The history of the ticks (Rhipicephalus appendiculatus) employed for transmission of East Coast fever is detailed in Part I. During the 1st day the ticks generally become attached and are partly held in place by a kind of cement substance (Fig. 1).

Penetration usually occurs at some time during the 2nd day, and the cellular elements of the corium quickly respond. There is a local swelling of the capillary endothelium, an infiltration with polymorphonuclear leucocytes and a slight increase in eosinophiles. More cement substance is produced which hardens about the edges. Some of it enters through the wound and spreads out in the corium along lines of least resistance (Fig. 2).

Later on the eosinophiles increase greatly in number and in turn give place to macrophages which ingest some of the cement substance. Mast cells also become more numerous. The area of reaction extends 2 or 3 mm. from the tip of the proboscis. Marked cytolysis of fibroblasts, of histiocytes and of the swollen endothelial cells occurs. The latter leads to haemorrhage (Figs. 6, 8, 9). The red blood cells and leucocytes are, however, not destroyed. They are sucked up by the tick, the leucocytes first because they accumulate before the haemorrhages take place.

Twenty-five of the sixty-six ticks examined were found to contain parasites in their salivary glands, but no parasites were seen in the sixty-six pieces of skin excised while the ticks were attached. Soon after the parasites enter the blood stream and spread throughout the system the corium of the skin is invaded by them like other parts of the body (Table III).

The medium-sized lymphocytes are the principal cells parasitised; but parasites are also found in lymphoblasts, large and small lymphocytes and occasionally in parenchymatous liver cells. We never saw them in vascular endotheial cells. For this reason we are unable to substantiate the view, which has apparently never been seriously questioned, that they undergo schizogony in this situation. The first agamonts were noted in lymphocytes in gland smears the day the fever first exceeded 103° F. The gamonts appeared about a day later and the intra-erythrocytic forms soon after. Taking the average of a number of cases: (1) The temperature first surpassed 103° F. on the 9·8th day after infestation with ticks. (2) The first Koch bodies within lymphocytes were observed on the 14·8th day, that is to say, 5 days after the fever commenced. (3) The first parasites within the red cells were noted 1·6 days later, on the 16·4th day after infestation.

The cycle which the parasite undergoes in changing from the agamonts to the intra-erythrocytic forms is illustrated in Diagram II (fully described on p. 36).

The alterations in the tissues caused directly or indirectly by the parasitic invasion were studied principally in specimens secured at autopsy from animals killed in extremis. The changes which apparently dominate relate to the lymphatic system. The medium-sized lymphocytes and to a less extent the small and large lymphocytes and lymphoblasts, first in the lymph glands and later in all parts of the body, become infested with Koch bodies which grow in their interior apparently without causing any severe injury. The distribu tion of Koch bodies is recorded in Table III, and their incidence in the lymph glands and in the liver in Tables IV and V. The evidence presented does not support the current conception that the parasites serve as a powerful stimulus to the multiplication of lymphocytes. The enlargement of lymph glands is caused more by oedema than by increase in their number. But there is a marked redistribution of lymphocytes. Their number is reduced in the lymph glands and in the peripheral blood stream and increased in the blood vessels of the liver and some other organs. Perivascular lymphocytic infiltrations are also a notable feature of the reaction in the liver, kidneys, adrenals and several other organs, but they are of rare occurrence in the nervous system. It is uncertain how far they are formed by the emigration of lymphocytes from the blood stream and by the proliferation of lymphocytes previously present perivascularly.

Small haemorrhages constitute a second alteration of importance. They are particularly prone to occur in the epicardium and endocardium, but may be found in almost any part of the body. Evidence is lacking that these haemorrhages play a part in the genesis of the perivasoular lymphocytic infiltrations. The latter are far more widespread and are chiefly observed in locations where haemorrhages are seldom seen.

Oedema is a third type of reaction. It is constantly found in the lymph glands and occasionally in the lungs, especially in the later stages of the disease.

Generally speaking, therefore, the lesions reported in this paper are acute in type. The functional activity of the several organs (except the lymph glands) has not been impaired sufficiently severely or over a time long enough to leave distinct structural changes in the parenchymatous organs; but the specimens examined were not collected from protracted cases of East Coast fever or from animals under suspicion of having undergone repeated attacks of the disease.

It is the parasites in the red blood cells which are capable of continuing the cycle if they are ingested by ticks able to act as vectors. We have recog nised three principal groups: (1) small spherical-ovoid parasites which are the first to make their appearance, (2) tailed parasites, and (3) plunip forms, both of which develop later and become more numerous than the spherical-ovoid parasites. Possible stages of transition are represented in Diagram I (p. 37). Though many parasites undergo differentiation and some probably divide, a variable number degenerate within the erythrocytes.

We question the validity of the genera into which the family Theileriidae are customarily divided on account of the inadequacy of the data on which they are based.

1. The results of further tests with the red-cell adhesion phenomenon in trypanosomiasis of man and other animals, described first by Duke and Wallace (1930) and later by Wallace and Wormall (1931), are discussed.

2. The conclusion is reached that the tests should always be made with several different strains of trypanosomes; in this way the number of negative results with undoubted cases of trypanosomiasis is decreased considerably. It is also advisable to have available stock adhesin sera (human or monkey) so that preliminary tests can be made to determine whether the trypanosomes in any animal are capable of giving adhesion. In doubtful cases of trypanosomiasis, treatment with trypanocidal drugs should be started. This treatment usually results in a marked improvement in the power of the serum or plasma of men and monkeys infected with trypanosomes to give red-cell adhesion.

3. If a suitable small amount of phenol is added to the serum of a trypanosomiasis patient, this serum can be kept at the ordinary temperatures for 3 weeks or more without appreciable loss of its power to give red-cell adhesion. In this way it is possible to carry out tests at a central laboratory on sera which have been collected at outlying stations.

4. Experiments have been carried out to determine the amounts of adhesin and complement (or “X factor”) required for red-cell adhesion.

5. The adhesin is non-dialysable, and in this, and many other respects it behaves like a true immune body.

The prophylaxis of plasmodial infections, by means of drugs in general, and by plasmoquine in particular, has been the subject of two reports to which we wish to refer: (1) by James, Nicol and Shute (1931), and (2) by Swellengrebel and de Buck (1931). The authors of report (1) obtained complete success by the use of 0·06 g. of plasmoquine before, and daily for 6 days after, the bite of infected mosquitoes, while the authors of report (2), giving 0·03 g. of the drug daily, had but poor success, notwithstanding Ottolenghi and Brotzu (1929), whom they cite, having reported that 0·02 g. daily with 0·25 g. of quinine was a good practical prophylactic.

In 1922 J. W. W. Stephens the morphological characters of the asexual forms of a malaria parasite which he had studied in the blood of a patient from East Africa were different from those of any usually accepted species, and he proposed to establish the parasite as a new species with the name Plasmodium ovale. In 1927, in collaboration with D. U. Owen, he confirmed and extended the description from the study of a case infected in Nigeria. In 1930 Warrington Yorke and D. U. Owen studied another case from Nigeria and, by utilising this patient's blood in the practice of malariatherapy, they were able to show that the peculiar morphological features of the asexual stages of the parasite remain constant when it is passed from person to person by direct blood inoculation.

The experiments described show that plasmoquine is very effective in preventing or delaying attacks of malaria in birds infected with P. relictum by direct blood inoculation, but has little or no prophylactic action in birds infected by the bites of mosquitoes.

In the mosquito-induced malaria parasites may appear in the blood 3 or 4 days after the cessation of plasmoquine treatment and there is no appreciable delay as compared with untreated control birds.

In continuation of our investigations on the relationship between the various Coccidia living in man and carnivorous animals (dog, cat, fox, etc.), we have had the opportunity of examining the intestines of several badgers, Meles taxus, which died in the Zoological Gardens, Budapest. These examinations revealed in a number of cases the occurrence of Coccidia belonging to both Eimeridae and Diplosporidae. In order to eliminate the possibility of these coccidial infections having been derived from other animals (fox, dog, cat), kept in close proximity with the badgers, it was found necessary to determine whether such infections also occur in badgers living under natural conditions. With the kind help of Prof. Raitsits, head of the ambulatory clinics of our College, we succeeded in obtaining a young specimen of Meles taxus, which not only harboured Coccidia, but subsequently served as an experimental animal for various cross-infections.

On 28. viii. 1932 seven specimens of Graffilla gemelipara Linton 1910 were found by Miriam Rothschild on the body inside the mantle cavity of a specimen of Cardium edule from Millbrook, Plymouth.

Though only taken previously in America and on a different host, Modiolus plicatulus, Linton's excellent figure leaves no doubt that these specimens belong to the same species.

The priority of the names of the fishes in the following list has been determined from Jordan in Part II of the Report of the United States Commissioner of Fisheries for the year 1928: A check list of Fishes. In determining the names of those not mentioned in this list I have to thank Mr J. R. Norman of the British Museum for his kind assistance.

The following constitutes a supplement to my previous list (Leigh-Sharpe, 1926), and consists of a few records previously omitted, and also an account of some Copepoda taken by me during a visit to the Laboratory of the Marine Biological Association, Plymouth, Aug.–Sept. 1932.

In The Entomologist of August, 1928, P. G. Shute gave an account of mosquitoes reared from larvae collected by him in salt marshes at Walton-on-the-Naze (Essex), which, he stated, though closely resembling Theobaldia (Culicella) morsitans Theo., differed from that species in certain respects, notably by having the male adult palps distinctly shorter. The description given by Shute of this “short-palped” Culicella was as follows:

Larvae. Dark brown in colour, pecten teeth more widely spaced in typical C. morsitans and sometimes extending as far as one-third the length of the siphon. Comb scales taper sharply at the base. Anal gills shorter, hardly more than one-third the length of the anal segment.

The new species herein described, collected by Mr Charles Elton in the course of ecological field work in Norway, was very kindly passed on by him to me for identification and description.

The examination of a water moccasin, Agkistrodon piscivorus, caught near Houston, Texas, on May 4th, 1932, revealed five species of parasites, four of which have not been previously reported from this host.