MR. A. J. EWART ON ASSIMILATORY INHIBITION. 455 
largest and most fully-developed leaves. It is the age of the 
young leaf which is of primary importance with regard to its 
assimilatory powers, and the size of the developing leaf is the 
readiest, though not always the most accurate, indication of its 
age. Thus many actively assimilating early developed adult 
leaves are of smaller size than developing leaves which have not 
yet commenced to assimilate may be. If, however, at any given 
date it is always the largest and most fully developed leaves which 
are examined, this error is largely obviated. 
From the table (p. 453-4) it appears that when the foliage is 
developing in spring, it is only when the leaves have reached a 
certain size and condition of development, which varies very much 
in different plants, that any power of assimilation can be detected. 
If branches are cut towards the end of winter and brought into a 
warm room with their lower ends in water, the buds in Syringa 
and Salix soon open and expand, though in other cases a long 
latent period intervenes. 
| After 4 weeks. 
| Fairly active 
| Assimilation. 
After 3 weeks. 
Weak Assimilation. 
After 2 weeks. 
No Assimilation. 
Syringa vulgaris ...| Buds opened. L.¿; | Chlorophyll grains La B. íi; P.4 | 
.1; P. 1. | quite green and to L. 2; B. yy. 
| fairly PY L.$; 
B. }; P 
| Salix daphnoides ...| Ohlorophyll grains | CET L.4; L. 4; B.#. 
B | 
small and yel- | 
lowisb. L. 2; B.}.. | 
Comparison with the results in the previous table shows that 
under these conditions the power of assimilation takes longer to 
develop, but becomes active whilst the leaves are still relatively 
small. This is due to the abnormal conditions, and to the fact 
that the leaves on a cut branch rarely attain their full normal 
size. 
In the young developing leaves of adult plants, perennials, 
aunuals, mosses, &c., the results obtained are very similar to 
those already given. 
