345 
1910-11.] Small Degrees of Enzymatic Peptolysis. 
curve may be considered a straight line and the reading directly proportional 
to the concentration o£ tyrosin. 
A series of digestions were now carried out in order to discover if the 
quantity of tyrosin produced by the same proportions of enzyme and 
substrate under standard conditions were constant. For this purpose it 
seemed advisable to use an enzymatic preparation whose properties were 
fairly well known, and which could be obtained in reasonably large 
quantities. It was therefore decided to use the preparation known as 
Armour’s Pancreatin. 
Seven series of digestions in all were carried out. In each series the 
digestions were carried out simultaneously, using the same aipount of 
enzyme and substrate. The quantity of pancreatin used was either 
•05 gm. or T gm., the time of digestion being varied in the different series. 
The following results were obtained : — 
(1) 8-0, 8*0, 8-0, 8-4, 8-2, 8‘0, 8*0. 
(2) 5*8, 5 6, 5-6, 5-6, 5-4, 5-4, 5*4, 5-4, 5-6. 
(3) 7*4, 7-2, 7-3, 7*2, 7*6, 7-4, 7-4, 7*4, 7-6. 
(4) 8-0, 8-0, 7-8, 8-0, 8-2, 8-2. 
• (5) 7*2, 7-0, 7-4, 7-4, 7‘4, 7*0, 7*2. 
(6) 8-0, 8*0, 8-4, 8-2, 8-4, 8*2, 8-4. 
(7) 4-0, 4-2, 4-4, 4-0, 4*0, 4-0. 
In carrying out the method the following materials are required : — 
1. Pepton . — The solution used in these experiments has been of 20 per 
cent, strength. As this solution usually gives an acid reaction, sodium 
bicarbonate should be added till neutral. The pepton solution was kept 
over chloroform, so that it was always saturated with that antiseptic 
when used. 
2. Sulphuric acid. — Kahlbaum’s pure acid has been used. As solvent 
for the tyrosin, a mixture of 1 volume of the acid with 10 volumes of 
distilled water was used. Morner’s reagent consists of 55 volumes of 
concentrated acid, 45 volumes of distilled water, and 1 volume of formol. 
The concentration used for dissolving the tyrosin was fixed upon as being 
of suitable strength for solvent purposes, and, at the same time, as 
admitting of being brought up to the concentration required by Morner 
by the subsequent addition of an easily measurable volume of concen- 
trated acid. 
Sulphuric acid of the same concentration as the reagent is also required. 
This is made up by mixing 55 volumes of concentrated acid with 45 
volumes of distilled water. 
