450 



R. H. A. PLIMMER AND W. M. BAYLTSS. 



most satisfactory, since, as is shown below, the soluble P 2 O 5 consists 

 only to a very small extent of inorganic phosphoric acid. 



THE ACTION OF PAPAIN ON CASEINOGEN. 



Of recent years a great many investigations have been made upon 

 the digestion of various albumins by papain. The most recent observers, 

 Chittenden, Mendel, Harlay, all seem to agree that leucine, 

 tryptophane, and tyrosine, the typical products of a tryptic digest, are 

 not formed, but the various statements with regard to the medium in 

 which papain exerts its greatest effect are very contradictory. Mendel 

 and Underbill (17) , in 1.901. found that papain acted both in acid and 

 alkaline media, the most favourable being 1 per cent. NaHC0 3 or 0'5 

 per cent. Na^OOs, but as to the actual extent and the rate of action of 

 papain no experiments have as yet been made. 



Our experiments have been carried out in precisely the same way 

 as described above : we have determined not only the soluble P 2 O a but 

 also the soluble nitrogen, so that a better idea of the actual change which 

 occurred might be obtained. The results are best seen from the 

 experimental data : 



50 grs. caseinogen dissolved in 2070 c.c. water + 30 c.c. y- NaOH and divided into three 

 portions : 



