REACTIONS OF INFUSORIA TO CHEMICALS: 
A CRITICISM. 
H. S. JENNINGS. 
In the January number of the American Journal of Physiology, 
Garrey ! gives the results of extended experiments on the effects 
of chemicals in causing motor reactions in the flagellate Chilo- 
monas. From the chemical side the paper is a valuable one, as 
being the most thorough study yet made of the specific effects 
of chemicals in causing reactions in unicellular organisms, and 
in treating the subject from the standpoint of modern physical 
chemistry. On the other hand, that portion of the paper which 
treats of the part played in the reactions by the organisms 
seems to me much less successful, and it is my purpose to 
point out certain criticisms on this part of the work. 
Garrey found that the motor reactions of Chilomonas are set 
strongly in operation by certain chemicals, ** very swift shooting 
movements being induced," so that the organisms, as a result 
of these movements, soon leave the sphere of influence of the 
substance in question. This effect is termed by Garrey “ chem- 
okinesis’’; it is analogous to that which I have called “negative 
Chemotaxis" in Paramecium. The chief portion of the paper 
is devoted to determining the relative strength of various chem- 
icals in causing this reaction, and the exact factors in the solu- 
tions that produce the effect; interesting and valuable results 
are here brought out. 
In certain organic acids (acetic, butyric, lactic) and their 
salts Garrey found the flagellates to form aggregations, as Par- 
amecium does in solutions of CO2 and acids of all sorts ;? 
! Garrey, Walter E. The Effects of Ions upon the Aggregation of Flagellated 
Infusoria. Amer. Journ. of Phys., vol. iii, pp. 291-31 5. 
? Owing to the failure of his attempts to repeat my experiments with solutions 
of CO, and inorganic acids, Garrey denies my results with Paramecia. His fail- 
ure was unquestionably due to neglect to fulfill the necessary experimental condi- 
tions. I have never known the experiments to fail when properly carried out. 
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