R. H. Chittenden — Papoid-digestion. 301 



albumin. The so-prepared solution was then poured, with constant 

 stirring, into a comparatively large volume of boiling water acidi- 

 fied with acetic acid. By this treatment the albumin was coagulated 

 in fairly fine flocks, after which it was collected on a cloth filter, 

 washed thoroughly with boiling water and pressed as dry as pos- 

 sible. 



The digestions were carried out as follows: each digestive mix- 

 ture contained 0*5 gram papoid, 10 grams of the moist coagulated 

 egg-albumin, and 25 c. c. of water in which were dissolved the neces- 

 sary amounts of alkali or acid to give the indicated percentages. 

 All the mixtures of the series were placed in a water-bath kept at a 

 temperature of 40-45° C, where they were allowed to stand for 12 

 hours with frequent stirring. At the end of this time, the undi- 

 gested residues were filtered off on weighed filters of pure washed 

 Swedish filter paper, which had been previously dried at 110° C. 

 in suitable weighing bottles. The undigested residues were then 

 washed with hot water until all soluble products were removed, 

 after which they were dried at 110° C. until of constant weight. 



To each digestive mixture was added, likewise, eight drops of an 

 alcoholic solution of thj^mol, in order to prevent possi})le putrefac- 

 tion. 



The 10 grams of moist coagulated egg-albumin used in each 

 digestion contained 1*5 143 grams of dry proteid, as was ascertained 

 by drying a portion at 110° C. until of constant weight. 



The following figures show the results obtained: 



Reaction. 



Weif^ht of 

 undigested residue. 



Coai 

 albumi 



£?ulated 

 n digested. 



Neutral 



0-6503 \ 



^ram. 



57-0 



per cent.* 



0*05 per cent. Hydrochloric acid 



0-6297 



li 



58-4 



( ( 



0-10 " 



0-9060 



( ( 



40-1 



i . 



3-00 " Bicarb, soda 



0-4144 



( ( 



72-6 



it 



400 



0-3896 



( ( 



74-2 



i i 



Without papoid, the above percentages of acid and alkali have 

 little action on coagulated egg-albumin, as is seen from the two 

 following experiments which were carried out exactly like the fore- 

 going, omitting only the papoid. 



Weight of Coagulated 



Reaction. undissolved residue. nlbumin dissolved. 



0*1 per cent. Hydrochloric acid 1'4990 grams. 1-0 per cent. 



4-0 " Bicarb, soda 1-4684 " 3-0 



* Calculated on the amount of dry albumin contained in the 10 grams of moist 

 coagulum. 

 Trans. Conn. Acad., Vol. IX. Decembrr, 1892. 



22 



