Observations made by various workers over many years have indicated more or less clearly the probability that there is in this country a race of the stem eelworm, Anguillulina dipsaci, capable of attacking oats, field beans, onions, rhubarb, parsnips and certain common weeds. One of the earliest records bearing on this is that provided by Bos (1892) who cited information, supplied to him by Miss Ormerod, which showed that field beans might be seriously attacked by the parasite when grown after oats which had suffered from “tulip-root”. Many years later Johnson (1936a & 1940) reported failure of beans from eelworm attack following “tulip-root” oats in fields in Yorkshire and showed the significance of common chickweed and cleavers as reservoir hosts on which the parasite can live in the absence of susceptible farm crops. In another paper (1936) he showed that A, dipsaci associated with crown-root of rhubarb is interchangeable between rhubarb and oats in both of which it is capable of setting up disease symptoms. In his 1940 paper this investigator showed that A. dipsaci from rhubarb readily infests oats and common chickweed and also transfers to beans and, further, that the parasite from both oats and beans is infective to cleavers and common chickweed and back from both these weeds to oats and beans.

The pathology of the infection in the trout of Poulaphouca Reservoir is described.

An annual mortality was found to occur in the trout during the summer months. This was caused by peritonitis which is attributed to plerocercoids becoming active as a result of the increase in temperature.

It is demonstrated that the infection in trout is probably of a secondary nature resulting from their feeding on sticklebacks primarily infected from the Copepod hosts.

The nematodes described below are in the collection of the Department of Parasitology, London School of Hygiene and Tropical Medicine and I am much indebted to Dr. R. T. Leiper, C.M.G., F.R.S., who allowed me to examine them and who gave me considerable help and encouragement throughout the work.

A method is described by means of which trichostrongylid spicules are separated from the surrounding soft tissues and their examination made easier. NaOH and KOH are the most satisfactory substances for this purpose, though both substances eventually act on the chitin of the spicules themselves, causing distortion. The reaction takes place at a temperature of 37°C. with reasonable speed. Spicules of Ostertagia can also be freed satisfactorily by this method but those of Nematodirus are quickly affected by the alkali, with consequent distortion.

Davainea madagascariensis is a rather rare human parasite, there being less than a dozen cases on record. It was originally described from children in the Comoro Islands by Davaine in 1869 under the name Taenia madagascariensis and has since been recorded from a wider area stretching from Madagascar and the neighbouring islands through Siam to the Philippine Islands in the Pacific Ocean. Recently some cestode segments were sent to Dr. R. T. Leiper, C.M.G., F.R.S. They had been passed in the stool of a human patient in S.E. Africa. They have now been identified as gravid segments of Davainea madagascariensis and this would seem to be the first record of the species from the mainland of Africa.

Although outbreaks of trichinosis in Great Britain have been sporadic, the present investigation shows the incidence of Trichinella spiralis in man in Southern England to lie between 7.9% and 13.7%, the average incidence being 10.8%. The condition of the larvae, either free or in thin- or thick-walled cysts recovered by the “digest” technique, indicated that the infections were of varying ages, from recent to those of many years standing. In six cases there was definite evidence of the presence of both recent and old infections.