TUMOURS OF THE SKULL-BONES 325 INDEX 335 LIST OF ILLUSTRATIONS FIGS. PAGES 1 and 2. Cranio-cerebral topography 2, 3 3. The cortical motor and sensory areas 8 4 and 5. The scalp-tourniquet 14, 15 6. Cushing’s ‘clips’ 18 7. Hudson’s trephine 20 8. The hand-trephine 21 9 and 10. The technique of trephining 22 11-16. Instruments used in trephining 23, 24 17-19. The formation of an osteoplastic flap 26, 27 20. An occipital cephalocele 33 21. A cephalocele over the anterior fontanelle 35 22. An occipital cephalocele 37 23. A depressed birth-fracture 45 24 A and B. A case of depressed birth-fracture, before and after operation 47 25. To illustrate the effects and position of a birth-hæmorrhage 53 26. The author’s operation for Hydrocephalus internus 64 27. The conversion of Hydrocephalus internus into cephalocele 65 28. Illustrating the lines along which forces received on the vault are transmitted to the base 69 29 A and B. The base of the skull and the base as seen on transillumination 70, 71 30. Plan of the base of the skull 77 31. To illustrate the relation of basic fractures to cranial nerves 81 32-37. The lines pursued by basic fractures 83-8 38 A and B. To illustrate the probable source of profuse hæmorrhage from the ear 97 39. To show the relation of a typical basic fracture to the middle ear and its adjuncts 103 40 and 41. To show the relation of basic fractures to the petrous bone 104, 105 42. A comminuted fracture of the skull 112 43 A and B. An explosive fracture of the vault of the skull 113 44. A temperature chart illustrating the changes in temperature observed in head-injuries 117 45-48. Intermusculo-temporal cerebral decompression 122, 123 49 A and B. The elevation of a depressed fracture of the vault 131 50 A and B.