48 



Hydration and Growth. 

 Table 39. 



The relative swellings of the biocolloid without the culture salts 

 presents the general features of such mixtures, being highest in dis- 

 tilled water, next in potassium nitrate, less in acidified potassium 

 nitrate, less in citric acid, and varjong in the relations of the hj^droxid 

 and the alkaline salts. 



The plates in which the culture salts were incorporated showed 

 relative swellings which did not differ widely from the expectancy, 

 except in the swelling in alkaU and alkaline salts. The addition of the 

 dextrose could not be seen to exert any definite action. The outstand- 

 ing fact is the general retarding effect of salinity on the hydration 

 capacity, a fact of possible enonnous importance in the organism. 



A mixture including 4 parts of agar, 5 parts of gum arable, and 1 



part of gelatine was made and sufficient potassium chloride was added 



to make it 0.01 M of this compound. Swellings at 18° to 20° C. were 



as given in table 40. 



Table 40. p.eL 



Distilled mUs 512 



Citric add. 0.01 N 465 



Sodium hj-droxid, 0.01 M 214 



Hydrochloric add 0.01 M 535 



Hydrochloric add. potassium chlMide, 0.01 M 419 



A general restriction of nearly all of the swelling reactions is illus- 

 trated by the measurements in table 40, while the relative increase in 

 acids is high. 



As a further combination of two forms of carbohydrate, albumen, 

 amino-acids, and of the salts which are foimd in plants, a mixture was 

 made which contained the following material: 



Tablb 41. " fM. 



AwKt 6 



Aeada 2 



GeUtuM 1 



Alhnmin (PAoMohtt) 1 



PoteMinm nitnte 0.0068 



FotoHie pkoopliate. dibMie 0185 



Macneaom suh^iate (THfi) 0418 



Caldum nitrate (4HxO) 0398 



Total eolkid matmal 10 



Total natrioit salts 0106 



