Dec, 1908.] The Effect of Alkaloids. 405 



from the action of sunlight. There were two plants in each jar, 

 held in place by 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%, 

 anvl (c) 0.0001% aqueous solution. Each jar contained 400 cc. 

 of the solution; distilled water was used for the controls. The 

 water in all jars was changed at intervals, and carefully weighed. 

 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 were cut off with sharp scissors very near the base 

 the second dav 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 between 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 varied con- 

 ditions. Since transpiration is a continuous physiological process 

 in living 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 were therefore checked up by other data, as for 

 instance, the weight of plants. The failure of the indices of 

 transpiration to offer a solid ground for the comparative study 

 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 which dift'ered during regeneration almost with each 

 ])lant, is not sufficiently uniform; and consequently the amount 

 of water lost through transpiration does not always correspond 

 to the real rate of regeneration. The following tal)le contains 

 data on transpiration : 



