On the Function of Haemoglobin in Chironomus

Abstract

1. At 17°C. the oxygen consumption of Chironomus larvae shows little diminution when the oxygen concentration in the water decreases from 7.5 c.c. per litre (air saturation) to about 3 c.c. per litre. Below 3 c.c. per litre a further decrease in oxygen concentration causes a falling off in oxygen consumption. 2. At 17°C. the oxygen consumption of Chironomus larvae whose haemoglobin has been converted to carboxyhaemoglobin is as great as that of normal animals from air saturation down to 3 c.c. per litre. Below this point the oxygen consumption is less than that of normal animals. 3. It follows that at 17°C. the haemoglobin of Chironomus larvae from well aerated water does not function in oxygen transport at air saturation, but only at oxygen pressures below 3 c.c. per litre. 4. Some observations of the habitat of the larvae show that they can live in situations where oxygen concentrations of less than 2 c.c. per litre persist for periods of at least 16 consecutive hours. The larvae are also to be found in situations where the oxygen concentration is high.