ANJ3MIA OF THE BRAIN AND ITS MEMBRANES. 



5. Anaemia of the brain is the necessary result of diminution of the 

 space in the skull by exudations, extravasations, or tumors of the brain 

 and its membranes. Under this form would come a variety which 

 does not belong in our domain, that is, the cases of anaemia which 

 necessarily result from depressed fractures of the skull. We lay pe- 

 culiar stress on the anaemia of the brain resulting from encroachment 

 on the cranial cavity, which is the most frequent form of the disease, 

 because we believe that the so-called symptoms of pressure in apo- 

 plexy, tumors, the various forms of hydrocephalus, and other diseases 

 encroaching on the intercranial space, are not immediately referable 

 to the pressure on the brain-substance, but to the consequent anaemia. 

 Other observers also, amorg them Traube and Leyden^ have recently 

 come to my conclusion. 



Since it is not merely the presence of blood in the vessels of the 

 brain, but the supply of oxygenated arterial blood that is indispensa- 

 ble for the normal functions of the organ, it is evident that, even 

 where the absolute amount of blood in the brain is not diminished, 

 but where its circulation and distribution are changed so that only a 

 small amount of blood enters through the arteries, and but little es- 

 capes through the veins, the same symptoms must arise as in true 

 anaemia. And the experiments of JZussmaul and Tenner entirely con- 

 firm the experience of pathologists, that, in degeneration of the heart 

 from non-compensated valvular obstruction, and in other diseases im- 

 pairing its action, there is an overloading of the veins at the expense 

 of the arteries, and a retardation of the circulation, that is, the same 

 symptoms that occur in anaemia of the brain. 



Lastly, we must mention that, without a diminution of the amount 

 of blood in the brain, and where that fluid is normally distributed in 

 the arteries and veins, symptoms very similar to those of anaemia may 

 result from the blood being too poor in red corpuscles. This symptom 

 also is readily explained, for we are fully justified in considering the 

 red corpuscles as the " bearers of oxygen." Now, if this be so, a dim- 

 inution of red corpuscles will affect the supply of oxygen to the brain, 

 just as a diminution of the blood would. 



ANATOMICAL APPEARANCES. The substance of the brain is dis- 

 colored ; the gray substance appears paler and more resembles the 

 white. The latter is very milky and shining. On section, few if any 

 blood-points are seen on the cut surface. The vessels of the cerebral 

 membranes are empty and collapsed. We do not always find a con- 

 siderable amount of fluid in the subarachnoid space. Kussmaul and 

 Tenner could not prove, on examination, any increase in the cerebro- 

 *pinal fluid which, on theoretical grounds, they had expected to find, 



SYMPTOMS AND COURSE. The symptoms of anaemia of the brain 



