Democratic Sentinel, Volume 19, Number 14, Rensselaer, Jasper County, 12 April 1895 — HOW FISH BREATHE. [ARTICLE]

HOW FISH BREATHE.

Require but the Minimum of Oxygen to Keep Up Temperature. The gilte of the tish are situated at the back part of the sides of the head, and consist of a number of vascular membranes, which are generally arranged in double, fringeiike rows, attached to the parts by the base only. In some cases these membranes are feather-shaped; in others, mere folds attached to the' sides of the gill cavities. The fish is a eold-blooded animal; that is to say, its temperature is seldom more than a degree or two higher than the water in which it lives. This being true, the creature needs but a very small amount of bxygen to keep the blood at a temperature sufficiently high to sustain life. This oxygen is supplied to the blood of the lish by respiring large quantities of water, or, rather, drinking large quantities of water, and respiring the air separated from it by the gills. This explains why a lish cannot live in a tank of water which has been sifted through the gills time and time again any better than a human being or other animal can in air that has been deprived of all its oxygen by being taken into lungs and expelled without being aerated. Fish that die in the stale waterof aquariums may be properly said to drown, because they perish for want of air, the same thing which occasions death by drowning in man and other lungbreathing animals.