PLANT-AUTOGRAPHS—BOSE. 427 
excitations at the moment of ‘‘make”’ or ‘‘break’’ of the current. 
In most cases there is no excitation during the continuation of the 
current. At the ‘‘make” excitation takes place only at the cathode; 
at the ‘‘break”’ of the current, however, excitation is induced once 
more, but this time at the anode. These characteristic effects I find 
repeated also in the plant. At this point it is interesting to institute 
a comparison between the sensitiveness of a plant and a human 
being. The most sensitive organ by which an electric current can be 
‘6 
Py 
aed 
Fig. 4.—Apparatus for determination of latent period of Mimosa. M, spring motor. 
W, winding disk. C, projecting catch. H, release handle, pressure on which also completes 
primary circuit of induction coil. K’, short circuit key. The automatic break consists of 
contact rod adjusted by micrometer screw A. 
detected is our tongue. An average European, according to Laser- 
stein, can perceive by his tongue a current as feeble as 6.4 micro- 
amperes—a microampere being one-millionth part of the unit of 
current. ‘This value might be subject to certain variation, depending 
on racial characteristics. One might expect that the tongue of the 
Celt would be far more excitable than that of the stolid Anglo-Saxon. 
In any case the superiority of man has to be established on foundations 
more secure than sensibility; for the plant Biophytum, I find, is 
