184 THE PROTEIN SUBSTANCES. 



a-guanylic acid is readily soluble, even in cold water, and it is also similar 

 to thymus nucleic acid in other respects. It is precipitated from the 

 solution of its salts by hydrochloric acid but not by acetic acid, and its 

 solutions precipitate proteins. STEUDEL and BRIGL believe that the 

 /3-acid is a potassium salt and that the a-acid is the actual acid, but this 

 view BANG disputes. LEVENE and JACOBS found that the acid con- 

 taminated with alkali does not gelatinize while the pure acid does. The 

 specific rotation of the latter was ()D= 1.27 at 25 C. 



In regard to the preparation of guanylic acid we refer, to the work 

 of BANG, LEVENE and JACOBS. 1 



Thymonucleic Acids. A. NEUMANN has isolated two nucleic acids, 

 a- and jS-thymus nucleic acid, from the thymus gland. The a-acid is 

 soluble with difficulty, and in proper concentration gives a sodium salt 

 which gelatinizes in proper concentration, and a barium salt which is 

 precipitated by barium acetate in substance (KOSTYTSCHEW). The 

 barium salt of the /3-acid is not precipitated by barium acetate. The 

 a-acid is designated as anhydric by SCHMIEDEBERG, 2 and the /3-acid as 

 hydrate, and the first can be transformed into the second by heating. 

 This transformation, according to KOSTYTSCHEW, is a decomposition 

 whereby two-thirds of the purine bases are split off. 



According to SCHMIEDEBERG the thymus nucleic acid is identical 

 with the salmo-micleic acid (from salmon sperm), and also according 

 to STEUDEL probably with the acid from the herring sperm. Other 

 nucleic acids, at least those very closely related to this nucleic acid, have 

 been prepared from the sperm of the burbot (Lota vulgaris) by ALSBERG, 

 of the sturgeon (NOLL) and of the sea-urchin (MATHEWS), also from 

 ox-sperm, brain, spleen (LEVENE), pancreas (LEVENE, v. FURTH and 

 JERUSALEM, STEUDEL), mammary glands and kidneys (LEVENE and MAN- 

 DEL 3 ) and from other organs. 



At the present time we arc not agreed as to the formula for the most 

 carefully studied thymonucleic acids (from the thymus, herring and sal- 

 mon sperms) . According to the numerous analyses of SCHMIEDEBERG and 

 his collaborators for every 4 atoms of phosphorus there occur 14 atoms 

 of nitrogen. The relationship of C to P was 40 to 4 and the relationship of 

 C to N in 12 out of 15 preparations was 40 to 14, and only in 3 prepara- 

 tions 40 to 15. From these facts SCHMIEDEBERG has given the acid 



1 See footnotes 1 and 2, p. 183. 



2 A. Neumann, Arch. f. (Anat. u.) physiol, 1898 and 1899; Kostytschew, Zeitschr, 

 f. physiol. Chem., 39; Schmiedeberg, 1. c. 



3 Alsberg, Arch. f. exp. Path. u. Pharm., 51; Noll, Zeitschr. f. physiol. Chem., 25; 

 Mathews, ibid., 23; v. Fiirth and Jerusalem Hofmeister's Birtrage, 10 and 11; Steudel,. 

 Zeitschr. f. physiol. Chem., 53; Levene and Mandel, ibid., 46, 47. See also footnote 2, 

 p. 179. 



