556 APPENDIX. 



a~id, a mean quantity of cholesterin, and an excess of the other 

 salts. 



The white substance contains more cerebric acid and cholesterin 

 than the grey, and consequently less of the other fats. 



Although all these constituents of the brain-fat are found in the 

 smaller mammals as well as in birds, amphibians, and fishes, and 

 likewise in young infants and in the embryo, yet the quantity of 

 cerebric acid seems to diminish as we descend the animal scale, 

 and to be smaller in the infant and foetus than in the adult. 



III. His examination of the water-extract was not very satis- 

 factory. He found 



1. That the water-extract of the brain both of man and other 

 mammals was entirely devoid of all those crystallisable bodies 

 which have as yet been found in other parts of the organism. 



2. That lactic acid was certainly present, and probably also 

 another non-volatile acid, in addition to volatile acids. 



3. That, besides albumen coagulable by heat, there were pre- 

 sent various modifications of albuminous substances which were 

 not precipitated from their solutions by boiling ; and that at least 

 two nitrogenous substances were present, one of which was soluble 

 in water alone, the other in water and alcohol. 



IV. From a large number of analyses of the mineral constitu- 

 ents of the brain he deduces the following conclusions : 



1. The inorganic constituents of the cerebral substance are the 

 same as we meet with in other organs and in the formative fluids. 



2. This qualitative condition holds good in all the classes of 

 the vertebrata. 



3. The ratio of the potash to the soda is nearly intermediate 

 between the ratios occurring in the ashes of flesh and blood re- 

 spectively. 



4. Sulphates are almost entirely absent, and the quantity of 

 the chlorine is very variable. 



5. In man and other mammals the medulla oblongata contains 

 more earthy phosphates than the other parts of the brain. 



6. The amount of inorganic constituents is greater in the brain 

 of birds than in that of man or other mammals. 



7. The brains of amphibians and fishes contain more inorganic 

 constituents than those of the other classes of animals. 



8. The amount of earthy phosphates is moreover greater in 

 the brains of amphibians and fishes than in the other classes of 

 animals. 



