6S 



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 (3). 



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 resiilts Avere 

 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 onl3^ 



Experiments (8) and (9) were for the purpose of 



testing for fat digestion ; the methjd acetate was broken 



up into acetic acid, which was estimated by titration with 



decinormal sodium hydrate in presence of phenol 



phthalein. 



N 

 No. (9) was a control, and required 1*3 c.c. — NaHO 



N' 

 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 xo blue 

 colour with Iodine, the starch had all been hydrolysed. 



