The material forming the basis of this paper consists of the two fungi, Catenaria anguillulæ Sorokin and Rhizophidium carpophilum Zopf, which were found parasitic on the eggs of Dibothriocephalus latus in the Helminthology Department in March, 1927. The stool containing the eggs had been washed in laboratory tap water and this was evidently the vehicle of the fungus infection. A sediment obtained from one of the water tanks from which the laboratory is supplied was found to contain infusoria, rotifers and other forms likely to act as hosts for the fungi, and that this was the source of the original infection was proved on more than one occasion by placing some of the sediment in a petri dish along with some uninfected eggs of D. latus, when a new infection of both the fungi appeared in the eggs.

In the following paper the fungi are described and an account is given of some experimental work that was carried out with a view to determining the possibility of employing such parasites as a control measure in helminthiasis.

In a previous publication the morphological characters of a strain of H. schachtii specialised on the potato in Lincolnshire were discussed. The size and shape of the brown cysts, size of the eggs and first stage larvæ and the general characters of the adult males of this strain were compared with those of a strain attacking potatoes in Rostock, Mecklenburg, for which the specific name H. rostochiensis was suggested by Wollenweber 1923.

Considerable dimensional variations were found to exist in the Lincolnshire strain, and a study of the literature on the morphological characters of H. schachtii specialised on sugar-beet and oats, showed equally wide divergencies between the findings of different workers. A certain amount of preserved material of infected roots of beet and oats being available to the writer, as many developmental stages as possible were extracted from these, on which similar morphological studies were carried out. Thus a fairly complete comparative survey of H. schachtii specialised on beet, oats and potatoes was completed, and the morphological variations between the strains were found to be insufficient to justify the separation of the strain specialised on potato from those on beet and oats. The name H. rostochicnsis was, therefore, deemed a synonym for H. schachtii.

In 1924, Morgan visited South Lincolnshire to investigate the part played by the potato-root eelworm (Heterodera schachtii) in the serious failure of the local potato crop: a note on the investigation appears in this Journal (1925, p. 185). A second visit was made in 1925, as a result of which certain conclusions regarding manuring and the rotation of crops were put forward (this Journal, 1926, p. 49). Towards the end of 1925 the second writer (Peters) made a hurried survey with the object of seeking a possible correlation between the distribution of eelworm cysts and the hydrogen ion concentration of the soil. Such a correlation was actually demonstrated (this Journal, 1926, p. 87) in the case of a selected field for which Morgan had complete data of cyst-counts. The question thus arose as to whether any clear correlations should be shown to exist between the three factors: concentration of cysts, pathological condition of the crop, and reaction of the soil. In other words, was the eelworm associated with the damage? and was it controlled (and therefore controllable) by the effective acidity of the soil? To decide these questions might be a matter of considerable importance, particularly if the eelworm was found to be responsible for the damage, for affirmative answers would open the way to effective treatment, by the adequate liming of soils for instance.

The nematode has been known as a serious parasite of potatoes for a number of years. The disease produced by it was first described in Germany by Kühn (1888) under the name of Wurmfäule. Shortly after this Ritzema Bos (1892) confirmed and amplified Kühn's account and carried out an experimental investigation on the disease. The present writer Goodey (1923) gave a short résumé of this earlier work and an account of the occurrence of the disease on potatoes in the Holbeach area of Lincolnshire. Buckhurst (1925) also reported the results of certain successful pot experiments in which potatoes were infected by growing in soil containing diseased tuber material. Finally, an important paper by Quanjer (1927) has appeared in which he deals with the occurrence of the disease on potatoes at Wageningen, Holland, and shows that the physiological race of worms attacking potatoes there occurs naturally on certain wild plants in the pastures and is capable of attacking a wide range of host plants both cultivated and wild. He also discusses the mode of entry of the parasite into the host and the nature of its action on the plant tissues.

As Looss has shown, the larvæ of Ancylostoma can infect a suitable host by penetrating the healthy skin. If we place the infective material on the surface of the skin, after a short time we find the larvæ in the subcutaneous tissue. The same behaviour is shown by the filariform larvæ of Strongyloides siercoralis, which provide more convenient material for examination, because they can be collected very easily in pure culture and free from fluid by the special culture-method described by me (1924), the principle of which depends on the well-known fact that the filariform larvæ of Strongyloides and other nematode larvæ, accumulate in the form of white filaments of several millimetres in length (fig. 3), each consisting of thousands of individual larvæ, on little prominences in their vicinity, all being guided to similar places by the same sets of “tropisms” (Fülleborn, 1924).

Anguillulina has been revived by Baylis and Daubney (1926) as the correct generic name for those worms which for many years have been considered as belonging to the genus Tylenchus, at least by most specialists on nematodes and plant-pathologists. Gervais and van Beneden on pp. 101 and 102 of the second volume of their work Zoologie Médicale, published in 1859, gave a brief account of the eelworm parasite of wheat causing “purples” or “cockles” and that found by Kuhn in 1858 in the heads of the fuller's thistle, teasle, both of which they designate as Anguillulines (Anguillulina) as follows:—Anguillilina tritici and Anguillulina dipsaci.

It may be pointed out, in passing, that they were not consistent in the use of the word, for at the end of the description of A. dipsaci they spell it as Anguillula not Anguillulina. This may, however, perhaps be regarded as an unintentional slip or a printer's error. Bastian's paper in which first the name Tyleenchus and then Tylenchus is applied to members of this genus appeared in 1865 and he designated Tylenchus davainii as type species of the genus in a letter to Stiles dated March 22nd, 1904, vide Stiles and Hassall (1905).

For two years, from June, 1927, the writer held a Research Scholarship in Sanitary Science from the Grocers' Company, the terms of reference including a biological study of the fauna of sewage-treatment plants. Special attention was paid to the free-living nematodes since in mere quantity they form an important section of the fauna in many treatment units, and they have been much neglected as a group in comparison with the protozoa and bacteria.

Owing to the failure of the potato crops in South Lincolnshire in areas where the eelworm Heterodera schachtii was known to occur, investigations were undertaken by this Institute to determine to what extent the nematode was responsible for the losses incurred, and to discover some method for its control. This work was begun by Dr. D. O. Morgan in the autumn of 1924. In order to gain a general knowledge of the natural conditions under which the nematode occured, and to obtain some indication of the most promising lines on which fundamental research might be carried out, extensive field observations were made. By this meand much data was accumulated which has been of great service in the carrying out of later laboratory adn field studies.

The plant parasitic nematode, Tylenchus dipsaci Kühn, commonly known as the stem eelworm, or alternatively when occurring in narcissus, the bulb eelworm, is a major pest of a wide range of cultivated plants. Accurate knowledge concerning the detailed life-history of the nematode is still of limited extent, despite the large numbers of workers who, throughout Europe and more recently North America, have devoted much time to a study of the subject. In particular it is clear that much remains to be learned concerning the “biologic strain” theory. Investigators, probably without exception, agree that a large number of, so-called, biologic strains of the worm occur. Each of these strains, while morphologically identical with the others, appears to be restricted more or less rigidly to a particular species of host plant.

In the course of work undertaken in the preparation of the experimental field plots at Winches Farm it has been of interest to ascertain something about the nematode fauna of the place, especially that occurring in certain heaps of manure made at the farm and afterwards used on some of the plots. With regard to the worms recorded from sheep droppings collected from pastures these were obtained in Baermann extractions, set up by a colleague, in attempts to collect larvae of parasitic nematodes harboured by the stock. It became necessary for purposes of differentiation to determine the naturally occurring free-living nematodes which were found in great abundance. The worms described in the following pages have been encountered in the course of these investigations. Some are new to science and about others very little has previously been known so that additional information on them is here made available.

The Potato Testing Station at Ormskirk, a branch of the National Institute of Agricultural Botany, has during the past season, been found to include considerable areas of land heavily infested with the eelworm Heterodera schachtii. This discovery was made subsequent to the failure of some of the potato crops, which, in the course of the normal rotation practised at the station, happened last season to be grown on the affected areas.

Since the discovery of the plant-infesting nematode Heterodera schachtii Schmidt, 1871, many infections of this nematode occurring in different countries on a wide range of host-plants have been studied. Owing to the serious agricultural losses occasioned by this pest, efforts have been made, both in Europe and in the United States, to determine the range of plants which are susceptible to infection. Lists of plants susceptible and non-susceptible to attack have been drawn up by various workers, and these have comprised not only plants of economic importance, but also weeds which might serve as an important means of propagating the parasite. The abundance of contradictory evidence which appears in these lists is only explicable by Steiner's (1925) exposition of the hypothesis of biological or physiological strains. This work serves to emphasise the importance of crop rotation as a means of combating the parasite, more particularly when the nematode population constitutes a monophagous strain, i.e., one which has become highly specialised upon a single hostplant and has lost the power of readily attacking other species. Where a polyphagous strain occurs, the range of non-susceptible plants which can be used in the course of the rotation is greatly diminished, and, in such cases, the weeds occurring on the infected land may add an important complicating factor to the problem of eradicating the pest.

In 1927 Fairley Described in the Medical Journal of Australia an Intradermal Reaction in Human Schistosomiasis, Using as Antigen the Dried Powdered Livers of Snails (Planorbis Exustus), Infested with the Cercaria of Schistosoma Spindalis of the Goat, Dissolved in Saline. The standard dose adopted was 0·25 cc. of an 0·5 per cent, extract prepared from the dried powder, ground up in a mortar with 50 ccs. of normal saline solution (0·85%) and the resulting mixture thoroughly shaken by hand. It was then incubated for one hour at 37° C. Subsequently the extract was centrifuged, the supernatant fluid pipetted off and filtered through a Seitz filter (size 3) attached to a water pump. The filtrate, consisting of a clear coloured fluid is put up in ampoules of 0·5 cc. each and stored in an ice-chest.

In the microscopic examination of plant-parasitic and free-living nematodes it frequently happens that certain anatomical details stand out clearly whilst others remain obscure. Later examination of further examples of the same species, perhaps from a different source or at another season of the year, may reveal some of the previously obscure details with the result that structures which up to that time had been difficult to elucidate, are now seen distinctly in relation to their surroundings.

Muellerius capillaris was first described by Mueller in 1889 who placed it in the genus Pseudalius; it was transferred in 1907 by Railliet and Henry to their new genus Synthetocaulus. In 1927, Cameron, in his review of the family Protostrongylidæ Leiper, 1926, created the genus Muellerius to include this species; a description of this parasite together with figures of the adult and the larval stage commonly met with in the lungs and droppings of sheep and goats, is included in his paper.

M. capillaris inhabits the bronchioles and alveoli of the lungs of sheep and goats but is probably more often observed in the connective tissue of the lungs where it forms nodules of varying sizes. In heavy infestations these nodules are so close together that they appear as large greyish patches on the surface of the lung. The nodules eventually become calcified.

The vast majority of the helminthic parasites of man are represented among those animals which are in close contact with man, either by the same species or at least, by closely related forms. A very noticeable exception is Enterobius vermicularis. Possibly owing to its special life-history, it has become highly specialised for its human host and to find its closest relations, it is necessary to examine the forms found in primates.

The object of this paper is accordingly to systematise our knowledge of the oxyurid worms found in this group.

As Enterobius vermicularis is the most important of these, it has been found desirable to briefly re-describe its anatomy, followed by that of the related species, in apes, in monkeys and other primates.

During a visit to the island of St. Kitts, British West Indies, in 1928, I received from Dr. S. B. Jones for identification, a tapeworm which he had received from a young negress who had never left the island. The tapeworm was a specimen of Bertiella.

May I say, in the first place, how highly honoured I am by the invitation of the Royal Faculty of Physicians and Surgeons of the City in which I received my early medical training to give the sixth Finlayson Memorial Lecture.