β Scribed by Studier, Eugene H.
No coin nor oath required. For personal study only.
The ammonia concentrations in many day-roosts occupied by the guano bat, Tadarida brasiliensis, are frequently high enough to produce respiratory discomfort and distress and sometimes reach levels lethal to humans. Investigations were begun in an attempt to elucidate some of the mechanisms of ammonia tolerance of the guano bat. Initial findings show that the blood pH of the guano bat is 7.66 and remains constant during extended exposure to a high concentration of atmospheric ammonia. The efficiency of respiratory filtration of ammonia was measured by noting the increase above normal in total blood nitrogen and non-protein nitrogen after exposing the blood in vivo and in vitro to highly ammoniated air. From the difference in these two values the amount of ammonia filtered by the respiratory tract was obtained. At ammonia levels of 3,000 parts per million in the air, the bat removes 30-35% of this noxious gas; thus, the existence of an efficient ammonia filtering system is indicated. The filtering mechanism is probably dependent upon the mucous of the respiratory tract, and the filtering efficiency is a function of its rate of production and chemical nature. The observed in vivo increase in blood non-protein nitrogen resulting from exposure to highly ammoniated air may be attributed to ammonium ions. Ammonia is exhaled by the guano bat upon its return from highly ammoniated to normal air. Renal excretion of Gxed base is probably not an adaptive feature contributing to the high degree of ammonia tolerance exhibited by T. brasiliensis.
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