File:Aquatic life (1917-1918) (19559454450).jpg

Title: Aquatic life
Identifier: aquaticlife319171918baus (find matches)
Year: 1917-1918 (1910s)
Authors: Bausman, Joseph E
Subjects: Aquariums; Fish culture
Publisher: Philadelphia : J. E. Bausman
Contributing Library: Harvard University, Museum of Comparative Zoology, Ernst Mayr Library
Digitizing Sponsor: Harvard University, Museum of Comparative Zoology, Ernst Mayr Library

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Text Appearing Before Image:
Aquarium BiocKemistry EDGAR R. WAITE. F. L. S. Presiaent, Soutn Australian Aquarium Society
Text Appearing After Image:
A Pile of Goldfisk Ashore and (right) others Gasping at the Surface of the Water Photographs hy the Author -» Most people know that water is com- posed of two gases, hydrogen and oxy- gen, in the proportion of two to one. They also know that fishes breathe in oxygen to regenerate their blood, and they imagine, perhaps not unnaturally, that the fishes obtain it from the combi- nation. This they cannot do, for as soon as the correct proportion of the two gases is disturbed, water no longer exists. We must, in the first place, appreciate the difference between the chemical ex- pressions "mixture" and "combination." Atmospheric air is formed of a mixture of two gases, nitrogen and oxygen, and we can vary the normal proportion (of about 79 to 21), within certain limits, without destroying the use of the mixture for respiratory purposes. Water, on the other hand, is produced, not by a mix- ture, but by a chemical combination of two gases in certain definite proportions, as already mentioned, which cannot be upset in the ordinary course of events; if the proportions are changed, say by means of electricity, resulting in the ab- straction of a certain amount of oxygen, then twice that quantity of hydrogen is also set free, and a corresponding meas- ure of water, as such, is destroyed. It will be evident, therefore, that fishes can- not breathe the oxygen which is a con- stituent of the water in which they live. Water has the property of absorbing and retaining a certain amount of free oxygen, this amount varying under dif- ferent conditions, especially of tempera- ture, the warmer the water the less it can hold. Fishes cannot, therefore, live in water that has been recently boiled, be- cause most of the breathable oxygen has been driven ofT. This boiled water, while cooling, will gradually reabsorb atmos- pheric oxygen, and the greater area of water exposed the more rapidly will ab- sorption take place. Hence the process

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