PHYSIOLOGICAL OBSERVATIONS UPON A LARVAL EUSTRONGYLIDES

II. THE AEROBIC RESPIRATION

1. Variations between 0 and 1.5 per cent NaCl in the medium had no influence upon the oxygen uptake of a larval Eustrongylides, but concentrations between 2 and 4 per cent were definitely toxic.

2. The oxygen uptake (140 cu. mm. per gram per hour) was greater than that found in Ascaris, but smaller than that reported for Setaria, hookworm or Trichinella larvae.

3. The oxygen uptake of nematode species of very different sizes remains more constant if calculated on the basis of weight rather than surface.

4. During a week's starvation at 37° C. the oxygen consumption decreased to about half the initial value.

5. The mean respiratory quotient of aerobically kept worms was in all series slightly above one, but no aerobic excretion of organic acids could be demonstrated with the methods employed.

6. In an aerobic period following an anaerobic period of 16 to 18 hours duration, the worms repaid about 30 per cent of the incurred oxygen debt and retained a considerable amount of carbon dioxide.

7. Freshly isolated worms, on the other hand, showed only a trace of excess oxygen consumption and carbon dioxide retainment. It is therefore concluded that the animals inside their cysts in the fish lead an almost purely oxidative life.