THE NERVOUS SYSTEM. 793 



not more than 1 cm. in diameter, and are similar in their appearance, 

 and in the changes subsequent to their formation, to those in the brain. 

 They are usually the result of injury; but may occur spontaneously. 

 These so-called "spontaneous haemorrhages" are undoubtedly in most 

 cases the result of inflammation. They may occur in any acute disease 

 of the cord, and are an especially frequent complication of acute myelitis. 

 Haemorrhage into the cord, occurring in the course of an acute infectious 

 disease, is probably, as a rule, due to an unrecognized myelitis or acute 

 degeneration. Haemorrhages in the course of a chronic myelitis are not 

 common, and are probably due to a softening dependent on interference 

 with nutrition. Haemorrhages into the cord have been reported in syphi- 

 litic myelitis, in syringomyelia, and in tumors of the cord. Gliomata 

 especially are often very vascular, and their thin-walled vessels are sub- 

 ject to rupture. Sometimes, however, haemorrhagic foci are found in 

 the spinal cord without traumatism or evidence of inflammatory change. 

 Larger haemorrhages naturally follow the lines of least resistance, and 

 their long diameter corresponds to that of the cord. To such columnar 

 haemorrhages, usually traumatic in origin, the name hcematomyelia has 



FIG. 519. SECTION OF THE SPINAL CORD SHOWING HEMORRHAGE INTO THE GRAY MATTER AND EX- 

 TENDING LENGTHWISE OF THE CORD. (An early phase of haematomyelopore.) 



This lesion is sometimes called "ha?matoinyella." 



been applied (Fig-. 519). The term is being now more properly used to 

 cover the general subject of haemorrhage into the spinal cord. 



The smaller capillary haemorrhages may be entirely absorbed. They 

 may, on the other hand, form microscopic sclerotic areas. The larger 

 haemorrhages determine a considerable destruction of tissue. They may 

 be absorbed and replaced by fibrous tissue, or the central area may break 

 down into a fluid or semi-fluid mass of blood and tissue, with a more or 

 less definite fibrous wall (Fig. 520). To these columnar cavities or canals 



