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absorbed from them and enter the agar. As such were examined 

 pepsin, including pepsinogen, chymosin and prochymosin, enterokinase 

 and erepsin. 



2. The above-mentioned ferments can be extracted, partly at least, 

 by water from the agar-agar. Quantitative investigations have shown 

 even that pepsin -)- pepsinogen and enterokinase as well, distribute 

 themselves equally over the agar and water. 



3. The facts mentioned sub 1 and 2 suggest a simple means of 

 extracting the above-named ferments from the mucous membrane, 

 and of determining quantitatively the distribution of them. 



We have only to leave solid agar-agar columns of equal dimensions 

 on various parts of the mucous membrane for some time and make 

 subsequently a comparative quantitative determination of the specific 

 action of the watery agar extract. 



4. The results obtained with this new method with respect to 

 the distribution of the above-named ferments in the digestive tube of 

 the pig confirm those obtained by most investigators with the usual 

 extraction methods on the dog. 



5. The advantages of the method over the usual one consist, 

 besides in its greater simplicity, also in the fact that the enzyme 

 under investigation is much less polluted by decomposition products 

 of the mucous membrane. 



Especially for the investigation of the distribution of enzymes in 

 individuals who, when alive suffered from diseases of the stomach 

 or intestinal canal (ulcers in the stomach, the intestines, etc.) the 

 method seems to me likely to be of use. 



Moreover it is to be expected that besides the ferments examined 

 till now, others will also pass into the agar-agar, which will enable 

 us to make quantitative determinations of them in a similar way. 



Finally the method seems to me to deserve recommendation as it 

 can be applied in experiments at a lecture; at the same time, by 

 adding congo-red or a similar indicator to the agar, the amount of 

 acid or alkali can be demonstrated ocularly. 



Groningen, September 1907. 



