5. Later after-results--insomnia, restlessness, impairment of memory, aphasia, and hemiplegia--all of which are dependent either on rough handling of the brain or lighter handling of an already diseased brain. [69] _Lancet_, November 27, 1909. [70] Purves Stewart, _Brit. Med. Journ._, June 11, 1910, p. 848. [71] Frazier, _Univ. of Philadelphia Bulletin_, April 1909. [72] _Berlin. Klin. Wochenschrift_, No. 3, 1908. [73] _Brit. Med. Journ._, June 11, 1910. [74] Frazier, _Univ. of Philadelphia Bulletin_, April 1909. [75] _A System of Operative Surgery_, vol. i, p. 437. [76] _Univ. of Pennsylvania Medical Bulletin_, April 1909. CHAPTER XI TUMOURS OF THE SKULL-BONES In this the last chapter of this work, I originally intended to deal with tumours of the scalp and skull-bones. With respect to tumours of the scalp there is, however, but little to say. The various conditions are well recognized, their pathology is known, and there is in general but little to relate. Tumours of the skull-bones come under a different category and require some consideration. =Tumours of the skull-bones.= The more important of these tumours are as follows:-- Osteomata. Sarcomata, primary and traumatic. Secondary sarcomata and carcinomata. OSTEOMATA Exostoses of the skull, though by no means of frequent occurrence, occupy such definite positions that it would appear as if they were dependent on some local governing cause. They develop most frequently in the following positions:-- At the external angular frontal process. At the frontal and parietal eminences. In the region of the frontal sinus. In the region of the external auditory meatus and mastoid process. All pathological museums possess specimens illustrating the formation of such exostoses, tumours of a like nature in other parts of the skull being excessively rare. In endeavouring to arrive at an explanation it would appear necessary to direct one’s attention to tumours of a similar nature occurring in other parts of the body, more especially in the long bones. There, it is well recognized that their development is dependent on irregularities of growth in the region of the epiphyseal lines, regions where activity of growth is long maintained. On referring again to the skull, similar features appear. For instance, the frontal bone, besides possessing one primary centre for the frontal eminence, has secondary centres for the external angular frontal process, for the trochlear fossa, and for the nasal spine, and it is highly probable that those exostoses which develop in the region of the frontal sinus in reality arise from one or other of the secondary centres situated in that region. [Illustration: FIG. 92. IVORY EXOSTOSES OF THE SKULL.] Both frontal and parietal eminences are also sites of active and prolonged ossification, and the tumours there arising are to be explained on a like hypothesis.