42 CHEMICAL PHYSIOLOGY. 



Much, of it is contained in the brain in a state of such 

 firm combination that even concentrated sulphuric acid 

 does not easily set it free. There is further in the brain 

 cholesterme, the peculiar alcohol of which a quantity 

 is constantly excreted with the bile. The albuminous 

 substance of the brain has not yet been isolated com- 

 pletely ; a small quantity can be extracted as potash- 

 mfooiisinat"" albumen (or caseine) ; another quantity is insoluble in 

 water, and its presence can only be deduced from the 

 curdling of brain-matter by boiling, and 'from the pro- 

 ducts of the chemolytic process, which, as I have found 

 by special researches, yields all the products of chemo- 

 lysis of albuminous matter, volatile acids and alkalies, 

 leucine, tyrosine, and other substances. Of other 



Various in- J 



gredients. matters there are found in the brain substance lactic 

 and a volatile acid, and inosite; uric acid, xanthine 

 and hypoxanthine ; kreatine. Sugar is sometimes 

 found, but may be merely a product of transformation 

 of cerebrine, and more rarely a substance which gives 

 reactions similar to starch, and the study of which 

 may perhaps throw some light on the peculiar disease 

 termed amyloid degeneration. In diseases, leucine and 

 a homologue of it appear sometimes. In others much 

 urea collects in the brain and in the cerebro-spinal 

 fluid, which fills the cavities of the brain and spinal 

 marrow. The largest quantities of urea are met with 

 in cholera, in which the cerebro-spinal fluid may con- 

 tain as much as ordinary urine. In a case of softening 

 of the brain Lehmann found glycero-phosphoric acid 

 in the softened matter. The brain substance con- 

 tains 25 per cent, of solids only, and 75 per cent. 



