74 Proceedings of Royal Society of Edinburgh. [skss. 
drops, and examined microscopically for crystals of 
leucin or tyrosin. 
On several occasions, when leucin or tyrosin were 
suspected, a portion of the filtered fluid was tested 
with Millon’s reagent. The precipitate which formed 
was filtered off, and the filtrate evaporated down to 
small bulk. Any change in the colour of the solution 
was observed, and a few drops of the concentrated 
liquid were examined microscopically. 
5. 10 c.c. of X were added to 20 c.c. of a solution of cane 
sugar. The two fluids were shaken in a test tube. 
The test tube was plugged, and placed, as before, in 
the incubator. 
The mixture was tested with Fehling, and any 
reduction noted. As in the case of 1, the phenyl- 
hydrazine test was frequently applied. 
6. 10 c.c. of X were added to 50 c.c. of fresh milk diluted to 
100 c.c. with water. The mixture was stirred, covered, 
and placed in incubator. Any special curdling of the 
milk was noted. 
7. 10 c.c. of X were placed in a test tube, and put in incubator. 
The extract was then tested with Fehling’s solution, 
and any reduction was noted. 
In order to compare the results of the action on fibrin by the 
extract in alkaline and acid media, with the results in alkaline 
and acid media alone, confirmatory tests were frequently applied 
(the strengths of the solutions of hydrochloric acid and carbonate 
of soda being the same). 
By means of these tests one was able to note : — 
1. The conversion of starch by X into a reducing agent, and 
this probably by an enzyme similar in its action to ptyalin 
or amylopsin. 
2. The change in fibrin when acted on by X in a watery 
solution, and the presence or absence of proteoses. 
3. The change in fibrin when acted on by X in a 0*2 per cent. 
hydrochloric acid solution, and the presence or absence 
of peptones, the result of the activity of an enzyme 
similar to pepsin. 
