ANAEMIA OF THE BRAIN AND ITS MEMBRANES. 195 



arc partial anaesthesia, partial paralysis, and the loss of certain mental 

 functions. 



If, in the course of an apoplexy, of an abscess of the brain, or of a 

 cerebral tumor, etc., we have symptoms of partial irritation, as well as 

 those of partial paralysis, the former cannot possibly depend on the 

 disease itself, but must be due to the anomalies of circulation in its 

 vicinity. Moreover, all temporary symptoms of paralysis occurring in 

 the course of local destructive diseases do not depend on the disease 

 itself, but mostly on the disturbances of circulation around it. (When 

 speaking of diseases encroaching on the space in the skull, we shall 

 show that temporary paralysis may also result in other ways.) The 

 fact that in apoplexies, tumors, abscesses, etc., where complete or 

 even partial restitutio ad integrum is not conceivable, paralysis not 

 unfrequently decreases or entirely disappears, seems at first difficult to 

 explain, but the explanation is simple when we bear in mind that the 

 symptoms of paralysis may depend on a collateral oedema in the vi- 

 cinity of the disease, and that the extent of this oedema varies greatly. 



Lastly, the most varied diseases of the brain would induce the 

 same symptoms, if they had similar locations and extent, if the dis- 

 turbances of circulation in the vicinity of the different diseases did not 

 vary. But the disturbances of circulation in the vicinity of a tumoi 

 are different from those in the vicinity of an abscess, and these again 

 differ from those about a portion of brain broken down by an extrava- 

 sation of blood. This, to some degree, explains the difference of 

 symptoms in different diseases of the brain that have the same seat 

 and extent. 



The treatment of partial hyperaemia is to be conducted on the same 

 plan as that for general hyperaemia of the brain. If we lessen the 

 supply of blood, or facilitate its escape, we moderate the local fluxion 

 or congestion. 



CHAPTER III. 



ANEMIA OF THE BRAIN AND ITS MEMBRANES. 



ETIOLOGY. For a time the possibility of anaemia ot the brain was 

 denied, just as that of hyperaemia was, and on the same grounds which 

 were given in the first chapter. We have already called attention to 

 the errors in these conclusions, and shall only mention here that, inde- 

 pendently of the numerous autopsies where the brain has been found 

 anaemic, Donders^ Kussmaul and Tenner have observed excessive 

 anaemia through an opening (covered by a glass plate) in the skull of 

 living animals. 



The causes of anaemia of the brain are 



