416 MR. A. J. EWART ON ASSIMILATORY INHIBITION. 
Effect of Antipyrin upon Assimilation. 
Hauptfleisch * noticed that in Elodea immersion in a l-per- 
cent. to l:-per-cent. solution of antipyrin causes pre-existant 
rotation to stop, hence it was to be expected that antipyrin: 
might also have some effect upon assimilation. In a 3 per cent. 
solution of antipyrin B. Termo at once ceases to move, in a 2-per- 
cent. solution a few Bacteria show slow translatory movement, 
but in a few minutes all come to rest, whether oxygen is present 
or not ; in 1-per-cent. fewer Bacteria move and not so rapidly as 
normally ; in 05-per-cent. the movement is only slightly slowed, 
in 0°25-per-cent. is hardly at all affected, and in O1-per-cent. is 
as active as in water. Hence observations cannot be made in a 
strength of solution stronger than 1 per cent.; the recovery is 
followed after washing and keeping in fresh water. 
The results of the experiments made with Chara fragilis and 
Elodea canadensis are given in Table Y. 
As regards rotation, it must be remembered that in Chara the 
rotation is primary, arising from an internal stimulus which is 
in continual action, whereas in Elodea the rotation is secondary 
and is only called into action by external stimuli. Leaves of 
Elodea, with the cells in active rotation, if immersed in a 1-per- 
cent. solution of antipyrin, show in them very slow rotation, and: 
in 2-3 hours none ; in 2-per-cent. solution in half an hour a few 
cells still show slow creeping rotation, and in 1 hour rotation: 
has entirely stopped, but on washing in water it very soon re- 
commences and is active again in a few minutes. 
After even 4 hours' immersion in 1-per-cent. or 2-per-cent.. 
antipyrin solution, the chlorophyll grains in Chara acquire a 
distinct brownish-green coloration, and may often, by becoming 
arranged in lighter (larger interspaces) and darker (smaller 
interspaces) areas, form an almost regular pattern over the cell.. 
All these cells after 4 hours’ immersion remain living and recover,. 
the brownish tinge being still present after 1 day in water, when 
assimilation is quite active in all cases but disappears in 2-3: 
days. In Elodea all the cells remain living, but neither of these 
effects are produced. After 8 hours in either l-per-cent. or 
2-per-cent., a few cells in both Elodea and Chara are killed and 
do not recover. After 24 hours immersion, in Elodea only a 
* P. Hauptfleisch, ** Untersuchungen über die Strömung des Protoplasmas 
in beháuteten Zellen," in Pringsh. Jahrb. 1892, Bd. xxiv. p. 221. 
