100 Profs. A. Gamgee and W. Jones. 



-"On the Optical Activity of the Nucleic Acid of the Thymus 

 Gland." By ARTHUR GAMGEE, M.D., LL.D., F.E.S., Emeritus 

 Professor of Physiology in the Owens College, Victoria 

 University, and WALTER JONES, Ph.D., Associate Professor of 

 Physiological Chemistry in the Johns Hopkins University. 

 Received May 15, Read May 28, 1903. 



We have lately shown* the dextrorotatory character of the nucleo- 

 proteids of the pancreas, thymus, and suprarenal gland. We have, in the 

 course of our investigations, shown that the "nucleins " possess a stronger 

 rotation than the " nucleoproteids " properly so called, and from which 

 they are derived, and in the researches which we have planned, and 

 which naturally are suggested by our previous work, the first step 

 appeared to us to be to determine the optical activity of the nucleic 

 acids corresponding to the nucleoproteids investigated by us. 



In the present paper we shall confine our attention to the optical 

 -activity of thymus-nucleic acid, prepared by the method of Kossel and 

 Neumann.! We adhered closely to the method recommended by these 

 chemists, which furnishes with great ease a colourless product, yielding 

 colourless and perfectly transparent solutions admirably adapted for 

 polarimetric observations. From 6 kilogrammes of trimmed thymus 

 Kossel and Neumann obtained 120 grammes of pure nucleic acid. 

 From 600 grammes of the gland we obtained 9 -5 grammes, though no 

 special pains were taken to work even in an approximately quantitative 

 manner. Our purified product, like that of Kossel and Neumann, was 

 free from proteid and barium. 



1. An amount of nucleic acid weighing 1-109 grammes was sus- 

 pended in water and dissolved by the cautious addition of dilute 

 solution of ammonia in small quantities, so that when solution had 

 been effected the reaction of the solution towards litmus was neutral, 

 The volume of the solution was made up to 100 c.c. and it was then 

 -examined polarimetrically. 



Weight of substance ( W) 1 1 09 grammes. 



Volume of solution (V) 100 c.c. 



Length of tube (L) 200 m.m. 



Observed angle (a) +3 29'. 



MD = + 156-9. 

 2. 10 c.c. of the above neutral solution were diluted with 10 c.c. 



* Gamgee and Jones, " On tlie Nucleoproteids of the Pancreas, Thymus, and 

 Suprarenal Gland, with especial Keference to their Optical Activity," ' Rov Soc. 

 Proc.,' vol. 71 (1903), p. 385. 



t Kossel and Neumann, ' Ber. d. Deutsch. Chem. Ges.,' vol. 27, p. 2215. 



