igoo-i.J Effects of Watkr on Foliage Leaves. 313 



From these experiments, and from others not recorded, the 

 conclusions may be drawn that, while a solution applied in the 

 form of a fairly large drop ma)' be harmful, applied as a fine spray 

 it may not be so ; that it is the upper surface especially that shows the 

 " scorching," no matter whether the solution be applied to the lower or 

 to the upper surface of the leaf ; and that calcium carbonate may be 

 absorbed in the presence of moisture and carbonic acid gas. 



Series III. 



On the action of strong solutions upon Spirogyra. 



CUSO4, m/S, one and three-fourths hours, no plasmolysis, 

 chlorophyll band broken up and of a lighter green colour, 

 spiral form lost, protoplasm very granular, and excepting 

 these granules it seemed to be dissolving, membrane not 

 visible.* 



HgClo, m/8, one and a-half hours, no plasmolysis, chloroplast 

 yellow and has lost its form, protoplasm full of dark 

 granular bodies each having a bright red center. 



PbA.j, m/8, two hours, no plasmolysis, protoplasm full of very 

 fine granules which are not dark, chloroplast shrunken but 

 still spiral. 



FeS04, m 8, one and a-half hours, no plasmolysis, chloroplast 

 yellowish, broken up into fragments each retaining a 

 pyrenoid, the walls between any two cells constricted and 

 of a beautiful deep blue colour, the other walls of the cells 

 of a faint blue tinge giving the whole a blue cast. 



HCl, m/8, one and three-fourths hours, no plasmolysis, chloro- 

 plast yellow, protoplasm dissolving, no granules, band has 

 kept its form and is very conspicuous. 



NaOH, m/8, two hours, no plasmolysis, chloroplast of a light 

 yellow colour and dissolving, protoplasm dissolving. 



NH4OH, 5^, one and three-fourths hours, no plasmolysis, 

 chloroplast in pieces and dissolving, general colour light 

 yellow and the cells swollen. 



^ Nageli (1893, p. 1-5') states that copper in very strong solution causes extreme plasmolysis ; and 

 that weaker solutions cause a chemical poisonous action with a breaking up of the chlorophjU bands. The 

 strong solutions used by Nageli are therefore much stronger than m/8. 



