4 j 6 
Notes . 
oxygen was observed from any of the cells even though the chloro- 
phyllous contents retained an almost normal green colour. If kept 
for the same time in a semi-saturated solution of chloroform in water, 
many cells are still living and plasmolysable ; but either no evolution 
of oxygen or in a few cases a faint or doubtful one is shown on 
examination. Next day a distinct to moderately active power of 
C0 2 -assimilation is shown by living cells, but these are extremely few 
in number, most having died. Kny largely employed as test-bacteria 
those taken from putrescent fluids containing meat, and moreover did 
not consider that it was necessary to ring the preparations in order 
to exclude external oxygen. Under these conditions however there 
is a serious liability to error, for such fluids almost always contain 
facultative or partial anaerobes which continue to move in the absence 
of oxygen and are attracted by the nutritious substances exuded from 
dying cells. Such movement continues in the darkness though it may 
appear as if it recommenced immediately the preparation is exposed 
to light. 
The same author also states that cells killed by acid and by the 
action of strong induction-currents might continue to assimilate 
carbonic acid, and in the latter case with an increased activity ! 
A possible explanation of these results has already been given \ and 
it seems almost incredible that so keen an observer as Kny could have 
been led into so palpable an error. The actual experimental work 
seems however to have been performed by Kny’s 2 assistant, and it is 
hardly necessary to emphasize the fact that the delicate bacterium- 
method can only be trusted to yield accurate results when it is properly 
applied by a capable experimenter. 
Elodea is a much more suitable plant for experimentation than 
Spirogyra ; and if a plant of Elodea is kept for one day in a saturated 
watery solution of chloroform, all the cells are killed and no trace of 
an evolution of oxygen from them can be detected. A plant suddenly 
saturated with a watery solution of chloroform containing a slight 
excess of the latter in the form of a fine emulsion, becomes covered 
with gas-bubbles if exposed to sunlight, and from the cut end of the 
stem bubbles derived from C0 2 -assimilation continue to escape 
actively for five minutes, then slowing and ceasing in the succeeding 
1 Bot. Cent.-bl. 1897, Bd. lxxii, No. 9 (Relations of Chloroplastid and Cyto- 
plasma). 
2 Kny, 1 . c., p. 403. Bot. Cent.-bl., 1898, Bd. lxxiii, p. 439. 
