202 CHEMISTRY OF THE PROTEIDS CHAP. 



products were also obtained from fibrin and from serum-albumin. The 

 alkali-albumose has the composition 



C H N S O 



53-57 7-09 13-62 2'13 23'49 per cent. 



It is Isevo- rotatory, a D = -49 "4. It gives the biuret, the lead- 

 sulphide, and the xantho-proteic reactions, also those of Millon and 

 Molisch, and is precipitated by the alkaloidal reagents. It is in- 

 soluble in water and salt solutions ; readily soluble in acids and 

 alkalies ; soluble in hot alcohol of 50-60 per cent ; insoluble in cold 

 alcohol. The precipitation limits for ammonium sulphate are between 

 18 and 42. It is not digested by trypsin. 



VI. COMPOUNDS FORMED BY MOIST HEAT 



Atmid Albumoses 



The action of steam under pressure on proteids has been investi- 

 gated by Meissner, Krukenberg, Neumeister, 1 and Salkowski 2 (see also 

 p. 92). If fibrin or any other coagulated albumin is placed in a large 

 amount of water, and is heated for one hour in an autoclave to 160, 

 sulphuretted hydrogen and ammonia are given off, while the albumin 

 passes entirely, or for the greater part, into solution ; in the fluid will 

 be found peptones and albumoses. If the solutions which were heated 

 had an acid reaction, Neumeister obtained substances which resembled 

 in every respect Kiihne's peptic-albumoses ; while if the reaction was 

 neutral or alkaline, two new albumoses were formed, which Neumeister 

 called atmid-albumin and atmid-albumose. The behaviour of these 

 two bodies towards acids and towards salts is a very complicated one, 

 probably because these substances do not possess a uniform constitu- 

 tion. Towards precipitants they behave as do the primary albumoses ; 

 they give a violet biuret-reaction and well-marked reactions with the 

 tests of Molisch and Adamkiewicz, but only a slight reaction with 

 Millon's reagent. They do not give the black lead-sulphide reaction, 

 although they still contain traces of sulphur. Their nitrogen-content 

 is low. Both atmid-albumoses are converted by boiling sulphuric acid 

 into deutero - albumoses and peptones, but are attacked only with 

 difficulty by pepsin and trypsin. In all probability they are des-amin- 

 ated albumoses of the anti-group, mixed perhaps with some form of 

 acid-albumin (Cohnheim). 



1 R. Neumeister, Zeitschr. f. Biol. 26. 57 (1890), 36. 420 (1898). 



2 E. Salkowski, action of superheated water on albumin, ibid. 34. 190 (1896), 37- 

 401 (1899 



