— 201 — 



per cent of the total phosphorus of the brain, 35.8 per cent are 

 soluble in the main research. Hence we see that the ferments 

 are able to solubilise 11.8 per cent of the total phosphorus of 

 the brain during 96 hours of incubation at 37". 



Table VII! (pag. 204) shows that during 96 hours of 

 incubation o f the brain a t 37° the ferments are 

 able to solubilise 15.9 per cent of the in soluble 

 phosphorus e o n t e n t . 



A part of this excess of phosphorus arises, doubtless, from 

 the disintegration of the phosphatides , a fact which has al- 

 so been sliown up by Simon , who found that after 72 hours 

 incubation,. at 38^' - 40°, of calf brain: 38.78% of the total pho- 

 sphorus of the fresh brain are soluble in main research and only 

 22.21 °/o in control research. Therefore, he found in the main- 

 research an iiicrease of 16.5 per cent of the total phosphorus of 

 calf brain , due to the action of the ferments. 



Througli the action of the nuclease upon the nucleic acid, 

 phosphoric acid is freed 



Nuclease. 



The experiments already described show that in the filtrate 

 of the control research the presence of free purin bases were 

 not observed ; in that of the main research , on tlie contrary, 

 they were constantly present. 



It is evident that, during autolysis the nucleo-pro- 

 teid of the brain is split up by a proteolytic fer- 

 ment and the freed nucleic acid is further disin- 

 tegrated by the nuclease which in its turn sets 

 free t h e p h o s p h o r i e acid and t li e puri n-b a s e s . 



The presence of the latter may be proved by precipitation 

 with ammoniacal Silver nitrate. This precipitable form of the pu- 

 rin-bases was called " manifest „ by Salkowski. 



The purine nitrogen contents estimated in the filtrates A, in 

 ali experiments, are summarized in table VII. 



