MR. A. J. EWART ON ASSIMILATORY INHIBITION. 461 
food-material, or by a closure of the channels through which 
these carbohydrates are removed. 
Cells in which the green colour of the chlorophyll grains is 
quite masked by the presence of a brown or reddish-brown 
pigment may show a distinct power of assimilation. If the 
reduction of the chlorophyll be complete, assimilation ceases. 
In certain cases isolated chlorophyll bodies may continue to 
assimilate for a short time after removal from the cell to which 
they belong. 
A developing leaf in which the chlorophyll grains are being 
formed “ab initio” by protoplasmic differentiation lacks at first 
the power of assimilation. The commencement of assimilation is 
determined mainly by the development of the chlorophyll 
pigment, but is also largely influenced by other indeterminate 
factors, probably plasmatic in origin. 
Postscript.—The above work was carried out in the Botanical 
Laboratory of the University of Leipzig during the years 1894 
and 1895, under the direction of Professor Pfeffer, to whom my 
sincere and cordial thanks are due for his able and kindly 
assistance as wel] as for his searching but friendly criticism of 
the facts thereby brought to light. 
Leipzig, April 1896. 
LINN. JOURN.— BOTANY, VOL. XXXI, 
