A NEW DEPARTURE IN NEUROLOGY 65 



system, along the lines of least resistance, which are here 

 those in continuity with the inter-meningeal spaces, along 

 the nerve trunks, fibres, and terminals. 



In this way we attain a clearer view of the etiology and 

 pathology of many diseases and morbid phenomena, such 

 as that of metastasis, which no other means with which I am 

 familiar will enable us to do. I, therefore, in all seriousness 

 claim for the practical outcome of the manner and method 

 of cerebro-spinal fluid circulation and excretion, as an aid 

 to diagnosis and treatment, a position of great importance. 



This claim would be incomplete, however, without a 

 brief consideration of the subject of cerebro-spinal fluid 

 excretion and the nature of the excretory mechanisms. 



Secreted and circulated in the manner shortly described 

 above, the cerebro-spinal fluid is brought into contact, more 

 or less intimate, with every structure of the nervous system, 

 central and peripheral, and is constantly liable to move- 

 ment and displacement during its progress from its source 

 in the pia mater proper and its choroid inflexions, therefore 

 it must necessarily carry in solution, or suspension, whatever 

 nervine material is shed into it during its intra-neural flow, 

 and thus requires the provision of outfall facilities to enable 

 it to dispose of these effete materials, and thereby, also, to 

 be the means of mechanically relieving, when necessary, 

 over intra-cranial and intra-spinal pressure. 



The great central organ, the brain, must, from this point 

 of view, be the structure discharging the greatest propor- 

 tion of disintegrated and effete material into the cerebro- 

 spinal fluid, and hence must be safeguarded to a 

 proportionately great extent ; and this is found to be the 

 case, for here we find means of escape provided to secure 

 drainage under all possible combinations of circulatory 

 circumstances. 



Thus, at the anterior aspect of the forebrain we have 

 two great channels of drainage laid down from the lateral 

 ventricles through the olfactory tracts, bulbs, nerves, and 

 Schneiderian mucosa, with subsidiary connections with the 

 sub-arachnoid and sub-dural spaces, and always more or less 

 engaged in the work of physiological evacuation. 



From the central, or mid-brain, a most elaborate system 

 of drainage is effected from the third ventricle, through the 



