Division in the Root of Vicia Faba. 161 
total growth takes place between 7.30 a. m. and 5.30 p. m.,” 
or, in short, growth by day exceeds that by night. 
It seems difficult to account for such results as those ob- ~ 
tained by Sachs. The experiments, performed by the wniter, 
were conducted under perfectly natural environmental con- 
ditions, and moreover, not one of the results would stand as 
an exception to the general conclusion. And as proof that no 
extraneous or mechanical factors could have interfered during 
the night, are the experiments watched continually during the 
entire period of twenty-four hours. The latter are in no way 
different from those in which observations were made during 
the day until 4 or 5 p. m., and where the night growth was 
obtained by the reading of the next morning. 
The rate of growth was obtained by measuring the amount 
of growth during a definite number of hours of the day or 
night, and calculating from this the rate per hour. Thus, for 
example, to take the root, recorded on Plate I, Fig. 1—here 
the growth from Io a. m. to 4 p. m,, or for six hours, was 
I3 mm.,—a rate of 24 mm. per hour, and from 4 p. m. to 
g a. m. of the following day,—or for a period of 17 hours,— 
the growth was II mm.,—a rate of 14 mm. per hour. 
From the above experiments and observations, but one 
conclusion can be drawn, and this, as before mentioned, is the 
fact that the rate of growth of roots is greater during day than 
during night. 
B. RELATIVE GROWTH OF Roots IN DIFFERENT CHEMICAL 
SOLUTIONS. 
These experiments were performed with a view to ascertain 
the action of chemical solutions of various strengths on the 
growth of germinating seedlings. 
Dr. Rodney True’ has recently published some instructive 
results on the toxic action of acids and salts on seedlings. 
1 Toxic Action of Dissolved Salts. R. True. Bot. Gazette, vol. 22, 1896. 
