256 COMPARATIVE PHYSIOLOGY OF THE BRAIN 



in certain forms, and it seems to be pretty generally 

 true that the formation of solid cell-walls becomes 

 impossible under such conditions (11). It is possible 

 that in the case of lack of oxygen, physical changes 

 in the state of certain constituents of the brain are 

 prevented which are necessary for the activity of 

 memory. 



Some physiologists seem to be of the opinion that 

 when the brain contains a good deal of blood the 

 body has a special feeling of happiness. I recall a 

 popular lecture by a prominent psychiatrist in which 

 he maintains that when the cerebral hemispheres con- 

 tain a great deal of blood the proprietor of this brain 

 enjoys the absolute happiness (?) of an intoxication 

 from champagne. This psychiatrist evidently ima- 

 gines that the greater the supply of blood is, the 

 better the brain is nourished, and that with the in- 

 creasing nourishment of the brain the feeling of 

 happiness increases. Among the food-substances 

 which are offered to the brain in large quantities by 

 the dilatation of the arteries oxygen takes the first 

 place. It was formerly assumed that the oxygen- 

 supply determined the metabolism, but we now know 

 definitely that internal processes in the tissues 

 determine the consumption of oxygen, probably 

 processes of fermentation. If a certain quantity of 

 oxygen is present in the brain, the superfluous oxygen 

 has no effect. The same is probably true of all the 

 other food-constituents. Under normal conditions 

 the oxygen-supply in the brain is sufficient as long as 



