132 MICROSCOPY FOR BEGINNERS. 



from the water. If the plants among which they con- 

 ceal themselves and search for food are lifted out of the 

 pond, the water running off washes away all the animals 

 you are seeking. So take the water in the dipper, or 

 float the plants into the bottle, which should never be 

 entirely filled, nor corked for any length of time. The 

 Infusoria are very fond of fresh air ; they rapidly ex- 

 haust 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 dish so as to have a wide sur- 

 face exposed to the atmosphere. The plants as well as 

 the Infusoria do 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 creat- 

 ures that avoid the shadier parts. To obtain those that 

 are free-swimming, that is, those that are never perma- 

 nently adherent to the leaflets of plants nor the fila- 

 ments 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 are 

 ready for study. Those attached to plants can be found 

 only by cutting off a small piece of Myriophyllum or 

 other water -weed and examining it under the micro- 

 scope. In these cases it is necessary to lift the piece of 

 weed from the water, but it can be moved gently, and 

 at once placed in a drop ready for it on the slide. Some 

 of the most interesting kinds of Infusoria are found ad- 



