Sulphur Compounds in Brain Tissue. 



5 



and to the action of cobra venom will play a role in the final solu- 

 tion, but my own experiments have not hitherto thrown any light 

 on the subject. 



As regards the method, the blood is to be drawn into 2 per 

 cent, sodium citrate, thoroughly washed, and made up into a 4 per 

 cent, suspension in 0.9 per cent, common salt. The suspensions 

 may be tested at once, or may be kept in the ice box until the fol- 

 lowing day and then tested. Equal quantities of a 1 : 8,000, and of a 

 1 : 1 5,000 dilution of cobra venom are then added, and after one hour 

 incubation the results may be read. If still higher dilutions, as from 

 10,000 to 60,000 are used, the cells must be incubated for one hour 

 and observed the next morning, but nothing is gained by this except 

 more delicate gradations. Syphilitic cells should resist a solution 

 twice as strong (1 : 8,000) as that which is sufficient to destroy all 

 the control (1 : 15,000). If intermediate solutions are also used, it 

 is possible to trace the gradual loss of the reaction in treated cases. 

 It is probable that each specimen of cobra venom would have to 

 be independently standardized, but one gram would then suffice 

 for about 5,000 tests. 



3 (413) 



The distribution of sulphur compounds in brain tissue. 



By W. KOCH and F. W. UPSON. 



\_Froni the Hull Physiological Laboratory of the University of 



Chicago.!^ 



The distribution of sulphur expressed in per cent, of total among 

 the various chemical groups of the whole brain is approximately 

 as follows : (1) Proteins, 60 per cent. ; (2) lipoids, 26 per cent. ; 

 (3) water, soluble extractions or neutral sulphur compounds, 9 

 per cent. ; (4) sulphates, 5 per cent. (Total sulphur in per cent, 

 of dry matter is from 0.45 to 0.5.) 



Sulphur occurs in the following five stages of oxydation : (1) 

 Cystein R — S — H, (2) cystin R — S — S — R, (3) sulphonate or 

 taurin-like R — S0 2 — OH, (4) ethereal (RO) 2 S0 2 , (5) sulphates. 



Taking the various groups of chemical constituents, the follow- 

 ing stages of oxydation of sulphur have been found in each : Pro- 

 tein — (1) cystein, (2) cystin, (3) ethereal ; lipoids — (4) ethereal. 

 Water soluble extractives (1 or 2 or both) most likely cystein, (3) 

 sulphonate or taurin-like. 



