52 



CARNEGIE INSTITUTION OF WASHINGTON. 



When chlorides of sodium and potassium were tested, it was found 

 that pentosan-albumin mixtures simulating protoplasm showed in- 

 creased hydration in the potassium chloride only as indicated in the 

 tables. 



Up to this point colloids including only two of the supposed main 

 elements in protoplasm have been used. An agar-gelatine mixture 

 was now made, to which was added a thousandth part of a soap which 

 is probably nearly all sodium stearate. The results of the hydration 

 swellings are given below : 



Hydration of plates of agar 3, gelatine 2, Ivory soap 0.005 g. at 15° C. Swellings given in 



thickness and volume. 



This biocolloid, representing more nearly the colloidal constitution 

 of living matter, was seen to have higher hydration capacity in all 

 salt solutions and to have such capacity lessened in even the very 

 dilute acid. A similar preparation, in which the soap was pure 

 potassium oleate, gave results less marked as to the action of the salts,, 

 but the increase in the balanced solution was proportionately much 

 greater and the retarding effect in acids much greater. Ample justi- 

 fication exists, therefore, for a correction of the earlier statement as to 

 the effect of salts of the common metals on biocolloids, which have 

 been found to offer many profitable analogies to living material. The 

 correction implies that we may confidently look to these salts as accel- 

 erators of hydration and growth or as increasing the water-deficit of 

 living matter. 



I have previously pointed out, in many papers, that the commoner 

 amino-acids (glycocoll, alanine, phenylalanine, asparagine, and histi- 

 dine) which have been proved to promote growth also accelerate 

 hydration in biocolloids. 



As an additional step in this work, the effect of the water-soluble 

 B-yeast vitamin on biocolloids and living and dead cell-masses was 

 measured. Solutions of this material at 0.1 per cent, having an acidity 

 of Ph = 5.25 as determined by the colorimeter method, were used, 

 and measurements were taken by the auxograph. The vitamin was 



