272 
The amount of pepsin in the lower part of the tube was very 
considerable (25 mgr), while 0,1 mgr. of this enzyme in 10 ce. 
0,2°/, HCl dissolves in Merr’s tubes from 5 to 6 mm. of coagulated 
white of a hen’s egg in 24 hours at 37° C. What was lost of it 
in mixing the pepsin with the heated agar (which was directly after 
cooled down in ice) and what was lost in the washing of the tubes 
with sodium-hydrate, through which of course also a little of the 
pepsin at the surface of the pepsin-agar colamn was attacked, could 
only be very insignificant in relation to that considerable amount 
of pepsin. It was assumable, therefore, that the concentration of the 
enzyme in the reservoir sufficed to prevent in the several tubes 
considerable differences in the degree of the rise of the enzyme in 
the agar-column above the pepsin-agar. 
After a few days every time two tubes were opened, one with 
and one without protein. To this end a circular incision was made 
into the glass just on a level with the boundary between the pepsin- 
agar and the column above it and the glass was broken by touching 
it with a heated rod. The lower part of the tube could then readily 
be removed and the whole content be slid out and put on filter- 
paper. 
It might be that the fluid in the capillary spaces between the 
agar and the glass should have taken up more or less pepsin from 
the pepsin-agar: a possibility which deserves the more consideration 
as occasionally it could be observed at the free surface of the column 
that some fluid had been pressed out, which could dissolve fibrin, 
though it be in a very small degree. That is why after the reser- 
voir of pepsin had been cut off from the agar-column, this column 
was immersed for some moments in 1°/, Na,CO,, then washed im- 
mediately in 0,1°/, HCl and dried by cautiously rolling it along 
filterpaper. 
We now had to determine the level to which the pepsin had 
penetrated into the agar-column. With a view to this we proceeded 
as follows: after cutting off a layer of 2 mm. thickness, there where 
the column had been in direct contact with the pepsin-agar, 
the column was divided into three cylinders of equal length, mostly 
13 mm. in length, sometimes 15, if the diameter of the tube had 
been somewhat smaller, and if the whole column had consequently 
been somewhat longer. In this division we started from the bottom, 
so that the layer nearest to surface could be rejected. The cylinders 
were weighed, rubbed down in a mortar with See. 0,1°/, HCl. For 
every one of these fluids we now determined the time in which 
1 ec. coagulated 5 ee. of milk at 27° C. We ascertained the com- 
