THE DECOMPOSITION PRODUCTS OF PROTEIDS. 31 



elimination, in such a way that the first amount of ammonia might be 

 considered to come from one of the amide radicles of the oxamide, while 

 the second corresponded to the urea, and the third to the remaining 

 nitrogen of the oxarnide, then present as oxamic acid. 



After precipitating the barium with carbonic anhydride and sulphuric 

 acid, he obtained, by distillation in a partial vacuum, a small quantity of 

 acetic acid, traces of formic acid, and an essential volatile oil which he 

 indentified as pyrrol contaminated with smaller quantities of methyl- 

 pyrrol and ethyl-pyrrol. The remainder, which did not volatilise 

 nor sublime at a low temperature, he termed rfeidu fixe. By con- 

 trasting the composition of this with that of the original albumin, 

 and taking into account the substances already enumerated, he found 

 that the essential action of the barium hydrate was that of 

 hydrolysis. By repeated crystallisations from water, alcohol, and 

 ether, he separated the constituents of his rdsidu fixe and found 

 they were amido-acids of two classes, which we may term A and B. 



A. These comprised over 80 per cent, of the total weight ; in them 

 the proportion N:0 = 1:2. They consisted of 



1. Amido-acids of the series C n H 2n+1 N0 2 . 



These he called Icucines. They included alanine (0 = 3) in small 

 quantities, propalanine or amidobutyric acid (0 = 4), butalanine or 

 amidovaleric acid (C = 5), both in considerable amount, and leucine or 

 amidocaproic acid (C = 6), in very large quantities. Glycocine or amido- 

 acetic acid (0 = 2) was not found. 



2. Amido-acids of the series C n H 2n _ 1 N 2 0. 



These are amido-acids of the acrylic series, and were called leuceines. 

 Here, too, the term which was most abundant is that in which = 6, but 

 bodies corresponding to C = 4 or 5 were also found. 



3. Amido-acids of the series C n H 2n N 2 4 , or some multiple of this. 

 To these substances he gave the name of gluco-proteins, on account 

 of their sweet taste. The most abundant of these were those in which 

 C = 9 or 7, or some multiple of these numbers ; but others in which 

 8, 10, and 11 were also isolated. 



B. These comprised about 16 per cent, of the total weight; in them 

 the proportion N:0 = 1:3, or 1:4, or 2:5. In this class were found 



1. Tyrosine ; the amount of this was about 3'5 per cent. 



2. Tyroleucine, C 7 H n N0 2 , in about the same quantity. 



3. Very small quantities of glutaminic acid, C 5 H 9 N0 4 . This is an 

 optically inactive amido-derivative of one of the pyrotartaric acids 

 (glutaric). 



Of these substances, Schiitzenberger found varying quantities, 

 according to the degree to which the hydrolytic decomposition had been 

 carried out. The more thorough the hydrolysation, the more leucines 

 and leuceines were found ; but in earlier stages gluco-proteins were 

 in excess. 



With other proteids he obtained corresponding results. Gelatin 

 gave the same substances, with the addition of amido-acetic acid or 

 glycocine ; 20 to 25 per cent, of this substance was obtained. 



He concluded that the albumin molecule, under the action of barium 

 hydrate, loses ammonia, carbonic anhydride, acetic and oxalic acid, and, 

 becoming hydrated, forms in the first instance gluco-proteins, mainly 

 those in which 0=9, or some multiple of this, and that on further action 

 these are changed into leucines and leuceines. 



