RESULTS OF ANALYSIS 63 



THE RESULTS OF THE ANALYSIS. 

 A. 



Inspection of the results of analysis, which are tabulated on pages 

 111-130, shows that there is a considerable deficit in the sum of the 

 units composing the protein molecule. 



The best analyses are those of the protamines, of the silk-fibroin of 

 spider's silk, and the gliadin of wheat ; in these, some 80-90 per cent, 

 of the protein is accounted for ; in most cases, the sum of the figures 

 only reaches 50-70 per cent, and in the other cases complete analyses 

 do not exist. The deficiencies are due almost entirely to losses in- 

 curred in isolating and purifying the amino acids. 



A careful inquiry where the loss occurs has been made by Osborne 

 in conjunction with Leavenworth and Brautlecht [1908] and in con- 

 junction with Jones [1910, I, 3], and by Abderhalden [1910], Abder- 

 halden and Weil [1911, 2; 1912, I ], who have estimated the nitrogen 

 at each stage in the process for isolating the mono-amino acids. 



Osborne, Leavenworth and Brautlecht have proved that the loss 

 does not fall upon the di-amino acids. They are convinced that the 

 method for their isolation and estimation is extremely satisfactory, for 

 they have been able to recover from 80-90 per cent, of the di-amino 

 acids in a pure state. They consider that no other di-amino acid than 

 the three hexone bases is present in most proteins ; Fischer and 

 Abderhalden's diaminotrioxydodecanic acid in caseinogen may be an 

 exception ; this protein seems to be the most complex in the number 

 of units which it contains. 



The loss therefore occurs in the isolation and estimation of the 

 mono-amino acids. Fischer pointed out, when he first described his 

 ester method, that the values were not to be regarded as quantitative. 

 The fact that all the figures given are those of the amount of the pure 

 dry compound isolated is sufficient evidence that the total quantity of 

 products is not accounted for. 



The sources of loss in the several steps of the long process have re- 

 ceived special attention from Osborne and Jones [1910, I, 3], who are 

 confirmed in their observations by Abderhalden and Weil [1911, 2 ; 

 1912, I]. 



I. Hydrolysis. In many cases the hydrolysis of the proteins may 

 not have been complete. Some proteins are very difficult to bring 

 into solution in the concentrated hydrochloric acid, and portions may 



