64 SCIENCE PROGRESS. 



O. Nasse introduced the method of boiling proteids 

 with a strong solution of barium hydrate, a method which, 

 elaborated by Schutzenberger, has yielded many valuable 

 results. Nasse 1 discovered that under these circumstances 

 some of the nitrogen was disengaged as ammonia, but that 

 this accounted (in all cases with the exception of gluten) for 

 but a small percentage of the total nitrogen. As a result of 

 his experiments he came to the conclusion that the nitrogen 

 of a proteid is held under different conditions ; some which 

 is readily eliminated by the alkaline earth is in the form of 

 an amide, some is similar to the nitrogen of a creatine group, 

 but the major part, that which is unaffected by this treat- 

 ment, is in the form of an amido-acid. 



Schutzenberger 2 in a series of researches extending 

 over many years has considerably amplified this method. 

 By varying the conditions of temperature and pressure, of 

 amount of barium hydrate employed, and the length of the 

 time of treatment, he has obtained differing results. In his 

 earlier researches he employed coagulated albumin from 

 egg-white which was thoroughly washed with water, alcohol 

 and ether. Weighed amounts of this were treated with 

 quantities of crystalline barium hydrate varying from two 

 to six times its weight, and with water in a closed iron 

 vessel, the whole being heated to temperatures ranging 

 from ioo°C. to 25O C, and during times which varied in 

 different experiments from eight to 1 20 hours. A very 

 large number of such experiments were carried out, and he 

 was able to confirm Nasse's results with regard to the 

 quantity of ammonia given off. Extending his observations 

 he found (i.) that nitrogen to the extent of about 1 per cent, 

 of the total weight of albumin was given off as ammonia 

 by boiling for about half an hour at ordinary pressures ; 

 (ii.) that another 1 per cent, is slowly given off by continued 

 boiling for 120 hours, and that this second result can be 



1 Chem. Centralblatt, p. 137, 1873. And Pfliiger's Archives, vol. vi., 

 p. 589; vol. vii., p. 139; and vol. viii., p. 381, 1872. 



2 Ann. de Chim. el de Physique, 5th series, vol. 16, p. 289 (1879). 

 Comptes Rendus, vol. ioi,p. 1267; vol. 102, p. 289; vol. 106, p. 1407; and 

 vol. 112, p. 189. Bulletin de la Soc. Chun. (1875), ar >d vol. 24. 



