© 
DR. A. J. EWART ON ASSIMILATORY INHIBITION. 507 
Many cells have by the plasmolysis been separated into two 
halves, a nucleated and a non-nucleated, and the chlorophyll 
bodies of both of these may in many cases be seen to be equally 
green. The green coloration of the chloroplastids of the non- 
nucleated half is especially well brought out, when, as is often 
the case in sugar solution, the cells form a purple-red sap which 
may be quite deep in colour. Apparently the chlorophyll grains 
may turn green without a nucleus being in organic connexion 
with them, for between the two protoplasts no filamentous or 
other protoplasmie connexions can be seen in many cases in 
Which the grains have become distinctly green. It is possible, 
however, that such counexions through which the nuclear influ- 
ence can be transmitted might have at first existed and later 
become broken off, for no further deepening of colour takes 
place, but instead the chlorophyll grains begin to alter and show 
degenerative changes. These take place much more rapidly in 
the non-nucleated portions, the chlorophyll grains here becoming 
finally quite small and colourless, and also, but much more 
slowly, in the nucleated portions, here becoming also smaller but 
acquiring a brownish coloration. If non-nucleated portions are 
separated by cutting open the cell to which they belong and kept 
in a hanging drop of sugar solution exposed to light, though 
they may remain living for a day, in all cases they die and 
decolorize without having acquired any perceptible greenish tinge. 
In a plasmolytic solution of KNO, the leaves do not turn at all 
green, but remain quite pale or yellow until they die. 
Experiments tried by placing sections of etiolated leaves of 
Phaseolus, Hordeum, and Avena and Cucurbita in plasmolytic 
sugar solution exposed to light failed, the sections under these 
conditions refusing to turn in the least green, though in many 
cases they were kept alive under examination for 3 days and 
more. Apparently the withdrawal of water by plasmolysis 
delays in all cases, and commonly inhibits, the turning green of 
etiolated chloroplastids. 
Assimilatory Inhibition in CO,-free atmosphere. 
Vochting * has shown that if exposed to light in an atmosphere 
free of all CO, leaves of Mimosa soon die and potato-leaves turn 
bluish green, show abnormal twistings and curvatures, and finally 
* Vochting, “Ueber die Abhangigkeit des Laubblattes von seiner Assimilations- 
Thatigkeit,” Bot. Zeitg. 1891, pp. 113 & 129. 
