A number of experiments was carried out on Polycercus lumbrici to induce evagination of the cysticercoid in vitro. The results indicate that in nature the containing cyst is ruptured by pressure and abrasion in the gizzard of the bird host and that evagination is induced mainly by the action of gastric juice followed by pancreatic juice, heat assisting the process by exciting vigorous movements in the larvae. By a process of elimination it has been shown that the effective agents are the pepsin in the gastric juice and pancreatin in the pancreatic juice. The latter probably causes contraction of the muscles of the wall of the caudal vesicle which forces out the scolex.

The monogenean (platyhelminth) skin parasite Entobdella soleae from the common sole (Solea solea) lays tetrahedral eggs. One of the 4 corners of the tetrahedron is a detachable operculum which is bonded to the rest of the egg-shell by cement. Most of this cement layer, beginning at the inner surface of the shell and running through almost to the outer surface (a distance of about 2 μm), is more or less uniform in thickness (30–38 nm), or tapers slightly. About 345 nm from the outer surface the cement layer narrows abruptly to about 10 nm. The cement is exposed on the inner surface of the shell, but in most eggs a layer of shell about 10 nm thick covers the narrow outer region of the cement layer. When experimentally perforated eggs were incubated with trypsin, the wide inner layer of cement was digested, but the narrow outer region initially remained intact. These observations are discussed in relation to the following (1) survival of the eggs during embryonic development, (2) hatching, (3) the ‘hinge’ often connecting the operculum to the empty egg-shell, (4) the rapid hatching that occurs in some other monogeneans.

The adenosine nucleotide and adenylate energy charge values of Nematospiroides dubius and Trichostrongylus colubriformis maintained in vitro under aerated and under near-anoxic conditions have been measured. Maintenance of the nematodes in both conditions had an adverse effect on their energy metabolism, but in comparing these effects it was found that the changes were more significant in those nematodes maintained in near-anoxic conditions and that the changes were more apparent in male nematodes. The smaller changes in the energy charge values of female worms, particularly N. dubius where there was no difference between worms in aerated conditions and those in near-anoxic conditions, were explained by the presence of eggs in the nematodes. At no time did the energy charge of nematodes in near-anoxic conditions fall below 0·50 but, whereas nematodes in aerated conditions were able to continue moving throughout the experiment, those in near-anoxic conditions stopped moving during the first 3 h. It is suggested that in the absence of sufficient oxygen the nematodes were able to maintain their energy charge above 0·50 by removal of AMP from the adenylate pool, resulting in the depletion of their total adenylate. The changes in the energy charge and behaviour of the nematodes are related to the survival of the nematodes in the oxygen-deficient environment which they inhabit in vivo.

While examining the strongyles of the fourth stomach of an ewe belonging to the Cambridge University Farm, which had been slaughtered for post-mortem examination, numerous male and female Ostertagia circumcincta (Strongylus cervicornis of MacFadyean) were found. A few specimens of Haemonchus contortus were also present.

In my “Revision of the Genus Stilesia” I had to leave several points in the anatomy of Stilesia globipunctata (Riv.) undecided, as the material I had of the worm was too macerated to allow of any definite conclusions. At the same time I pointed out, that the topography of the male canals as described by Stiles and Hassall disagreed with the conditions obtaining in Stilesia hepatica Wolffhügel, in other respects a very closely related species. The necessity for a re-examination of Stilesia globipunctata (Riv.) in order to decide whether the differences really exist, or whether they were supposed to do so, on account of the material examined by Stiles being rather macerated (loc. cit. p. 74), was all the greater as Stilesia globipunctata (Riv.) is the type species of the genus Stilesia. Through the kindness of Mr Littlewood, Chief Inspector of the Veterinary Department, I was able to obtain living examples of Stilesia globipunctata (Riv.) at the Cairo abattoir on Jan. 27, 1912. These worms have been fixed with Zeuker's solution, hardened and cut.

Agrippina bona, a gregarine parasitic in the gut of the larva of the rat-flea Ceratophyllus fasciatus, was first described by Strickland in 1912. His account of the sporulation of the gregarine was so curious that a more detailed investigation has been undertaken, which has given rise to the present paper. The work has been done in the Quick Laboratory, under Professor Nuttall, to whom I wish to express my thanks for the interest he has taken in my researches, and for his constant encouragement.

No drug has been found which will influence the fatal course of East Coast Fever or retard the multiplication of Theileria parva in the blood of the affected cattle.

The drugs which were tried with negative results were Trypanblue, Congo red, Tryposafrol, Creosote and Oleum copaivae, Arsacetin, Soamin, “606,” Emetine hydrochloride, Mercury salicylate, Mercury succinimide, Quinine bihydrochloride and hydrochloride, Ethylhydrocupreine, Ammonium fluoride, Potassium iodide, Sodium salicylate, Calcium lactate, and Nuclein.

All of our animals died—18 treated and 3 untreated—and showed typical lesions at autopsy. They were all infected by means of ticks (Rhipicephalus appendiculatus) which had fed on infected cattle as larvae and nymphs and been placed on the experimental animals as nymphs and adults respectively.

The increase in the number of parasitized red blood corpuscles, but for slight irregularities, proceeds continuously night and day until the animal dies. We have not as yet observed a case ending in recovery.

The accompanying table gives a summary relating to each experimental animal (except XII): the number and kind of ticks which produced infection, the incubation period, the time when the parasites appeared in the peripheral blood, the time when the animals died, and the maximum percentage of parasitized blood corpuscles observed during the course of the disease. The days are all reckoned from Day 1 when the infective ticks were placed upon the cattle.

The somatic muscle of Ascaris suum is principally under the excitatory control of neuromuscular junction transmitter, acetylcholine (ACh). However, it has recently been shown that neuropeptides also play an important role in the motor-nervous system and one of these, AF3 (AVPGVLRFamide), also contracts muscle. The events which trigger contraction to ACh and AF3 would appear to be different, with ACh activating a nicotinic acetylcholine receptor whilst the response to AF3 is most likely to involve a G-protein coupled receptor negatively coupled to adenylate cyclase. In order to further elucidate differences in the cellular signalling pathways through which ACh and AF3 elicit muscle contraction, we investigated the actions of protein kinase C inhibitors, tamoxifen and chelerythrine, on the dorsal somatic muscle strip of A. suum. Contractions in response to 1 μM AF3 were potentiated by 17% in the presence of 10 μM tamoxifen (P<0·05; n=8); however, contractions in response to 10 μM ACh were markedly inhibited (tamoxifen IC50 44±18 μM; n=6). Tamoxifen also blocked muscle cell depolarizations to 5 μM ACh (IC50 4±1 μM; n=6) and 1 μM levamisole (IC50 14±6 μM; n=4). This was unlikely to be a non-specific effect on the membrane as hyperpolarizations to 10 μM GABA were unaffected (93% of control with 10 μM tamoxifen; n=6; P>0·05). However, another inhibitor of mammalian protein kinase C, chelerythrine, did not affect the response either to ACh or AF3 (n=6).

The present study was performed on antigen-presenting cells (APCs) of Theileria annulata transformed dendritic cells (TaDCs) and monocyte-derived dendritic cells (MoDCs) to compare differences in antigen presentation and stimulation of T lymphocyte proliferation. Antigen presentation for T lymphocyte proliferation was analysed by flow cytometry. Additionally, the level of mRNA transcription of small GTPases of the Rab family expressed in the TaDC cell line was analysed by quantitative real-time polymerase chain reaction (Q-RT-PCR). The endocytosis rate of TaDCs was significantly (P < 0.01) lower than in MoDCs. In contrast, when T lymphocytes were co-cultured with TaDC-APCs T cell proliferation was similar, while co-culture with MoDC-APC stimulated proliferation of CD4+ cells to a greater degree than CD8+ cells. However, the efficacy of TaDC-APCs to stimulate T lymphocytes dropped as the number of passages of TaDC-APC increased. Likewise, the transcription level of Rab family genes also significantly (P > 0.001) declined with progressive passages (>50) of the TaDC cell line. We conclude that initially the TaDC cell line efficiently presents antigen to stimulate T lymphocyte proliferation to produce a cellular immune response against the presented antigen.

Psilochasmus oxyurus, type species of the genus Psilochasmus Lühe, 1909, has been redescribed from whole mounts and transverse, horizontal and sagittal sections. Twenty-five worms from one common mallard, Anas platyrhynchos L. and 12 from one greater scaup, Nyroca marila L. are considered as conspecific with P. oxyurus, although they show some variations in body size and shape of the testes. Of the other eight known species of Psilochasmus, five have already been synonymized and the remaining three, namely, P. indicus Gupta, 1957, P. alii Jaiswal, 1957, and P. megacetabulus Jaiswal, 1957, are declared synonyms of P. oxyurus.

We present a mathematical model which is used to interpret the dynamics of the immunological response of a mouse host to infection with the filarial worm Onchocerca lienalis. The model mimics changes in worm burden over time post-infection and after reinfection and its behaviour provides a good description of experimental results. Measured production of T-cells and eosinophils is also compared with the predictions of the model. Our results show that the immune response mechanism proposed on the basis of experimental results, involving CD4+ T-cells and eosinophil destruction of the parasite, is supported by the insights gained from the mathematical model. Also, using the parameters estimated to describe the primary infection dynamics, the degree of acquired immunity to secondary infection is also well described by the model. Our analysis highlights the importance of obtaining quantitative measures of the many rate parameters involved in even the simplest interpretations of immunological responses to parasitic infection.