Water that results from the oxidation of organic materials by living organisms is termed “metabolic” or “oxidation” water, and has long been recognized as a component, sometimes an important one, of the total water income of animals (Babcock, 1912). The complete oxidation of a fat such as tripalmitate to carbon dioxide and water yields about 107 g water for every 100 g fat while a similar weight of the carbohydrate glucose yields 56 g, and of protein (taken to urea) about 40 g water (Table 31). Thus an animal while fasting and metabolizing fat reserves could gain weight were it not for loss of water by transpiration and of other materials by defaecation. It follows that for arthropods living in dry surroundings such as stored grain where there is no free water and the water content of the food is low (Chap. 7.A.), metabolic water may be very important, as was recognized early on by Buxton (1930), Mellanby (1932 a, c), Fraenkel and Blewett (1944) and others.
KeywordsWater Balance Liquid Water Content Metabolic Water Radiation Load Thoracic Temperature
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