( 251 ) 



according (o which the velocity of diffusion in colloids is as great 

 as in the water in which the colloid is dissolved. 



If it should be objected that these experiments were made only 

 with crystalloids, the investigations of C. Eykman 4 ) have shown con- 

 clusively that colloids can diffuse into other colloids (gelatine into 

 agar-agar). 



But before trying to establish the influence of a constant electric 

 current on the transition of enzyme into the agar-agar, we wished 

 to know to what extent the ferment would diffuse into the agar-agar 

 without the introduction of the electric current. 



Evidently this transition took place. This fact seemed to suggest 

 a means of extracting in an easy manner enzymes and perhaps pro- 

 enzymes as well, from the mucous membrane in not too impure a 

 stale. Perfect extraction would, ii is true, be unattainable in this 

 way, but there was a likelihood that the method might be employed 

 to determine in a simple manner the relative amounts of enzyme 

 in the various parts of a mucous membrane. 



II. Experimental method. 



Paris of a glass tube having in our experiments an internal dia- 

 meter of 22 mm. and a height of 30 mm., were ground tlat at one 

 end by means of emery and placed with that side on a glass plate, 

 plate glass being the best for this purpose. 



By means of a pipette 3 cc. of liquid agar-agar were put into each 

 little cylinder. I shall not discuss the way to prepare this liquid : it 

 is to be found in ail handbooks on the technics of bacteriology. It 

 must be observed, however, that it is advisable to let the agar-agar 

 solution cool down to =t 45° before measuring it in the pipette; 

 otherwise there is a danger of its flowing partly away from under- 

 neath the glass cylinder. 



After some time the agar colums have become solid and are placed, 

 still surrounded by the glass tube, on the spread out parts of the 

 membrane which, if necessary, has been previously cleaned. For this 

 cleaning which also may serve to remove the mucus, we take 

 NaCl 0,9%- Investigations especially made for this purpose on the 

 gastric mucous membrane have shown, however, that for this organ 

 at least washing with water gives satisfactory results. 



On the mucous membrane, which if necessary has been cleaned, 

 the agar-agar colums remain for 8 hours or more, in order to enable 

 enzymes and pro-enzymes to diffuse into the agar-agar. 



*) G. Eykman, Centralbl. f. Bakteriol. 29, 1901, S 841. 



