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REARING AND COLLECTING ANIMALS 473 



'Bladderwort, Utricularia (several species). 

 'Water-starwort, Callitriche (several species). 

 'Watercress, Nasturtium officinale. 



'Stoneworts, Char a and Nitella (several species of each). 

 'Frog-spittle or water-silk, Spirogyra. 

 'A small quantity of duckweed, Lemna, placed on the 

 surface of the water adds to the beauty of an aquarium. 



"When it is necessary to add water to an aquarium on 

 account of loss by evaporation, rain water should be used to 

 prevent an undue accumulation of the mineral-water held 

 in solution in other water." 



Making collections. Much is to be learned about ani- 

 mals by "collecting" them. But the collecting should be 

 done chiefly with the idea of learning about the animals rather 

 than with the notion of getting as many specimens as possible. 

 To collect, it is necessary to find the animals alive; one learns 

 thus their haunts, their local distribution, and something 

 of their habits, while by continued work one comes to know 

 how many and what different kinds or species of each group 

 being collected occur in the region collected over. Collect- 

 ing requires the sacrifice of life, however, and this will always 

 be kept well in mind by the humane teacher and pupil. 

 Where one set of specimens will do, no more should be col- 

 lected. The author believes that high-school work in this 

 line should be almost exclusively limited to the building up 

 of a common school collection. Let a single set of speci- 

 mens be brought together by the combined efforts of all the 

 members of the class, and let it be well housed and cared for 

 permanently. Each succeeding class will add to it; it may 

 come in time to be a really representative exhibition of the 

 local fauna. 



The high-school collection should include not only adult 

 specimens of the various kinds of animals, forming a system- 

 atic collection, as it is called, but also all kinds of specimens 

 which illustrate the structure and habits of the animals 

 in question and which will constitute a so-called biological 

 collection. Specimens of the eggs and all immature stages; 

 dissections preserved in alcohol or formalin showing the ex- 



