194: DISEASES OF THE BRAIN. 



The causes of the partial hyperaemia are to be sought for within 

 the skull. Fluxions and congestions result from extravasations of 

 blood, points of softening and inflammation, tumors, and all other dis- 

 eases of the brain that affect the circulation at circumscribed spots. 

 If an artery or a gieat number of capillaries be compressed, or other- 

 wise closed, there is fluxion in the collateral branches ; if, on the other 

 hand, a vein be contracted or closed, there is congestion in the capil- 

 laries supplying it. Of course, there will usually be fluxion at one 

 place, congestion at another, and anaemia at still others, at the same 

 time. But the circumscribed diseases of the brain not only induce 

 hyperaemia by compression of the vessels, but most of them also excite 

 it by irritation of the surrounding parenchyma. Just as we see hyper- 

 aemia and oedema result in the vicinity of tumors, inflammations, ex- 

 travasations of blood, etc., in all other parts of the body, so they also 

 develop in the brain when it is the seat of these diseases. 



On autopsy, it is just as difficult to discover a partial hyperaemia 

 of the brain as it is to make out a general hyperaemia, particularly if 

 the hyperaemia has led to oedema, without the oedema having softened 

 the brain-substance. In some cases, however, in the vicinity of tumors, 

 points of inflammation, etc., we see clearly that the parenchyma is 

 more infiltrated and relaxed, or that there have been small extravasa- 

 tions from the vessels. 



The symptoms of partial hyperaemia of the brain are those of irri- 

 tation and depression, but they are much more limited than the symp- 

 toms of general hyperaemia of the brain, and come under the head of 

 so-called local symptoms (" Herdsymptome," Griesinger). Among 

 these are circumscribed headache, glimmering or sparks before one 

 eye, or blindness of one eye, contraction or dilatation of one pupil, 

 noise or deafness in one ear, neuralgia or anaesthesia limited to one 

 nerve, but especially spasms, contractions, or paralysis, affecting only 

 one-half of the body, one extremity, or a single group of muscles, and, 

 lastly, partial disturbance of the mind. 



The grade and extent of the partial hyperaemia of the brain vary 

 with the greater or less amount of blood contained in the organ, and 

 with the phases and stages of development of the point of disease 

 that they surround. This explains why the local symptoms depending 

 on partial hyperaemia of the brain are sometimes more prominent than 

 at others, or may even disappear and return again. Since, in all severe 

 structural disease of the brain there is complete loss of function of the 

 affected part, whether the trouble there be the development of a tumor, 

 or that the nerve-filaments and ganglion-cells have been broken down 

 or destroyed by an extravasation of blood, the only symptoms that we 

 can consider as immediately due to severe local disease of the brain 



