Studies in the metabolism of protozoa

THE nitrogenous metabolism of the protozoa has hitherto been much more extensively studied from the anabolic than from the catabolic aspect. This is probably due to the fact that information regarding nitrogenous food requirements is likely to facilitate culture of the protozoa, whilst the search for metabolic end-products is greatly hampered by the complexity of the cultural media which it is usually necessary to employ. A discussion of this difficulty and of the methods used in this work to minimise its effects is given later in this paper.