226 
Notes . 
still larger amount, but experiments, though many times repeated, 
gave an almost uniformly negative result. 
Thus seedlings vigorously growing in a pot were kept for several 
days in the sun, in a dry atmosphere (to increase transpiration) 
containing a much larger quantity of carbonic acid gas than nor- 
mally, but only a very little starch was found in the green leaves, and 
that was close to the vascular bundles. A similar result was obtained 
in a moist atmosphere containing eight per cent, of C0 2 in the sun. 
Leaves, both young and older, whole and cut up into small pieces, 
were fixed in damp sawdust, and placed in the sun, in an atmosphere 
containing about eight per cent, of C0 2 , the amount found by 
Godlewski 1 to be most favourable to the formation of starch in leaves. 
These experiments lasted from several hours to several days, but the only 
result was, that sometimes rather more starch than usual was found in 
the cells adjoining the bundle on both sides ; in one experiment with 
the first leaf of the seedling this layer was crowded with starch-grains. 
In the last case it might be said that the starch was simply formed 
from the reserve-material in the seed (which contains a good deal of 
oil but no starch) and was not therefore a product of assimilation, but 
this will not apply to the other cases mentioned, as in the majority of 
these the seed had been used up weeks before. 
I also tried feeding with glucose and cane-sugar, both with whole 
plants and picked leaves, — whole and cut up in pieces — the strength 
of sugar-solution varying from twenty per cent, of glucose up to the 
syrupy glucose itself, but the result w r as always negative. The same 
was the case when the two modes of experiment were combined, i.e. 
feeding with sugar in an atmosphere containing eight per cent, of C0 2 
in the sun. I never found any more starch than has been described 
above. 
From the papers of Bohm, Schimper 2 , A. Meyer, and others, it would 
appear that the green leaf of the onion does not form starch at all. 
Schimper gives a series of Euphorbia- species, showing all grades 
between a copious formation of starch and a very scanty one (as e.g. 
in E. lathyris , where it is present almost exclusively near the vascular 
bundle and at the base of the leaves), and then cites as the extreme 
case the onion which makes no starch at all. From the above, 
however, it is evident that the onion is rather to be considered as an 
1 Flora, 1873, p. 378. 
2 Bot. Zeit. 1885, pp. 453, 456, 504. 
