1887. | BOTANICAL GAZETTE. 79 
elongated palisade cells, and usually about three layers of 
spongy parenchyma, more closely packed than usual. The 
chlorophyll bodies are small and thickly and evenly distrib- 
uted throughout the mesophyll cells. 
The first indication of the approach of autumnal changes 
is the withdrawal of the contents of the mesophyll cells. This 
goes on gradually, but the cells are seldom emptied. he 
amount of protoplasmic cell contents lost to a plant by the 
fall of its leaves must be very considerable. The whole mass 
of the chlorophyll bodies in any cell is much reduced by this 
process of withdrawal (see figures 2 and 3). t the same 
time the protoplasm of the cell seems to dispose of much of 
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* 
Fra. 1. Fig. 2. 
its substance in the manufacture of cellulose, chiefly in the 
palisade cells, in which it is deposited upon the cell walls in 
successive layers, either uniformly or in restricted patches, or 
Is used occasionally in building a transverse partition across a 
palisade cell (fis. 4). Inevery case the lines of stratification 
are beautifully marked. That this deposit is cellulose was 
determined by the ordinary tests for that substance. During 
these changes the chlorophyll bodies are seen both to disin- 
tegrate and to blend together in larger masses. In the case 
of the red leaf these larger masses often become invested by 
a pellicle which appears to be cellulose. 
In the leaf which has become brown (fig. 2), a greater 
amount of cell contents remain than in the red, the chlorophyll 
bodies do not mass together so much, and the cell sap is a 
dirty brown, 
-in the red leaf (fig. 3) the cell contents are even more 
reduced, some cells being almost empty, the remaining con- 
tents are mostly collected in masses of considerable size and 
