278 
After 3 days: 
weit Clotting |Cotorim Weight | Clotting |Colorim. Weight Clotting} Colorim. 
with am.-acids} 1 2.27 |l min| 5.5 112.28 122 min: 0.5 III 2.80| none 0 
without » 12.30 121 > San II 2.20 | none 0 III 2.16} none 0 
After 4 days: 
with am.-acids| I 2.35 |11/2 » 3.5 II 2.30 | 2 hour | 0.3 III 2.30; none 0 
without » 2.36 11 > 4.5 II 1.85] 8 min. | 1.7 {III 1.70 |25 min. 0.8 
here, owing to the dark colour caused by the action of strong min- 
eral acids on the carbonhydrate. It is possible, however, to remove 
the greater part of the nitrogenous substances by warming the agar- 
sol during 24 hours at about 50° C. The nitrogenous substances 
will then separate in flakes, so that they can be filtered off. In this 
way I obtained from an agarsol a sol which was scarcely opalescent 
and remained almost clear also after the clotting. The agarsol had 
been prepared in the usual way by warming it just sutficiently and 
then filtering it through cottonwool. It contained 1.6 °/, N of the 
solid substance. In the sol there was only 0.39°/, N after heating 
during 24 hours and filtering through compressed paper pulp at 
about 50° C. This gel was now compared in the usual way with 
the one that had been filtered only once, to the effect that there 
was no difference to be observed in the advance of the pepsin. In 
the gel containing only very little N we could make out in the 
lowermost cylinder, which had been situated at a few millimeters 
distance from the pepsin-agar, as much enzyme as in the gel 
which contained four times that quantity of nitrogen. 
That pepsin had no doubt advanced through diffusion. But this 
movement is very slow. 
Whereas after a few days a rather considerable amount of pepsin 
has penetraded from the reservoir at the lower portion of the tube 
into the adjoining agar, there is none or hardly any to be made 
out at a few centimeters distance, anyhow, if the gel has preserved 
its compactness. If, however, the gel contains protein, the enzyme 
has proceeded much further in the same space of time. 
In my opinion the foregoing warrants the conclusion that the 
movement of pepsin througb a gel which contains protein it is able 
