1 84 TRANSPIRATION AND ASCENT OF SAP ch, 



that they contained ample amounts of proteids and of 

 protoplasm to test the point. The results were as follows : 



Table 26. 

 Effect of Liquid Air <>n Vegetable and Animal Fluids. 



No. of 

 Bxpt. 



549 



550 

 552 

 553 

 479 



480 

 481 



482 



C x 10 5 



Untreated sap of root of Beta . . 

 Same sap frozen in liquid air . . . 

 Untreated sap of leaf of Chamaerops 

 Same sap frozen in liquid air . . . 



White of egg untreated 



White of egg frozen in liquid air . . 



Bull's blood untreated 



Bull's blood frozen in liquid air . . 



In no case was a sensibly greater depression detected 

 after exposure to liquid air. The diminution in the depres- 

 sion observed in the experiments 553 and 482 appears to 

 be due to the expulsion of dissolved gases. The frothing 

 of the sap of Chamaerops on thawing after treatment 

 with liquid air was very marked. This was not looked 

 for in the case of the bull's blood. 



Hence it appears that there is no reason to believe that 

 the application of liquid air leads to a concentration in 

 solutions in contact with proteids and protoplasm. 



Again, the sap extracted from plant-organs after exposure 

 to liquid air does not cause plasmolysis of the cells in these 

 organs. This was demonstrated both for the sap of the 

 root of Beta and for the leaf sap of Chamaerops. In the 

 case of the latter the demonstration is particularly con- 

 vincing. Sap from the frozen leaf was found to have a 

 depression of T517, while the value of A for that of the 

 untreated organ was 0"599. Yet the former caused no 

 plasmolysis in the cells of a section of the leaf mounted in 

 it, even after twenty minutes. The difference in concen- 

 tration indicated by these two freezing-points would of 



