526 Townsend. — The Correlation of Growth 
accelerated within six hours. The acceleration continued 
from one to five days, after which came a period of normal 
growth, followed in some cases by a period of retardation 
(Table XIII). 
Roots . — No appreciable change in the rate of growth of 
roots could be detected in the older plants, even when the 
entire stem, of Phaseotus for example, was cut away, leaving 
only the first pair of leaves. Also in Catla no change was 
produced in the rate of growth of the roots by the removal 
of a leaf, although this same injury produced such a com- 
paratively sudden and marked change in the rate of growth 
of the young leaves. 
Cuttings . — A few experiments were performed with cuttings 
of Salix , the results of which were similar to those already 
shown. Owing however to the small number of experiments 
alnd to the slight changes in the rate of growth, further 
investigations are necessary before the results can be tabulated 
with satisfaction. 
Phycomyces . — When the mycelia were cut near the base 
of the sporangium-stalk, the raite of growth of the stalk was 
immediately reduced in a very marked degree, but in no case 
examined did the growth entirely cease. The sporangium- 
stalk began in a few minutes to recover its rate of growth, 
and in from thirty to sixty minutes was growing again at the 
usual rate. No change was observed in the rate of growth 
of the sporangium-stalk if the mycelia cut were comparatively 
thin, or if the larger mycelia were cut only near the tips. In 
those experiments in which one of two or more sporangium- 
stalks was cut off, the uninjured stalk showed a still stronger 
retardation in the rate of growth than when the mycelia were 
cut, and the retardation in some cases continued for a longer 
time. But, as in the preceding experiments, the growth did 
not absolutely cease. 
While the above table would indicate that observations 
were made only at intervals of ten minutes, it was really 
the case that the plants were not removed from before the 
microscope. The treating and refocussing required but a few 
