156 BOTANICAL GAZETTE [AUGUST 
higher animals differently according to the concentration and duration of 
action, so that the effects can be arranged in a graded series, he proposed to 
himself the solution of the question whether a similar gradation in narcosis 
existed among plants and the protozoa, in which the differentiation and 
division of labor has not gone so far. If, for example, their sensitiveness to 
external stimuli could be suspended more easily than other vital phenomena, 
it would be possible by partial narcosis to make them insensitive (7. ¢., to 
produce anesthesia), without at the same time suppressing those functions 
(growth, movement, etc.) by means of which a visible reaction could be 
executed. Thus an important means of analyzing irritable reactions might 
be secu 
fees securing suitable material (a matter of great difficulty), tests were 
made (1) by putting organisms into vials containing water with known per- 
centages of the narcotic, with precautions against its evaporation; (2) by 
using mounted preparations, the cover being supported, in which were intro- 
duced Pfeffer’s capillary tubes (for chemotaxis) or air bubbles (for aerotaxis) ; 
or (3) by means of hanging drop cultures in a moist chamber. The criterion 
for the existence of sensibility was the accumulation of the individuals in 
definite regions. 
Naturally, though not the chief aim, many observations were made on the 
effect of narcotics on motility. The resistance of nearly related organisms 
is very different; ¢. g.,one form of Bacterium termo ceased to move in 20 per 
cent. ether-water,*3 while many individuals of another form, apparently the 
same species, resisted a saturated solution of ether for five hours. Similarly 
Gonium pectorale has its movements slowed by 2.5 per cent. ether-water and 
wholly stopped by 20 percent.; whereas Chlamydomonas sp. ? moved normally 
in 20 per cent. ether-water and was only stopped by 60 per cent. Individual 
differences are also noticeable. 
Rothert found various forms in which the osmotactic, chemotactic, aero- 
tactic, or phototactic sensitiveness could be suspended by the narcotics, while 
movement was not. Thus in one form of &. ¢ermo, chemotaxis and aerotaxis 
were only slightly reduced by moderate concentrations, while osmotaxis was 
completely checked. In Bacit/us Solmsii chemotactic sensibility was stopped 
by chloroform but not by ether. 
A curious reversal of phototactic reaction occurred with chloroform, both 
in Chlamydomonas, which cannot be anesthetized, and in Gonium, which is 
easily made insensible. These organisms, which were reacting negatively, 
a to the paper, for Rothert specifically says (p. 15): “The question as to 
the nce of narcotics upon the motility of microorganisms I did not consider ae 
rohan of my investigations.” Nor are the researches confined to “microorganisms,” 
as this term is commonly used, though all the forms studied were microscopic. 
3 /. €., a 20 per cent. solution of a saturated solution of ether in water at room 
temperature; similarly designated in other cases 
Yeas Paes. pe Oe eae ene u 
