COMPOSITION OF BRAIN OF ATAXIC PIGEONS 



97 



Also, lipoid-sulphur is in greater amount in the 598-day than in 

 the 205-day brain. In the comparison of the brains of these 

 ages soon to follow (table 5), we shall therefore use the figures 

 obtained for lipoid-phosphorus and lipoid-sulphur (table 6) and 

 ignore the figures for phosphatids and sulphatids which are cal- 

 culated by factor and in terms of per cent of solids. 



The other fractions (protein and extractive) of sulphur and 

 phosphorus may next be considered. They, too, are calculated 

 (table 7) in per cent of total sulphur and of total phosphorus. 



TABLE 6 



Distribution of sulphur and phosphorus in cerebrum and cerebellum-medulla 

 (calculated in per cent of solids) 



Protein-sulphur is present in largest amount in brains 166 and 

 183 days old, and in lowest amount at 205 days. It is lower in 

 the three oldest groups than in the three youngest groups; 11 but 

 the irregularity just noted makes it impossible to use this fraction 

 as an index of age. Extractive-sulphur and total sulphur plainly 

 do not vary consistently with age. 



11 Protein sulphur is lower in both cerebrum and cerebellum-medulla of nor- 

 mals of 598 days than in normals of 205 days. 



