British Association. 393 



remark is more truly applicable, than it is to diseases of the brain, 

 and its investing membranes. Nobody is less disposed than myself 

 to estimate, at a low rate, the value of information obtained through 

 the medium of researches, similar to those of Sir Charles Bell, Drs. 

 Abercrombie, Bright, Hodgkin, Sims, and others in this country ; 

 and of M. M. Rostan, Foville, and many others on the continent. 

 Knowledge of the precise nature of morbid changes has its value, 

 even in a practical point of view, if not by directing us always to 

 remedies, at least, by making us aware what we are to expect in 

 particular cases, as the final results of disease, and as pointing out 

 the limits of what is possible, or what ought to be attempted with 

 reference to cure. Still we ought not to lose sight of the fact, that 

 the recovery of patients, and not merely accurate pathology and 

 diagnosis, is the ultimate object. 



Perhaps all curative attempts in cases of disease affecting the brain, 

 resolve themselves into the modifications which medical art is capable 

 of effecting in the vascular state, of parts within the skull. We 

 can promote by various means either fullness or inanition of the 

 blood vessels in the brain. Whether anything beyond this is in our 

 power is very uncertain. Besides general and local bleeding, all 

 those means belong to the same class, which act by refrigerating or 

 heating the surfaces either of the head or of other parts. Refrigerant 

 applications to the head have the effect of contracting the calibre of 

 the arteries, and thereby diminishing the quantity of their contents. 

 Pediluvia, or other means of applying warmth to the lower extremi- 

 ties, produce a similar result by augmenting the capacity of vessels 

 remote from the head, and causing a greater quantity of blood to be 

 determined into them. All these means plainly owe their efficacy, 

 to the modification which they bring about in the state of the vascular 

 system of the brain. The only class of remedies respecting the 

 " modus operandi" of which, any question can be raised, is those 

 which produce what is termed counter-irritation, and perhaps the 

 doubt which exists in this instance, arises from the obscurity of the 

 subject. It is generally supposed, and perhaps correctly, at least, it 

 is very difficult to find any other hypothesis on the subject that is 

 more probable, that the means of counter-irritation, such as rube- 

 facients, vesicatories, and issues, produce their effect by lessening a 

 hyperplethoric state of the vessels in internal parts, and that they 

 bring this to pass by increasing the fullness of the vessels in surfaces 

 to which they are immediately applied. There are facts which it is 

 very difficult to reduce under this sort of explanation, as for example, 

 the relief obtained in cases of pneumonia or of bronchitis, by means 

 of blisters applied to the parietes of the chest, there being in these 

 instances no continuity of structure that might render the proposed 

 explanation in some degree intelligible. On the other hand, there is 

 little doubt that such remedies are most efficacious when they are 

 applied over surfaces nearly in juxta-position with the seat of disease, 

 and this fact, if not called in question, goes far towards establishing 

 the notion before alluded to, as to their mode of operation. 



As the means which are within our reach for treating disorders of 

 the encephalon are so circumscribed, it appears so much the more 

 necessary, to endeavour to a])ply in the most efficacious manner such 



