Hydration Effects of Amino-compounds. 35 



4. Glycocoll was used in extending these experiments, and it 

 was found to exert an accelerating effect on agar when mixed 

 with soy bean albumin, gelatine and similar increases were also 

 shown when the agar was partly replaced by such mucilages as 

 that from Opuntia, acacia and cherry gum. 



5. Living and dried sections of tomato fruits, growing cell- 

 masses of stems of Phytolacca, and joints of Opuntia, the cell-sap 

 of which has varying acidity, showed the greatest swellings in 

 alanin, phenyl-alanin, glycocoll and ammonium hydroxide as 

 compared with results in water and organic acids, with but few 

 exceptions. Taking water as unity living sections of Opuntia 

 discata showed swellings of 1. in alanin, 1.5 in phenyl-alanin, and 

 an equal increase in glycocoll. Dried sections of the same material 

 showed swellings of 1.3 in alanin, 1 in phenyl-alanin, and 1.4 in 

 glycocoll solutions. Living sections of Opuntia leptocaulis swelled 

 1.4 in alanin, 1.2 in phenyl-alanin, 1.55 in ethylamine, while 

 dried sections of this species gave increases of 2 in alanin and 1.5 

 in ammonium hydroxide and 2.2 in phenyl-alanin as compared 

 with water. 



6. The swellings or increases due to hydration were determined 

 by the use of the auxograph. It has been found that the hydration 

 of dried sections of such pentosans as agar causes changes which 

 are the reverse of those which ensue during desiccation. Plates 

 of this substance poured from a warm 2.5 per cent, solution, which 

 were fastened at the margin in such manner as to prevent shrinkage 

 in area and to allow decrease in thickness only, when swelled 

 showed increases of not more than 4 and generally as little as 2 

 per cent, laterally, while swelling 4,000 per cent, in thickness. 



7. Sections of gelatine from plates cast in the above manner 

 may show a lateral expansion of 8 to 40 per cent, while swelling 

 500 to 2,000 per cent, in thickness, in water and in acid solutions 

 with a pH value of 2. 



8. The swelling of gelatine which showed a pH value of 5.2 in 

 an 8 per cent, solution in nitric and hydrochloric acid at a pH 

 value of 2, in succinic acid (0.01N) at a pH value of 3.05 and in 

 amino-succinic acid (aspartic acid) at a pH value of 3 was much 

 greater than water, but the swelling in alanin, phenyl-alanin and 

 glycocoll was less than that in water. 



