268 DISEASES OF THE BRAIN. 



disease of the brain, if it should have been doubtful, in spite of the 

 duration, severity, and obstinacy of fhe pain. 



Among the local symptoms of tumors of the brain, those of partial 

 irritation (hyperaesthesia, neuralgia, indefinite sensations of formica- 

 tion, twitching, etc.) very frequently precede the partial anaesthesias 

 and partial paralyses, and there are cases of cerebral tumors where 

 these symptoms, and not the headache, open the scene. We have 

 seen that partial symptoms of irritation, occurring in severe structural 

 diseases of the brain, are only to be regarded as secondary effects, and 

 are referable to disturbances of circulation in the vicinity of the affected 

 part. Also that they occur in the most varied diseases, and alone are 

 not pathognomonic of any of them. However, in cerebral tumors, 

 there is one circumstance which is characteristic of the hyperaesthesia, 

 neuralgia, and twitchings, and the anaesthesia and paralysis which 

 usually follow them, namely, that these local symptoms are observed 

 more frequently, even among the cerebral nerves, than in any of the 

 previously-described forms of brain-disease. But we cannot say that 

 symptoms of irritation and paralysis of the cerebro-spinal nerves, such 

 as hemiplegia, etc., are rare, or do not occur; but only that, apart from 

 other symptoms, the occurrence of neuralgia, hyperaesthesia, or anaes- 

 thesia, or of spasms and paralysis in the parts supplied by the cerebral 

 nerves, goes to prove, in doubtful cases, that there is a tumor in the 

 brain. The simple explanation of this peculiarity is as follows : In 

 all the local diseases hitherto treated of, in necrotic softening of the 

 brain, in cerebral haemorrhage, in encephalitis, and its results, the mor- 

 bid process is, with rare exceptions, limited to the brain, and does not 

 attack the nerves passing from it. The case is quite different with 

 tumors, which not only often pass from the brain to the nerves origi- 

 nating from it, but which, in many cases, start from the meninges or 

 skull, and then not unfrequently destroy the cerebral nerves before 

 attacking the brain. Let me call attention to another point, which 

 was first published by my friend Ziemssen, at that time assistant in my 

 clinic. Most paralyses of cerebral nerves are peripheral, when due to 

 tumors, whether these have originated in the brain, or have advanced 

 to the brain from the meninges or cranial bones. On the other hand, 

 most of the few cases of paralyses of cerebral nerves occurring in the 

 other forms of brain-disease are of central origin. Now, it is well 

 known that the state of the nerves and muscles, on electrical irritation, 

 is a certain means of distinguishing central and peripheral paralyses. 

 In central paralysis, the muscle contracts normally when an induced 

 current is passed through the nerve ; in peripheral paralysis, on the 

 contrary, the contraction does not take place. Hence we may thus 

 amplify the above proposition : In cases of local disease of the brain, 





