MacDOUGAL— HYDRATION AND GROWTH. 353 



total of 2630 per cent, and which had stood in the solution without 

 any perceptible change for a few hours after the close of the test 

 was now treated to a o.oi M asparagin solution. The mechanical 

 disturbance which might result from changing the liquid in the dishes 

 was minimized by fractionization. About one third of the water 

 was removed then the level was raised by the addition of asparagin 

 solution and this was repeated about a half dozen times, the final 

 result being a solution which was diluted slightly below hundredth 

 molecular. A slow expansion began at once which continued for 

 about 20 hours, which raised the total hydration of these sections to 

 2890 per cent., an increase of 230 per cent., due to the action of the 

 asparagin on sections which had undoubtedly been reduced in mass 

 somewhat by solution from the surfaces. 



The presence of asparagin in the water in which swelling of 

 gelatine was carried out, produced an uncertain effect by reason of 

 supposed solution or dispersion of the gel. Neither can much be said 

 concerning its action on agar-gelatine mixtures, except that the re- 

 sults show a maximum at o.oi M. 



When the asparagin is applied to mixtures in which the gelatine 

 is replaced by an albumin, the results included some special reac- 

 tions. Plates of agar and oat-protein were made up to contain 8 

 parts of the first and 2 of the last, coming down to a thickness of 

 0.22-0.23 nmi. These swelled at 17° C. to the proportions shown in 

 the table, which in some cases exceeded that in water. The swell- 

 ing in concentrations as high as o.oi M were but little below that in 

 water. 



Glycocoll has been used in many cultural tests with plants and 

 various interpretations have been placed on its accelerative influence 

 on growth, and its influence on swelling therefore has an unusual 

 interest. 



Thin sections of agar swelled in all glycocoll solutions less con- 

 centrated than 0.3 M to the amplitude attained in water and exceeded 

 it in some cases, a fact which for the first time gives a sound basis 

 for results in which growth was accelerated and the total increased 

 by this compound. 



Another pentosan, gum tragacanth, was dried from solutions to 



PROC. AMER. PHIL. SOC, VOL. LVUI, W, OCT. 21, I919. 



