Investigation of the microflora associated with the earthworm

Abstract

It is widely accepted as an established fact that the activity of earthworms promotes soil fertility. While the mechanisms responsible for this general effect are only vaguely understood, it is reasonably certain that micro-organisms will participate in most of the processes that involve transformations of organic substances. The literature provides little information concerning the gut microflora of the earthworm or of the effect of earthworms on the micro-organisms of the soil. These problems have been investigated only by Bassalik (1913). St8ckli (1928), Dawson (1947) end Day (1950). in no case did the work penetrate deeply into the subject. The investigation to be described here had as its principal objective a study of the changes that occur in the microflora when soil passes through the alimentary tract of the worm. Information on this question is desirable for the reason that many tons of soil per acre may be passed through earthworms in the course of a year (Evans, 1948)* Another objective was the investigation of any changes in the soil microflora that the worm might produce by other means, as for example by its secretion of slime. The lack of previous experimental work made it necessary, as an initial step, to establish satisfactory methods of Investigation. As it is not possible to examine the contents of the alimentary tract of the earthworm without contact with its coelomic fluid, it was also necessary to deter* {mine the nature of the microflora of the coelom. In the limited time available, an attempt has been made to provide a preliminary investigation which may serve as a basis for future studies of these problems.