SULPHUR OF THE PROTEINS. 79 



SCHOUBENKO, RuBNER), and a body having the odor of ethyl sulphide 

 (DRECHSEL) have been obtained. 1 



A part of the sulphur separates as potassium or sodium sulphide on 

 boiling with caustic potash or soda, and may be detected by lead acetate 

 and quantitatively determined (FLEITMANN, DANILEWSKY, KRUGER, 

 FR. SCHULZ, OSBORNE, K. MoRNER 2 ) . What remains can be detected 

 only after fusing with potassium nitrate and sodium carbonate and test- 

 ing for sulphates. The ratio between the sulphur split off by alkali 

 and that not split off is different in various proteins. No conclusions can 

 be drawn from this in regard the number of forms of combination which 

 the sulphur has in the protein molecule. As shown by K. MORNER, 

 only about three-fourths of the sulphur in cystine can be split off by 

 alkali, and the same is true for the cystine-yielding complex of the protein 

 substances. If the quantity of lead-blackening sulphur in a protein 

 body be multiplied by f, we obtain the quantity corresponding to the 

 cystine sulphur in the body. By such calculation MORNER found in 

 certain bodies, such as horn substance, seralbumin and serglobulin, 

 that the quantity of cystine sulphur and total sulphur were identical, 

 and therefore we have no reason for considering the sulphur in these 

 bodies as existing in more than one form of combination. In other 

 proteins, such as fibrinogen and ovalbumin, on the contrary, only one- 

 half or one-third of the sulphur appeared as cystine sulphur. 



According to RAIKOW 3 keratin-like proteins split off sulphur dioxide on 

 treatment with phosphoric acid at ordinary temperatures; hence it follows that 

 a part of the sulphur in the proteins, especially in the keratins, exists in direct 

 combination with oxygen and probably combined as in the sulphites. 



The constitution of the protein bodies is still unknown, although 

 the great advances made in the last few years have brought us essentially 

 closer to the elucidation of the question. In studying the constitution 

 of the protein bodies they have been broken up in various ways into 

 simpler portions, and the methods used for this purpose have been of 

 different kinds. In such decompositions, for which proteins have been 

 used that can be prepared in the crystalline form, first large atomic 

 complexes proteoses and peptones are obtained which still have 



1 K. Morner, Zeitschr. f. physiol. Chem., 28, 34, and 42; Patten, ibid., 39; Embden, 

 ibid., 32; Suter, ibid., 20; Friedmann, Hofmeister's Beitrage, 3; Sieber and Schou- 

 benko, Archiv d. sciences biol. de St. Petersbourg, 1; Rubner, Arch. f. Hygiene, 19; 

 Drechsel, Centralbl. f. Physiol., 10, 529; Frankel, Sitzungsber. d. Wien. Akad., 112, 

 II 6, 1903. 



2 Fleitmann, Annal. der Chem. und Pharm., 66; Danilewsky, Zeitschr. f. physiol. 

 Chem., 7; Kriiger's, Pfliiger's Archiv, 34; F. Schulz, Zeitschr. f. physiol. Chem., 25; 

 Osborne, Connecticut Agric. Expt. Station Report 1900; Morner, 1. c. 



3 See Biochem. Centralbl., 4, p. 353. 



