DEPARTMENT OF BOTANICAL RESEARCH. 



61 



sideration of the known laws of imbibition of its components separately, 

 but it is confidently predicted that with wider evidence the general 

 behavior of a biocolloid may be foretold. 



Preliminary tests of imbibition by biocoUoids were made chiefly 

 with a single concentration of the reagent, which is taken to lie within 

 the possibiUties of conditions in the cell. Extension of the investiga- 

 tion will necessarily include the deUneation of effects of reagents down 

 to the vanishing-point and up to various maxima, which may run as 

 high as 0.05 M. in some cases. The general effect of concentration 

 may be illustrated by the swellings of a biocolloid of 90 parts agar and 

 10 parts glycocoll, which were as follows: 



From this it may be seen that an inhibiting effect on imbibition in the 

 colloid was exerted by these salts, the effect increasing with the con- 

 centration and the least swelling taking place in the calcium compounds. 



It is probable that some organs and more than probable that some 

 cell-structures contain a larger proportion of albumen or its derivatives 

 than of amorphous carbohydrate, in which case the effect of concentra- 

 tion of salts on imbibition might be illustrated by the swellings of a 

 biocolloid consisting of 90 parts gelatine and 10 parts mucilage from 

 Opuntia, which were: 



The swelUng increases with concentration of potassium nitrate within 

 the range used and appears to decrease slightly within similar con- 

 centrations of potassium chloride, and is checked to a greater extent 

 by calcium chloride, although the last-named solution would have a 

 slightly alkaline reaction due to the hydi'olysis of the salt. 



Nucleinic acid is a constituent of the nucleus, and its swelling reac- 

 tions carry much interest. The results were as shown at top of the 

 following page when combined in proportion of 10 parts nucleinic acid 

 to 90 parts agar : 



