TKKHAHIA AM) HALANXKD AQUARIA IN THE 

 LABORATORY. 



KLIZABETH L. THOMPSON. 



It is not tin- aim of this report to set fortli a mass of luw material. 

 It is. ratlier, an attempt to gather together into a eondensed and usable 

 form mueh scattered data on the subject of terraria and aquaria, includ- 

 ing the methods wliich have actually been tried out by the writer, and 

 to emphasize the value of this somewhat neglected source of information 

 in laboratory work. The needs for such a compilation and for simple 

 directions became apparent in an attem))t to introduce this subject into 

 class work in a limited time. It was found that the books available for 

 this work contained so much extraneous material and so many non- 

 essential details that they were almost useless for directive work. 



The value of the aquarium as a sort of "Zoological Garden" for 

 aquatic animals has long been recognized by museums for demonstra- 

 tion purposes but not fully appreciated from tlie educational point of 

 view in laboratories and schools. The ease of construction and main- 

 tenance of botli tlie balanced aquarium and tlie terrarium }iuts them 

 witliin the reach of every laboratory, every school and even every home. 

 For the aquarium running water is not necessary. The tank should not 

 be considered a cage, but rather a limited "liabitat" for the animals 

 which it contains and this liabitat should be made as nearly like the 

 natural habitat of tliese animals as possible. This attempt to recon- 

 struct the natural environment will necessitate the introduction of water 

 plants, a medium of sand and gravel for their roots and conditions of 

 light and temperature suitable for their growth. The plants and ani- 

 mals each contribute certain elements necessary to tlie other, the 

 "balance" works out automatically and little further attention is x'equired. 



The aquarium in the laboratory has almost unlimited possibilities for 

 the study of acpiatic life and the materials for its construction and 

 population are usually readily available. A medium sized tank, that is, 

 one containing from two to three gallons of water, or a still smaller tank, 

 rectangular, square or cylindrical (never globe shaped) will be foinid 

 most satisfactory. It should be of white glass, not green. Battery 

 jars of various sizes or even fruit jars of the straight sided type make 

 excellent tanks. The cylindrical jar has the disadvantage of making 

 the animals and plants within appear somewhat distorted when viewed 



intli Mich. Acad. Sci. Kept., 1917. 



