MR. A. J. EWART ON ASSIMILATORY INHIBITION. 413 
TaBLE W. 
l day in Ol p.c.H,PO,.| After 2 days in 0:1 p.c. H,PO,. 
Bryum Plants almost unaffected. | In most leaves no evol® of O from 
cespititium. apical half, and here more or less 
cells may be dead. In rest -ac- 
tive assim. In 1 day fairly active 
assim. in all cases. 
Catharinea | As in Bryum. Few leaves active, evol” of O most 
undulata. weak, and all cells living ; in many 
assim. absent, and here more or | 
less cells dead. After 1 day weak 
evol» of O in latter case, active in 
former. 
Dicranum | Nearly all leaves living. | Most leaves and leaf-cells living. 
scoparium. No assim. In 1 day | No assim. After 1 day assim. 
weak or absent, but in| still weak or imperceptible. In 
2 days active. 2-3 days several leaves die but in 
rest assim. is active. 
It will be noticed that the mosses are very much more re- 
sistant than water-plants are; and though this is undoubtedly 
partly due to an inherent difference of vitality it is also certainly 
partly due to the fact that the acid solution penetrates with 
greater difficulty through the cell-walls of mosses than through 
those of water-plants. Pfeffer * has shown that the acid pene- 
trates both cell-wall and protoplasm and appears in the cell-sap. 
The death of a cell immersed in an acid solution is soon followed 
by the contraction of the cell-contents and a rapid disorgan- 
ization and decolorization of the chlorophyll grains. 
Effect of Alkali upon Assimilation. 
Darwinf, in 1882, noticed that treatment with dilute alkalies 
caused in many cases in the living cell a precipitate to be formed 
in the cell-sap, and that only after prolonged exposure in 
very dilute solution the cells are killed. "The precipitate con- 
sists, as has been conclusively shown by Pfeffer ț and Klein $, 
* Pfeffer, “Ueber Aufnahme von Anilinfarben in lebenden Zellen," in 
Untersuch. aus dem Bot. Inst. zu Tübingen, p. 290. 
t Darwin, Insectivorous Plants, 1882. 
1 Pfeffer, loc. cit. (Ueber Aufnahme von Anilinfarben), p. 240. 
§ Klein, in Flora, 1892, p. 400; in Ber. d. Bot. Gesell. 1892, p. 237; 
in Bot, Centralblatt, 1894, Bd. lvii. p. 187. 
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