infus6ria. 133 



One of the best ways in which to collect the little 

 creatures is to gather aquatic plants and Algae without 

 entirely removing them from the water. If the plants 

 among which the Infusoria conceal themselves and 

 search for food, are lifted out of the pond, the water 

 running off washes away many of the animals soiight. 



The Infusoria are very fond of fresh air; they 

 rapidly exhaust the oxygen in solution in the water, 

 dying quickly, and going to pieces almost as soon as 

 dead. Give them plenty of air in the collecting- 

 bottle, and -at home pour the gathering into a broad 

 vessel, so as to have a wide surface exposed to the at- 

 mosphere, the plants as well as the Infusoria doing 

 better in such quarters. They are also usually fond of 

 the light, and will soon make'their way to the side of 

 the vessel nearest the window, and the dipping-tube 

 put in at that side will often capture creatures that 

 avoid the shadier parts. 



To obtain those that are free-swimming, that is, 

 those which are never permanently adherent to the 

 leaflets of plants nor to the filaments of Algae, as many 

 of the most interesting are, they can be transferred to 

 the slide by the dipping-tube and the drop covered by 

 the thin glass, when they will be ready for study. 



Those attached to plants can be found "only by cut- 

 ting off a small piece of Myriophyllum or of other water- 

 weed and examining it under the microscope. Some 

 of the most interesting kinds of Infusoria are found ad- 

 herent to Ceratophyllum and to other plants with 

 finely divided leaves. Every part should be searched 

 with the microscope, especially the angles between the 

 leaflets. 



The bodies of the Infusoria are usually very soft 



