Dec., 1908.] 
The Effect of Alkaloids. 
405 
from the action of sunlight. There were two plants in each jar, 
held in place bv means of perforated corks which had been 
previously paraffined. It may also be mentioned that the corks 
were subsequently paraffined to the jars so as to prevent any 
evaporation of water except that through the leaves. 
The plants were subjected to the influence of a few alkaloids 
in solutions of various degrees of concentration in order to deter¬ 
mine the effect which these substances would produce upon the 
rate of regeneration of new shoots. The following alkaloids 
were used: Sulphates of atropine and strychnine, pilocarpine 
hydrochloride and digitalin, each in a (a) 0.01%, (b) 0.001%, 
and (c) 0.0001% aqueous solution. Each jar contained 400 cc. 
of the solution; distilled water was used for the controls. The 
Avater in all jars was changed at inter\ r als, and carefully A\-eighed. 
The full series of plants was kept always in the same place in the 
university greenhouse so as to insure equal conditions of light, 
temperature and air currents. 
The stems Avere CAit off with sharp scissors very near the base 
the second day after the plants had been transferred to the 
mason jars. The rudiments of new stems appeared shortly 
afterwards in the axils of the cotyledons. 
It is known that a close relationship exists betAA'een the 
quantity of transpiration and the amount of growth for a given 
length of time (3), and that the index of transpiration is usually 
relied upon in comparing the rate of growth under \ T aried con¬ 
ditions. Since transpiration is a continuous physiological process 
in li\dng plants it was hoped that such data might aid in obtaining 
an insight into the physiological condition of plants regenerating 
under the influence of the various alkaloids. Unfortunately these 
data do not always prove to be quite a reliable basis for com¬ 
parison of the actual amounts of regeneration for definite 
periods; they Avere therefore checked up bA- other data, as for 
instance, the AA-eight of plants. The failure of the indices of 
transpiration to offer a solid ground for the comparative studA r 
of the rates of regeneration in this particular case of the scarlet 
runner bean is probably due in a large measure to the circum¬ 
stance that the total surface area of the leaves, the number and 
form of Avhich differed during regeneration almost Avith each 
plant, is not sufficiently uniform; and consequently the amount 
of Avater lost through transpiration does not alwavs correspond 
to the real rate of regeneration. The folloAving table contains 
data on transpiration: 
