THE SLIPPEE ANIMALCULE 11 



Use the same apparatus as for Amceba, with one per 

 cent, solution of chloral hydrate and one per cent, solu- 

 tion of osmio acid additional, also a saucer and a piece 

 of pasteboard. 



Method of Examination. — The same as for Amoeba. 

 Paramecium, is an exceedingly active animal except 

 when feeding, hence it is well to have a supply of decay- 

 ing vegetable tissue in the drop which is being exam- 

 ined. Specimens may be brought to rest by allowing 

 the water between the slide and the cover-glass slowly 

 to evaporate, or they may be caught in the meshes of 

 a thin layer of cotton-wool which may be spread out on 

 the slide. As the cover settles down the animal will 

 be caught and held fast. Care must be taken not to 

 allow the cover to crush the specimen. This may be 

 avoided by adding from time to time at the edge of the 

 cover small drops of water just sufficient to make up 

 for the loss by evaporation. Or, a drop of one per cent, 

 solution of chloral hydrate or of one per cent, acetic 

 acid may be added to the drop containing the specimen ; 

 either of these reagents, however, will kill the speci- 

 mens in the course of a few minutes. They may be 

 killed in condition satisfactory^ for examination by plac- 

 ing the slide with the drop of water downward over the 

 mouth of a bottle containing a one per cent, solution of 

 osmic acid. Exposure to the fumes of this acid usually 

 causes the death of Pa/ramecium in two to five minutes. 



It is best to examine the active animals before at- 

 tempting to use the reagents. 



MOBPHOLOGT 



a. Shape. — "What is the shape when the animal is at 

 rest ? Does it change during locomotion ? Com- 



