The importance of certain species of fleas in relation to the epidemiology of plague has been so amply demonstrated (see Journal of Hygiene, vols. vi. 1906, p. 426 and vii. 1907, p. 395) that an explanation appears scareely necessary for our publishing a paper dealing with a revision of the non-pectinated eyed Siphonaptera. With the demonstration that fleas are capable of transmitting plague, their study at once ceased to be the mere hobby of a small group of entomological specialists. An accurate knowledge of fleas, both with regard to their structure and biology, is at present a matter of prime importance to those who concern htemselves with the prophylaxis of plague.

Since November 1906 I have had in the animal house attached to the Bacteriological Laboratory, a rather large female Macacus pileatus (No. 47). This monkey, which had been bought from a villager, had never been used for any experiment: it was kept in the same cage with a monkey inoculated with yas. In October 1907 the monkey, which so for had been in good health, began to lose appetite, and looked somewhat ill: nevertheless the animal continued to jump about in the cage and play with its compantion till a short time before death, on 5. xi. 07. The monkey never had any diarrhoea, and I thought it might have died from a peculiar form of malaria, extremely common in Ceylon monkeys.

Our observations on a large number of recently dead or dying grouse impels us to believe that in many cases death is primarily caused by the presence of parasitic worms, either Cestodes or Nematodes in various parts of the alimentary canal.

A few years ago it was believed that there was only one form of trematode responsible for the pathological conditions included in the term Bilharziosis, namely a worm, known as Schistosoma haematobium, which has had numerous other synonyms, but as I am dealing with the subject purely from a South African point of view, I need merely mention that given it by Dr John Harley, namely Distoma capense.

The muscles of the head. In the preceding part of this paper (Journ. of hyg., 1907, p. 297) some account was given of the muscles of the pharynx and there remain to be considered the rest of the muscles of the head.

In pigs in Western Australia it is of frequent occurrence to find at the seat of castration large oval fibrous tumours from the size of an hen's egg to that of a tennis ball. These have a thick fibrous wall with a cavity in the centre, which is frequently small in relation to the size of the mass. The walls of this cavity are brownish-yellow and degenerated and the contents usually sero-pus of a similar colour, though at times a large quantity of ordinary whitish purulent matter is found. In films made from this brownish-yellow pus and stained with weak carbol-fuchsin or Leishman's stain, varying numbers of spirochaetes mixed with minute cocci and bacilli and larger, occasionally spore-bearing, organisms will be found. These spirochaetes vary in length from 6 μ or less to 12 μ; their thickness varies from the most delicate tenuity to that of a tubercle bacillus; the spirals may be three or four and perfectly regular or, on the other hand, quite irregular, and acute bendings even at a right angle may be seen. Further, some of the large apparently bacillary organisms may show slight undulations suggesting that they are large forms of this spirochaete. Sections of the tumour show a fibrous stroma, becoming more cellular towards the centre where it passes into necrosed tissue swarming with organisms, amongst which, sometimes in masses, spirochaetes may be found. Where the still living cells abut on the necrosed area, a varying number of eosinophile cells are revealed by Leishman's stain.

In stained preparations Piroplasma canis, P. bovis and P. pitheci may be distinguished from other intracorpuscular parasites by the presence of intracorpuscular pyriform bodies, usually occurring in pairs and less commonly in fours, eights and sixteens. These pyriform bodies show a dense mass of chromatin near the pointed end and a loose mass, often connected with the dense mass, situated towards the blunt end. In suitable preparations peculiar dividing forms, most typically repre-sented by trilobed forms or more or less pyriform bodies joined to a single smaller rounded or elongated mass of protoplasm, may be seen.

These specimens were preserved in alcohol and contained in three bottles a, b and c.

(a) contained 1 large and 47 small leeches “out of infested springs at Safed, Palestine.”

(b) contained a leech “extracted from pharynx of an Arab of Jerusalem.”

(c) contained a leech which had been removed, by means of laryngeal forceps, from the vocal cords of a young peasant in Jerusalem.

The observations relating to the treatment of canine piroplasmosis by means of drugs are usually very briefly recorded so that the precise conditions under which they were conducted cannot be ascertained.

1. Some cases of remarkable resistance to nagana infection are recorded.

2. Although such birds as pigeons are unable to harbour the trypanosoma brucei, the kestrel is able to do so.

3. Attention is drawn to certain changes which are brought about by the trypanosome infection and the need for more precise chemical investigation of these haematozoal diseases.

A popular belief prevails in Russia that the bug Acanthia lectularia plays a part in the spread of relapsing fever. Flügge (1891) however appears to have been the first scientific writer to suppose that vermin might spread the disease. This view was also held by Tictin (1897) who considered that man may become infected by (a) being bitten by bugs which had previously fed on blood containing Spirochaeta obermeieri, or (b) by his crushing such bugs and infecting himself with the spirochaetes through lesions in the skin induced by scratching. Tictin injected the gut-contents of infected bugs which had recently fed on a relapsing fever patient into monkeys and infected them. When the bugs were crushed 48 hours after feeding on infected blood their contents did not produce the disease in monkeys.

The importance of various species of ticks in relation to the propagation of protozoal diseases, is so generally recognised that it has appeared to us eminently desirable to make a detailed study of one of the common species. Such a study has seemed to us specially necessary for the reason that our knowledge of these parasites is very imperfect, in spite of the fact that they possess an economic interest of the first order. Some of the diseases which ticks transmit, notably those due to the haematozoal parasites belonging to the genus Piroplasma, are among the most devastating affections of domesticated animals in many parts of the world, the useful animals which suffer from piroplas-mosis being cattle, sheep, goats, horses, and dogs. The disease known as “Heart-water,” occurring in South Africa and affecting sheep, goats and cattle, is likewise tick-transmitted. A disease of the domesticated fowl, analogous to relapsing fever in man, likewise of economic importance and occurring in different parts of the world, has also been demonstrated to be transmitted from animal to animal through the agency of ticks. The fowl disease is due to a Spirochaeta which is conveyed by ticks; the same holds for human “tick fever” and a spirochaete infection in cattle occurring in parts of Africa. Recent investigation appears to have clearly established the fact that a tick conveys spotted or Rocky Mountain Fever to man. Moreover it has been claimed that a Nematode worm, the Filaria perstans, parasitic in man, undergoes its development in a tick which is capable of conveying the parasite from one human host to another. There can be no doubt but that ticks will be found, upon further investigation, to be associated in the transmission of an increasing number of diseases in animals.

The object of this paper is to describe the protozoan parasites which I have encountered in the red blood corpuscles of three different snakes —Boa constrictor, Python spilotes and Coluber quatuorlineatus. All the Protozoa are members of the genus Haemogregarina.

In a memoir recently published, Salvin-Moore and Breinl state that when Trypanosoma gambiense is examined in the blood “it does not seem possible to detect any true dimorphism or trimorphism.” “The three forms often described and alluded to as distinct, consequently appear to be arbitrarily chosen examples in a continuous series of dimensions.” It has always seemed to me very remarkable that the great differences in form and structure, no less than in size, between the slender, ordinary, and stumpy forms of T. gambiense, differences noted by all competent observers, should have been denied by two authors who claim for their methods of technique a superiority over those employed by all other investigators.

The first experiments upon the transmission of T. lewisi by fleas were carried out by Rabinowitsch and Kempner (1899) who observed that three fresh rats placed with others harbouring trypanosomes in their blood subsequently (after 11–15 days) became infected. Fleas (species?) were found on these rats. They next teazed the bodies of fleas taken from infected rats and inoculated them into fresh rats with the result that in five out of nine experiments the fresh rats became infected with T. lewisi. In one experiment they removed 20 fleas from infected rats and placed them on a clean animal with the result that the latter became infected after 2–3 weeks. They regarded this one experiment as conclusively proving that T. lewisi is transmitted by rat fleas.

In the year 1881, G. Haller published a description of the sensory organ of ticks which has since borne his name; he was apparently so much impressed by its remarkable similarity in structure to the auditory organs of many Crustacea, that he assumed it to be an organ of hearing, and even went so far as to describe the presence of otoliths within one of the cavities of the organ. Since that time, other zoologists appear to have given little attention to this structure, the majority of those who have had occasion to mention it, contenting themselves with a brief resumé of Haller's observations and a reference to his paper.