TUMORS OF THE BRAIN AND ITS MEMBRANES. 273 



indicates that the tumor is either in one side of the cerebrum (the most 

 frequent seat) or in one crus cerebri, in one side of the pons or in one 

 side of the cerebellum. In tumors of the cerebrum the hemiplegia is 

 usually pure, that is, the other half of the body is entirely free from 

 paralysis. In tumor of one crus cerebri, the paralysis of the opposite 

 side of the body is almost always accompanied by paralysis of the 

 oculo-motor of the same side. In tumors of the lateral portions of the 

 pons, besides the hemiplegia and very common anaesthesia of the oppo- 

 site half of the body, there is usually facial paralysis or anaesthesia of 

 the side of the face corresponding to the tumor. In tumors of the 

 cerebellum, as we have previously shown, hemiplegia is not constant, 

 and when present is not pure, but extends to the other side of the body 

 to a less extent, especially affecting the muscles of the spinal column. 

 Paresis of the muscles inducing bending, erection, and lateral move- 

 ments of the spinal column, first shows itself by a peculiar form of diz- 

 ziness, which we have already fully described, and referred to vibra- 

 tions of the spine in walking and similar acts ; subsequently, it often 

 evinces itself by an utter inability of the body to maintain itself, so 

 in the sitting position the patients collapse and cannot move the body, 

 unless held by both shoulders. Paralysis of both sides results from 

 tumors in both sides of the cerebrum, in the middle parts of the 

 pons and in the medulla oblongata. In the above description of 

 the different symptoms it has already been shown that epi]eptiform 

 convulsions indicate that the tumor is near the cortical substance 

 of the cerebrum ; pain in the back of the head shows that it is in 

 the posterior cranial fossa ; and severe psychical disturbance either 

 indicates numerous tumors in the cortical substance of both hemi- 

 spheres, or that there is secondary meningitis or hydrocephalus. It 

 appears to me that too little attention has been paid to the fact that 

 the intelligence which is at first intact is very much impaired in the 

 later stages of tumors encroaching on the posterior cranial fossa, 

 which impede the escape of blood from the ventricles and induce ex- 

 tensive transudations into them. 



Even on most carefully weighing all the symptoms, many errors 

 occur, and it is very desirable that observers, who have access to a 

 large number of cases, should publish their errors of diagnosis, as well 

 as their successes, more than has hitherto been done. The trust- 

 worthiness of the different aids to the diagnosis and localization of 

 cerebral tumors cannot become perfectly clear till this is done. 



The wide-spread error of designating the various forms of neopla- 

 sia, aneurisms of the brain, and even parasites, by the common name 

 of cerebral tumors, is undoubtedly due to the fact that there are very 

 few cases where the nature of the tumor can be certainly determined 





