. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. EFFECTS OF OXYGEN LACK ON PARAMECIUM 351 vival, really achieved strictly anoxic conditions; and it is clear that Paramecium can make some use of oxygen at partial pressures below 1 mm. It also seems doubtful whether Juday (1909) would have de- tected oxygen in such low concentrations in the bottom waters of Lake Mendota (Wisconsin), where he claimed that Paramecium lived an- aerobically. However, it remains possible that Paramecium might be found to survive without oxygen for longer periods under experimental conditions if i
. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. EFFECTS OF OXYGEN LACK ON PARAMECIUM 351 vival, really achieved strictly anoxic conditions; and it is clear that Paramecium can make some use of oxygen at partial pressures below 1 mm. It also seems doubtful whether Juday (1909) would have de- tected oxygen in such low concentrations in the bottom waters of Lake Mendota (Wisconsin), where he claimed that Paramecium lived an- aerobically. However, it remains possible that Paramecium might be found to survive without oxygen for longer periods under experimental conditions if it were supplied with suitable food. Slight discrepancies between the results of other workers may be ascribed to variations in the excellence of the oxygen " lack," possibly to the use of several different species, and particularly to variations in the state of nutrition of the organisms. This latter condition was stressed by Putter (1905), and probably accounts for the beneficial effect of stirring the culture. There is clearly some adverse influence in phosphate buffer which a normal healthy Paramecium can withstand in air, but which success- fully operates against a starved Paramecium in air or against a well-fed one in absence of oxygen. The constriction of the anterior end of the organism and the blistering just before death are probably the result of a violent contraction of the myonemes. They were found to occur even when the organism was in M/20 lactose solution, and it is there- fore unlikely that they can be attributed to osmotic uptake of water by the organism. A somewhat similar effect has been seen in Paramecium subjected to an electric current (see Kalmus, 1931). The phosphate buffer, either directly or indirectly, hastens the time for the myoneme contraction. It seems probable that the harmful effect of this buffer is due to a lack of balance of ionic concentrations, although this matter has not yet been investigated in detail. Whereas cyanide in very l
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Keywords: ., bookauthorlilliefrankrat, booksubjectbiology, booksubjectzoology
