A NOTE ON THE CHEMOTAXIS OF OXY- 

 TRICHA AERUGINOSA. 



GEORGE WAGNER. 



Oxytricha csruginosa, Wrzeniowski, is one of the Hypotricha 

 occurring rather irregularly in laboratory cultures. Cultures of 

 it, so far as my experience goes, are quite characteristic in the 

 fact that they are distinctly brown in color, and decidedly more 

 alkaline than the average cultures of Paramecium. 



Jennings and Moore 1 found that this organism differed from 

 the congeneric Oxytricha fallax by forming spontaneously dense 

 aggregations like those of Paramecium. On the other hand they 

 found that unlike Paramecium it was not positive to carbon diox- 

 ide or indeed to any acid. They found that if both forms were 

 mounted on the same slide according to Jennings's now well- 

 known method, they would form separate aggregations, and that 

 the members of each species would pass freely through collections 

 of the other without being in any way detained. It is obvious 

 therefore that the cause of aggregation in the two forms must be 

 different. 



Several years ago I made an attempt, at the suggestion of 

 Professor Jennings, to learn somewhat more about this difference. 

 Unfortunately I was unable at that time to complete the work, 

 and I have not since been able to secure the necessary cultures 

 of Oxytricha. 2 It seems wise therefore to publish the results 

 so far obtained even though they may seem fragmentary. 



The spontaneous aggregations of Oxytricha on slides or even 

 in small open dishes are remarkable in being much more dense 

 than those of Paramecium, in being much more sharply circum- 

 scribed, and in expanding much less rapidly. In certain mixed 

 mounts of Paramecium and Oxytricha I found that, probably by 

 mere coincidence, both forms congregated in the same area. In 

 such cases at first the area inhabited by both was the same, ex- 



1 American Journal of Physiology, Vol. 6, 1902, pp. 242-243. 



2 For the rest of this paper Oxytricha is to be considered as meaning O. ceruginosa. 



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