infus6ria. 145 



the tin dipper among the aquatic weeds, and after 

 several gentle turns and twists to loosen the plants 

 and to stir up the water about them, transfer the 

 dipperful to the bottle., and hope for the best. The 

 majority of microscopic animals may be collected in 

 this way better than in any other. The method is not 

 restricted to the Infusoria. 



Although most of these little aquatic creatures are 

 voracious feeders, and while some flourish in putrid 

 animal-macerations, the greater number seem to 

 avoid filthy places. A pond contaminated by offal or 

 by the refuse of the city's garbage, will not be a good 

 collecting-ground, unless the filth is greatly diluted. 

 Water that is offensive to the human being's sense of 

 smell will not as a rule contain many animals. A few 

 of a certain kind, those peculiarly and emphatically 

 scavengers, will be there, but the collector will have a 

 better chance for success, at least so far as species are 

 concerned, in a sweet, clear-water pool where the 

 weeds are profusely growing, where the trees drop 

 their foliage in the autumn and shade the surface in 

 the summer; where the- lilies bloom, and their leaves 

 die and by their decay supply food to the invisible ani- 

 macules in the shallow depths below. 



A pocket-lens has been recommended as helpful in 

 collecting creatures for the microscopical aquarium. 

 Nothing could be more- useless. With few exceptions 

 they are all invisible to any but a comparatively high 

 magnifying power of the compound microscope. A 

 pocket-lens will not exhibit them. A few are, under 

 favorable circumstances, visible to the naked eye, but 

 these are few. The microscopist that desires the little 

 creatures must through experience know the favorable 



