6 



Scientific Proceedings (35). 



The present investigation has concerned itself mainly with the 

 water soluble extractive form of sulphur, which besides containing 

 a compound which is either taurin or an immediate precursor of 

 taurin, contains another group of compounds which appear to 

 bear a close resemblance to the group of neutral sulphur com- 

 pounds found in the urine. In view of the fact that Folin con- 

 siders the neutral sulphur of the urine as a measure of tissue 

 metabolism, this observation becomes of special significance. The 

 possibility of comparing the metabolic activity of different tissues 

 with one another, and of the same tissue under different conditions, 

 is at once apparent. 



No very close resemblance can be demonstrated until we know 

 the chemical structure of these compounds. 



The resemblances so far found are as follows : The neutral 

 sulphur compounds of the tissues and of the urine are both soluble 

 in water, soluble in dilute alcohol, not precipitated by phospho- 

 tungstic or tannic acids, precipitated by mercuric acetate. They 

 do not precipitate with barium chloride direct or after boiling with 

 hydrochloric acid. They contain lead blackening sulphur. 



4 (4M) 



The study of autolysis by physico-chemical methods. 

 By ROBERT L. BENSON and H. GIDEON WELLS. 



Further studies of autolytic changes in animal tissues by means 

 of the depression of the freezing point and rise in conductivity show 

 the great value of these methods of estimating the rate and progress 

 of autolysis. The results obtained in this way give a much more 

 accurate and valuable indication of autolytic changes in any given 

 tissue than the commonly used determination of the percentage of 

 nitrogen in coagulable form. Autolysis comprises the disintegra- 

 tion of the cell components and involves a great many substances, 

 some of which are coagulable proteins and many of which are not. 

 If we determine the proportion of nitrogen that is made non-coagu- 

 lable by heat, we get a figure which is the same whether the 

 coagulable nitrogen that has been made incoagulable is in the 

 form of proteoses and peptones, or has been carried to the ultimate 

 amino-acids or even further. The several steps that take place in 

 the autolysis of nucleins also have no effect on this figure after the 



