ABSORPTION OF CORNSTALK TISSUE 
127 
equal to that of acid and alkaline solution by the addition of any 
gum. If this were possible in this case the correlation would be 
very close. The proportion of swelling in corn tissue and Mac- 
Dougal’s Opuntia joints is remarkably similar in that the effects 
of water and sodium hydroxide are nearly equal and acid solu- 
tion causes two-thirds as much swelling. It is expected that differ- 
ent plants will vary in their hydration capacities. This would be 
especially likely if Dachnowski ^ is right in assuming that chem- 
ical and enzymatic actions are important factors. 
Conclusions . — The comparative rate of absorption of these 
constructed colloids is quite similar to that of corn tissue, which 
is, however, much lower. 
Plain agar has a very high rate of absorption. This could 
likely be reduced by the addition of a gum. 
Albumen added to agar greatly increases the absorption of 
acid, and reduces somewhat the absorption of water. 
Young corn stalk tissue has a water relation similar to that 
found for Opuntia joints. 
Department of Botany, 
Iowa State College. 
7 Dachnowski, Alfred. Effects of acid and alkaline solutions upon plants. Am. 
Jour. Bot., vol. 1, pp. 412-440. 1914. 
