1 84 BIO-CHEMICAL JOURNAL 



Another 2 c.c. were added, and after 24 hours the conductivity was found 

 increased by 208 gemmhos. That is, as I interpret it, a part of the 

 first dose of KCI was taken up by the gelatin. It is impossible to 

 compare directly these figures with those obtained on a similar experi- 

 ment with distilled water without gelatin, since the proportion of water 

 taken up in the swelling of the gelatin is unknown. 



Again, if gelatin has the power of taking up electrolytes, it is to be 

 expected that commercial gelatin and ' washed ' gelatin would show a 

 difference in their power of taking up more, since commercial gelatin 

 has already a larger percentage. The following experiment was made 

 to find out if this is so : 



Experiment: 12 grams (air-dry) of commercial and 'washed' 

 gelatin were soaked for 20 hours in distilled water. The conductivity 

 of the water was then found to be : 



Commercial gelatin : 553 gemmhos. 

 Washed ,, : 7-7 gemmhos. 



Two solutions (very dilute) of calcium sulphate and phosphate 

 were made equal in conductivity to each of these extracts by adding, 

 drop by drop, a saturated solution of these two substances in distilled 

 water. Of these solutions a volume was taken equal to that of the 

 water in two flasks in contact with the two kinds of gelatin, this was 

 found to be (by weighing) 176 grams. Then to each of the four 

 flasks 1 5 c.c. of the above-mentioned saturated solution of calcium 

 sulphate and phosphate were added, and the increase of conductivity 

 so produced was determined. If a part of the added electrolytes were 

 taken up by the gelatin there should be a greater rise of conductivity 

 in the cases of the watery solutions than in those where gelatin was 

 present. The results actually obtained arc rather difficult to interpret. 

 To take first the 'washed ' gelatin and the watery solution equal to it 

 in conductivity. The rise of conductivity in the latter by the addition 

 of 15 c.c. of the calcium sulphate solution was 163 gemmhos at 10. 

 Where the gelatin was present the first effect was a rise of 238 

 gemmhos, owing, no doubt, to the electrolytes not at once diffusing 

 into the water contained in the swollen gelatin, this steadily diminished, 

 and in about forty-five minutes had become 128 gemmhos. But then 



