THE AMERICAN 



MONTHLY 



MICROSCOPICAL JOURNAL 



Vol. IV. 



Boston, July, [883. 



No. 7. 



The Action of Taiiiiiii on the Cilia 

 of Infusoria. 



At a meeting of the Royal Micro- 

 scopical Society, on March i4fh, Mr. 

 Henry J. Waddington read a valuable 

 article, from which we have condensed 

 the following summary : In trying 

 the effect of various chemicals upon 

 infusoria — principally Parameciii7n 

 aiircUa — a solution of tannin, or tan- 

 nic acid, was used, which immediately 

 rendered the cilia visible, without 

 manipulating the light. 



On placing a drop of water contain- 

 ing the paramecia upon a slide, with a 

 minute quantity of solution of tannic 



acid and causing the liquids to flow 

 together, the instant the paramecia 

 approach the mixed fluids their motion 

 is arrested. The cilia then gradually 

 become more and more distinct, until 



the body of the animalcule seems en- 

 tirely surrounded by them. 



If the solution of tannin is too weak 

 the cilia are not immediately arrested 

 in their motion, and they then appear 

 more or less crossed and crumpled as 

 in fig. 21 ; but if the solution is of the 

 the proper strength they stand out 

 straight, as in fig. 22. 



Fig. 22. 



It is recommended by the author 

 to examine the infusoria with a parab- 

 oloid, after this treatment. 



The tannin, unless the solution is 

 quite strong, does not instantly kill 

 the animals, for the contraction and 

 distention of the contractile vesicles 

 may be observed for some time. 



The solution of tannin used is made 

 by dissolving one part of tannin acid 

 in four parts of glycerin. 



Mr. VVaddington also uses a solution 

 of sulphurous oxide gas * in alcohol. 



A minute quantity of the alcoholic 



[The method of preparing this gas can be 

 found in any treatise on chemistry; the old 

 name of the compound is sulphurous acid gas. 

 —Ed.] 



