Studies on the physiology of the nematodes of the alimentary canal of sheep

Abstract

An investigation was made of certain aspects of the physiology of nematodes from the alimentary canal of sheep.Cellulose digestion has apparently no effect on the nematodes.The composition and concentration of a physiological saline solution suitable forOstertagia circumcincta—and possibly for the other species—was determined.The effect of acidity on the intestinal worms showed that they could not live in the abomasum because the acidity in this chamber would be too great.O. circumcinctacould not inhabit the stomach of horses, and carnivores, or the abomasum of cattle, in all of which the acidity reaches a level lethal to this species.A graph is given showing the distribution of the nematodes in the small intestine of the sheep. After a study of the effect of bile salts on the different species its influence in determining this distribution is discussed.A discussion of the evidence relating to the food of nematodes of the alimentary tract led to the conclusion that even species with rudimentary buccal capsules might suck blood; on the other hand, the results from the benzidine tests and spectroscopic examinations indicate that the haemoglobin demonstrated in nematodes is synthesized by them.It was shown thatO. circumcinctadoes not probably feed on abomasal contents. Bacterial difficulties hampering these experiments were overcome by using an apparatus whereby the contents of the abomasum could be percolated over the worms. The latter had been surface-sterilized with acriflavine solution.All attempts to feed the nematodes on serum, defibrinated blood, and blood digests failed. Bacteria again constituted a difficulty, but it is suggested that the failure is not entirely due to them, and that perhaps the tissues of the host must be incorporated into the media.