242 THE AMERICAI^ MONTHLY [October, 



depend upon the kinds sought. Some are found only in the ooze at 

 the bottom of many pools, while others float freely at or near the sur- 

 face. The under surfaces of partially submerged boards or branches 

 are favorite habitats of polyzoa, sponges, and other beautiful and inter- 

 esting organisms. Some affect the shade, while others are scarcely to 

 be found except in warm and sunny spots. A little experience will 

 soon teach one the favorite haunts of the more common microscopic 

 plants and animals, and the acquiring of this experience is no tedious 

 drudgery. 



It is a remarkable fact that micro-organisms in general and the deni- 

 zens of ponds and ditches in particular are wonderfully cosmopoli- 

 tan. The microscopist travelling in Asia, in Africa, in America, or in 

 Australia, if he " takes a dip" from some wayside pool, will be almost 

 certain to find forms identical with or very similar to those with which 

 every reader of European microscopical literature is familiar. We 

 have every reason to believe that nearly all the wondrously beautiful 

 inhabitants of the microscopic aquatic world are to be found in our 

 streams and pools ; and yet such objects as Stephanoceros^ Hydrodic- 

 tyon^ Clathr^ulina^ Pectinatella^ and Volvox are still unknown to 

 California microscopists. This is a deplorable and rather mortifying 

 fact, but on the other hand the knowledge that such prizes are awaiting 

 the earnest explorer should stimulate us in the search. 



The most admirable monographs on microscopical subjects we pos- 

 sess are those devoted respectively to the Rotifera, the fresh-water 

 sponges, the Rhizopods, the Infusoria, the Entomostraca, the fresh- 

 water Polyzoa, the Desmids, the Diatoms, and other fresh-water algas, 

 all denizens of ponds and ditches. Besides the splendid treatises on the 

 foregoing classes, " Pond Life" has been made the subject of several 

 popular works of low price but good quality. The best of these is 

 "Microscopy for Beginners," by Dr. A. C. Stokes. 



A pleasant feature of the study of pond life is the facility with which 

 material for work can be obtained and preserved. The contents of a 

 few small vials may be used for stocking several small aquaria, which 

 need be nothing more elaborate than ordinary tumblers or goblets. A 

 little experience here will teach one how to avoid over-stocking with 

 vegetable life and preserve an even balance with the animal. It will 

 only be necessary to add a little fresh water from time to time, to make 

 up for evaporation, to preserve the inhabitants for weeks or months. 

 These miniature aquaria should have plenty of daylight, but very little 

 direct sunlight. 



Mr. Breckenfeld urged his hearers to make an occasional collecting trip 

 in search of the interesting organisms with which our fresh-water lakes, 

 ponds, and streams are teeming. It will furnish an inexhaustible store- 

 house, from whose supplies one can always draw abundant material for 

 recreation or study. The most of us, he said, are busy men, and the 

 day's duties are often both wearying and worrying. Here is a chance 

 for genuine rest, for real recreation. As one sits in a cozy room, 

 by the soft light of a shaded lamp, and sees in the bright circle of the 

 microscope's field of view the fascinating drama of miniature life there 

 presented ; as one watches the sweep of the beautiful Floscule' s wh^aX^ 

 and the mysterious procession of granules in the little Desmid's cell, 

 our own worries and troubles seems to diminish — the pleasant hours 

 glide swiftly along. 



