PHOSPHORUS FROM CASEINOGEN. 453 



in saline solutions, which it had before purification. It is supposed 

 therefore to be combined with lecithin and to be a lecith-albumin. 

 Since we made no attempt to purify the ovovitellin it may be assumed 

 that the phosphorus, still remaining in an insoluble form, may be 

 contained to a large extent in the lecithin portion of tbe molecule. 

 (Lecithin, being an ester, would not be acted on by trypsin unless lipase 

 were also present. The presence of lipase is, however, very improbable 

 since aqueous extracts of dried trypsin preparations do not possess any 

 lipolytic power. Lipase is generally only obtainable from fresh prepa- 

 rations of pancreas 1 .) If this should be the case, then half of the 

 phosphorus of ovovitellin is combined in the form of lecithin. Lecithin, 

 again, contains only a very small amount of nitrogen. In our experi- 

 ment, the whole of the nitrogen, except about one-ninth, was converted 

 into a soluble form. This result bears out our suggestion that the 

 lecithin portion of the ovovitellin contains about one-half of the total 

 phosphorus. 



DIGESTION OF CASEINOGEN BY ACID AND BY ALKALI. 



It was shown by Langstein (14) that, when albumins were digested 

 by pepsin in 1 per cent, sulphuric acid solution at 37 C. for one year, 

 they were converted to a small extent into ammo-acids. His results 

 were criticised by Salaskin and Kath. Kowalevsky (18) , who sug- 

 gested that the separation of these simple products were due to the 

 action of the 1 per cent, sulphuric acid for the prolonged period of one 

 year. Langstein (15) replied to this criticism and quoted an unpublished 

 experiment by Neuberg on the digestion of gelatine by 1 per cent, 

 acid which confirmed his result. We have made an experiment upon 

 this point and have found that at any rate no soluble P 2 O 5 was sepa- 

 rated in the course of 4 days by 1 per cent. H 2 SO 4 , the figures being 

 8'4 mgm. P 2 O 5 at zero time and 3'5 mgm. P 2 3 after 4 days' digestion. 

 As soon as pepsin was added separation of soluble P 2 5 took place, so 

 that we can in so far confirm Langstein's result. The experiment 

 was not continued, since it was of greater interest to us to determine 

 what strength of acid produced soluble P 2 5 . By employing about 

 15 per cent, hydrochloric acid (equal volumes of HC1 sp. gr. 1*16 and 

 water) we observed a somewhat rapid rate of separation of soluble P 2 3 

 from caseinogen, comparable to that of pepsin. 



1 H. Engel has quite recently found that Bhenania pancreatin "absolut" when 

 extracted with glycerine yields an active lipase. 



