15 



Referring to stomata, Mr. Bergen writes: "To some 

 extent they regulate the rapidity of trans[)iration, opening 

 77iO)'e irulel// in damp weather, and closing in dry weather," 



Vine^' Phyxiologij of PJanU however states, that Molden- 

 hauer supported by Amici, von Mohl, and Unger, find that 

 the stomata are chimed on rainy days and dewy nights, and 

 are open when the sun is shining upon the leaves I 



Such statements as the foregoing indicate that an hyper- 

 critical reviewer may himself be open to criticism. 



TRANSFERABILITY OF COLOR. 



Most of the coloring matters in cells can be dissolved out 

 by })ure alcohol. The veins of petals and leaves are speed- 

 ily tinged with colored solutions absorbed through the 

 stems ; the cellular tissue may also be tinged somewhat, but 

 much more tardily. A white petaled Cyclamen with a 

 crimson projecting central part or eye, placed in alcohol 

 changed to white at the center, and after the alcohol had 

 evaporated, it changed back to crimson, but a portion of the 

 red pigment, evidently dissolved out of the cells, penetrated 

 and tinged the veins of the reflected wdiite i)etals nearly to 

 the tips. 



The dark pur[)le eye of an Ixia, after remaining in a 

 tumbler of water for a couple of days entirely disappeared, 

 but the coloring matter reappeared in the veins and cellular 

 tissue of the white outer })ortion of the })etals. The yellow 

 [)igment in flowers, not l^eing dissolved in the cell sap, but 

 associated with granular substances in the cells, is not easily 

 transferred through the cell walls. 



In order to test the transferability of coloring matter by 

 some mechanical device roughly approaching the irritations 

 of insects, experiments w'ere made by brushing the colored 

 surface of the petal with a small camel's-hair brush such as 

 is used in water colors. 



Several blue violets taken from conservatories in winter 

 were selected, which, owing to cloudy weather [)erhaps, 



