COLLOIDAL BEHAVIOR OF PLANT PROTOPLASM. 153 



Conclusions Founded on Newly Obtained Results. 



The further development of our knowledge on this subject has 

 been attempted by experiments arranged to obtain evidence upon 

 four topics, viz: (i) the proportions of carbohydrate and albu- 

 minous matter in a colloid of the highest hydration capacity; (2) 

 the substances or ions of biological significance which would raise 

 the hydration capacity of these phytocolloids to the highest limit ; 

 (3) measurement of the relative efifects of some metallic bases upon 

 a carbohydrate colloid ; and (4) determination of the amplitude and 

 continuance of alternating or repeated effects of renewed or replaced 

 solutions. 



1. By the use of the pentosan, agar, as representing the acid car- 

 bohydrate and of gelatine for the amphoteric albuminous component 

 trials were made to ascertain what proportions of these substances 

 would show hydration capacities of a range comparable to that of 

 living matter. A mixture containing one part carbohydrate and 

 three parts albuminous matter shows the highest general hydration 

 capacity under the influence of hydrogen, hydroxyl ions and the 

 ions which may be derived from amino-acids. Biocolloids high in 

 albuminous matter swell most under the action of the hydrogen ion. 

 Biocolloids containing 40 per cent, or more carbohydrates swell most 

 in amino-compounds. Balanced biocolloids swell most in the pres- 

 ence of hydroxyl ions. These reactions are parallel to those of 

 living and dried cell-masses of plants, and follow through the sea- 

 sonal variations determined by chemical analyses. 



2. Biocolloids of which more than a fourth is carbohydrate are 

 highly sensitive to the action of hydrogen ions, which restrict 

 hydration. 



3. The basic histidine and glycocoll which is slightly on the acid 

 side of neutral increase hydration in biocolloids containing more 

 than 40 per cent, carbohydrate. Maximum swellings of 4300 per 

 cent, by a mixture of i part agar and 3 parts gelatine in acid repre- 

 senting a high concentration for plant juices, and of 3930 per cent, 

 by a mixture of 2 parts agar and 3 of gelatine in histidine are of 

 great physiological interest. But little information concerning the 

 presence or action of the basic amino-compounds in plants is avail- 

 able. 



