98 MATHILDE L. KOCH AND OSCAR RIDDLE 



Protein-phosphorus decreases wholly consistently with age in 

 all of the normals. Extractive-phosphorus decreases progres- 

 sively with age. This rule fails, however, in the very old (2,021- 

 day) brain. Total phosphorus also progressively decreases with 

 age. 



In the comparison of the normal and ataxic brains, the younger 

 age is characterized, therefore, by higher values for water, pro- 

 tein, protein-phosphorus, extractive-phosphorus, and total phos- 

 phorus; and by lower values for lipoids, cholesterol, lipoid-phos- 

 phorus, and lipoid-sulphur. A comparison, on the basis of these 

 nine constituents, of corresponding parts of the brain of normals 

 and ataxics will be made first. That of the whole brain of all of 

 the normals and ataxics can be better done later. 



Results of analysis of cerebrum and cerebellum-medulla of normals 



and ataxics (table 5) 



The cerebrum of the younger (less) ataxic group gave lower 

 figures for moisture, protein (extractives), 12 cholesterol, lipoid- 

 sulphur, and lipoid-phosphorus than the younger normals with 

 which they should be compared. Higher figures were obtained 

 for lipoids, protein-phosphorus, extractive-phosphorus, and total 

 phosphorus. Six of these figures indicate that the cerebrum of 

 the younger ataxics (206 days) were less differentiated than those 

 of the younger normals (205 days); three figures point to the 

 opposite conclusion. 



The cerebellum-medulla of the younger ataxics show smaller 

 values for lipoid-sulphur, protein-phosphorus, lipoid-phosphorus 

 (phosphatids, sulphatids, extractives), and total phosphorus; 

 greater values for moisture, protein, lipoids, and extractive-phos- 

 phorus. Five of these figures point to the (less) ataxic cerebel- 

 lum-medulla as the younger stage, while three are opposed. 

 Cholesterol shows no difference. Summarizing this comparison 

 of parts of the brain of younger normals and younger (less) atax- 

 ics, it may be said that the results show but little of chemical 



'- Substances which are not really distinctive of age will sometimes be 

 included in the summaries or comparisons which follow, but to distinguish them 

 they will be included in parentheses. 



