SEA-FISHERIES LABORATORY. 395 
portion and filtering off the precipitated proteid; the 
filtrate becomes red on boiling, if tyrosin is present. 
Tryptophane gives a reddish violet colour with 
bromine or chlorine water. 
The results were as follows:—The fibrin was all 
digested in the acid solutions (1) and (4); about three- 
fifths on the average was left in the alkaline mixture (2), 
and a little less in the neutral (3). The biuret reaction 
was very good in (1), medium in (2) and (3). Tyrosin 
reaction was good in (1), medium in (2), and fair in (8). 
There was practically no tryptophane in any of them. 
It will be noticed, therefore, that digestion proceeds best 
in acid media, the reverse of the process in the Crustacea. 
With the peptone solutions (5), (6) and (7), though the 
same tests were made, it was a diminution of the biuret 
tint that was looked for, since digestion would convert 
the peptone into more simple products. The results were 
almost negative; the residues all gave a strong biuret 
reaction and no tryptophane; the tyrosin reaction was 
good, but it was found later that the peptone itself gave 
this reaction. If there are therefore any ereptic ferments 
present, they are in small quantities only. 
Kixperiments (8) and (9) were for the purpose of 
testing for fat digestion; the methyl acetate was. broken 
up into acetic acid, which was estimated by titration with 
decinormal sodium hydrate in presence of phenol 
phthaléin. 
No. (9) was a control, and required 1°3 c.c. . NaHO 
to neutralise it, whereas No. (8) required 10°6 c.c. - NaHO 
to neutralise it and smelt strongly of acetic acid. 
No. (10), after standing 48 hours, gave no blue 
colour with Iodine, the starch had all been hydrolysed. 
