, but we are by no means sure that a more extended knowledge of the pathology of these affections will justify their retention in this category. 1. Local Spasms. a. Spasms of the 3Iuscles of the Eyeball. The external muscles of the eyeballs are subject to both tonic an14 SPASMODIC DISORDERS. result from contusions without external abrasion, but is rare after incised wounds. The extent and severity of the wound do not appear to bear any direct relation to the frequency of tetanus, and in some cases the primary wound is healed and forgotten when the symptoms make their api>eai-ance. The interval between the injury and the development of tetanus varies ; the average duration is from four to fourteen days, but the symptoms may begin in a few hours or be delayed many weeks after the injury. Various causes may cooperate with the external wound in the production of tetanus, the most potent of these being exposure to cold and damp after the patient has undergone great excitement and fatigue like that caused l)y a great battle. The absence of antiseptic dressings and other improper treatment seem to increase the liability to tetanus. The most usual cause of idiopathic tetanus is exposure to cold and damp, more especially when the patient is warm and perspiring. It may occur in the course of pleurisy, peritonitis, and other acute diseases. Malaria appears to give rise occasionally to an intermittent tetanus which may be cured by quinine. Strychnine and other toxic agents cause symptoms resembling tetanus. Symptoms. — Premonitory symptoms are generally observed in tetanus, consisting of shivering or a distinct rigor, sensation of dragging in the neck, stiffness in certain muscles, difficulty of articulation and degluti- tion, and yawning. In traumatic cases the wound may become sensitive, and the patient complain of shooting pains radiating from it. These symptoms may occur a few hours or even a few days before the charac- teristic tonic spasms make their appearance. The spasms, as a rule, begin in the muscles of the jaw. At first the jaws can be separated, and the movements of cheAving and swallowing be accomplished, although with difficulty. Soon, however, the jaws become firmly clenched, constituting the condition called trismus ; swallowing of even a small quantity of fluid is difficult and fatiguing owing to spasm of the