The Japanese observers Ido, Hoki, Ito and Wani (1916) state that in Infectious Jaundice the infective organism—the Spirochaeta icterohaemorrhagiae—is transmitted probably from rats to man by means of the urine of rats, directly or indirectly.

In the summer of 1916, during the advance across Sinai, the prevalence of amoebic dysentery amongst our troops occasioned the appointment of a Protozoologist to the Field Laboratories. While I was engaged in this capacity the work recorded in this paper was carried out.

1. Observations on E. histolytica from the human intestine have been made and compared with amoebae living in culture media and in the ulcers of the large intestines of cats, which have died of amoebic dysentery.

2. The effects of the substances chlorine, tyrosin, and skatol on culture amoebae have been investigated; it has been found that the two first substances stimulate vegetative reproduction, but that skatol induces cyst formation.

3. The changes that the nucleus undergoes preparatory to division and the behaviour of the karyosome during division are fully described. It is shown that the nuclei originally described as characteristic of E. histolytica and E. tetragena are phases of nuclear change in the life history of the same animal.

4. Cyst formation and the nuclear divisions in the cysts are described, together with a short discussion as to the view taken that the chromatoid bodies are not comparable with the chromidia of other Rhizopoda.

5. Reasons are adduced for the suggestion that during the further development of the cysts quadrinucleate amoebae emerge, which divide to form four small amoebulae.

6. Degeneration in E. histolylica is described and the view of Darling, that budding phenomena are degenerative ones, is confirmed.

Habitat and Record. Two specimens, ♀, were taken on Mustelus vulgaris ♂, the smooth hound, captured at Plymouth in August 1918. They were attached in the angle between the host's body and the pelvic fin and slightly to the left. [This location is unfortunate since the length of the attaching “arms” (2nd maxillae) I have endeavoured elsewhere to show, is a variable character not to be depended upon for the determination of species; for it is my experience that Lernaeopoda spp. have arms very short in this location.]

From a study of the organisms themselves, so far as this has been possible, and from an analysis of all accessible records relating to them, I conclude that there are four distinct species of coccidia which may parasitize man. These are: (1) Isospora hominis Rivolta, 1878 (emend.), discovered by Kjellberg in 1860. and recently investigated by Wenyon; (2) Eimeria wenyoni n.sp., a form discovered in 1915 by Wenyon; (3) Eimeria oxyspora n.sp., another new form, here described for the first time; (4) an undetermined species of Eimeria (?) which was discovered by Gubler in 1858. This last inhabits the human liver, whilst the three others probably live in the small intestine. Probably some seventy cases of infection with the Isospora have now been seen, mostly in persons who have been in the Near East; but the other parasites appear to be extremely rare, and little is known concerning their probable geographical distribution.

All these parasites are probably peculiar to man. There is no evidence that any of them is or can be parasitic in any other host. The prevailing belief that the coccidia of man are identical with those of rabbits, cats, or dogs, is therefore unfounded. Furthermore, there is as yet no good evidence to show that man may harbour any species of coccidia other than the four just enumerated. All these forms, however, require fuller investigation. They are here briefly and incompletely described from the data at present available.

There is at present no proof that the coccidia of man—with the probable exception of the species occurring in the liver—can produce a clinically recognizable pathological condition of “coccidiosis”: and as yet no method of treatment which will eradicate an infection with any species has been discovered.

Amblyomma dissimile Koch is well known to science and previous accounts of its biology have already appeared. Newstead (1909) made some observations on its habits in Jamaica. Hooker, Bishopp, and Wood (1912) give an exact account of its life cycle worked out in confinement in the Southern United States of America. These authors do not refer to the occurrence of parthenogenesis in this species.

Parasitology, XI, 120, five lines from the bottom of the page: For “first maxillae” read “second maxillae”.

Part I of this paper, which dealt exclusively with the females, appeared in Parasitology, VIII. 262. After examining some dozens of dogfish each month for the previous three years I, at length, on April 2nd 1918 obtained from two separate dogfish caught during the preceding week at Plymouth, three females of Lernaeopoda scyllicola which were accompanied by males.

The occurrence of cases of spirochaetal jaundice from time to time in our over-seas forces, and the general interest of spirochaetal affections at the present time, both in man and animals, are my excuse for offering the following notes.

The Hot Air Disinfestor herein described is the outcome of experiments undertaken in 1915, at the instigation of Colonel G. S. Rennie, C.M.G., then A.D.M.S., Canadians, Shorncliffe, in an effort to devise a satisfactory solution of the louse problem.

Habitat and Record. On 10. iv. 1918 my attention was called to five specimens of Lernaeopoda occurring on Scyllium canicula obtained at Plymouth. The largest copepod was attached outside and about one inch ventral to the left spiracle. The other four were deeply concealed within the left nasal groove, so that the nasal flap had to be cut away in order to detach the parasites. These specimens exhibit characters of their own which seem to combine those of other established species. The most striking modification is that the ends of the attaching “arms” (2nd maxillae) are expanded into large discs on either side of a vestigial bulla, thus recalling L. bidiscalis Kane, 1892, though that species is described as possessing discs of a different conformation, and as having no bulla. In other respects they agree more with L. musteli Thomson, 1899, notably as to their small size, and the proportion of the arms to their trunk. But to these points I do not attach much importance, since both may be due to the confined space in which the parasites are domiciled.

Refer to the conclusions stated at the end of the foregoing sections on pp. 204, 206, 217–219 and the foregoing paragraph.

The existence of trypanosomiasis amongst the ruminants of Turkestan has been suspected for many years, but the first definite record is that of Liihs (f906) who discovered Trypanosoma theileri in the blood of cattle in Transcaucasia. This was followed by the discovery of the same parasite in the Trans-Baikal Region (Dudukaloff), the Don Province (Stolnikoff) and in the Pskov and Vitebsk Governments (Yakimoff and Bekensky). Wrublewski found this trypanosome in the blood of bison from the Bieloviejsky forests and later it was discovered by Yakimoff in Turkestan.

For the purpose of testing culicifuges numbers of Stegomyia fasciata (the Yellow Fever mosquito), bred in incubators, were placed in cages kept in the laboratory. The efficiency of the preparations was tested by coating the forearm with a definite quantity of one or other of them and exposing in a cage, each test being controlled by inserting after a short interval the other and untreated arm in the same cage, the number of bites being compared in each case. By this procedure it was hoped to obtain a measure of the relative protection which the culicifuges might be expected to afford when used under practical conditions against Anopheles mosquitoes.

In the first series of trials conducted within 15 minutes of application, eight preparations out of a total of 22 tested gave satisfactory results. Their active ingredients were (1) Oil of Cassia and Camphor, (2 a) Oil of Cassia and Peppermint, (5) Oil of Eucalyptus and Citronella with Phenol, (9 a) Crude Naphthalene (coke oven) and Camphor, (10) Crude “Parasitox,” (15 a) Light Wood Oil, (21) Oil of Turpentine, (22 a) “Lawson's Anti-mosquito Compound.” These preparations were then tested to ascertain for what period their protection could be depended upon. Preliminary trials indicated that this period was not likely to extend for more than two hours between treatment of the arm and exposure in the cage. None of the preparations gave complete protection in this series of trials; the most efficient were Nos. 1, 21. 2 a, 15 a and 9 a, over a two hours period.

It appeared, however, that the two experimenters were unequally attractive to the mosquito. Making allowance for this, preparations 2 a. 1, 15 a, and 21 were almost on a parity, followed by 9 a, 10 and 5 in order. A series of experimental trials based on this element of preference on the part of the mosquito was confirmatory of the factor of preference and showed a ratio of attraction of about the order of G. T. 3, A. B. 2.

Observations on the behaviour of the mosquitoes during the tests suggest that the protection afforded does not result from a dislike of the insects to the culicifuge but to its obscuring the attractiveness of the human odour.

Regarding the make up of the essential ingredients it was found that fluid preparations were inconvenient and tended to be wasteful in application. Soap preparations, unless very soft, are apt to be difficult of economic use and in either case are more readily dissipated by perspiration than waxy or greasy ones. Culicifuges prepared with grease are more easily applied but are not so lasting as those put up with wax. Soft wax preparations, correctly adjusted to the temperature in which it is proposed to use them, are most suitable for out of doors use, especially in the case of troops. The retarding of volatilisation caused by the admixture of the active ingredients with wax or grease is a distinct advantage, but care must be exercised in respect of the relative proportion of active substance to the base. The golden rule is to use as much of the active constituent and as small a quantity of the inert base as is consistent with convenient application and the prolonging of the period of efficiency, not, as most proprietary compounders appear to think, as little as possible.

In choosing a culicifuge for use. the human factor of choice in regard to pleasing and unpleasing odours should be as little disregarded as consistent with efficiency. Where large quantities are needed cost is an important consideration, but must not be allowed to endanger the willing co-operation of the individuals it is desired to protect.

This paper is based on the study of a large material derived from various sources and containing a great number of abnormal specimens of Pediculus humanus, namely 155 hermaphrodites, besides abnormalities other than sexual which occur very rarely among insects.

The lice which infest man belong to the order Anoplura Leach 1817, containing two sub-orders, (i) Siphunculata Meinert 1891 and (ii) Mallophaga Nitzsch 1818. The family Pediculidae Leach is included in the Siphunculata1. Owing to the confusion which still persists in the literature regarding the nomenclature and systematic position of the two sub-orders of Anoplura, it appears expedient to review the evidence upon which the statement contained in the preceding paragraph is based.

The formation of a cocoon or of a more or less solid case by a larva before its transformation into a pupa, occurs very seldom in cyclorhaphous Diptera. This is due undoubtedly to the existence in all these Diptera of a puparium formed by the contracted and hardened last larval skin, in which, as in a cocoon, is contained and hardened last larval skin, in which, as in a cocoon, is contained the real pupa or chrysalis of the fly.

In the autumn of 1917 the writer received several letters from Mr L. C. Peters describing his experiences with flies hibernating in a large and very old house, situated in a large park at Frampton, near Kirton, Boston, Lincolnshire. Mr Peters' attention was directed first to the matter towards the end of October. On removing the window sashes the frames were found “black with flies.” After fumigation a bucketful of dead flies was removed from a single window frame, and about six bucketfuls from other infested windows. Only one side of the house was affected, but on that side the flies were found in the window frames on all three stories. “Ladybirds” were also present in large numbers.

In the following pages I shall endeavour to describe the present state of our knowledge of Bilharziasis in Natal and the result of some personal observations extending over the last seven years. The investigations of the Bilharzia Mission to Egypt have drawn attention to the various forms of cercariae which infest several species of fresh-water snail in African rivers. The cercariae which give rise to Bilharzia disease in Egypt are furcocercous cercariae, i.e. they possess a. tail which is divided for a greater or shorter portion of its length. They are characterised, further, by the absence of a pharynx at the commencement of the oesophagus. Similar cercariae are present in one of the species of fresh-water snail which abounds in the infected areas of Natal.

In the year 1915 the flies caught in traps baited with various materials and placed in different situations were recorded, and charts constructed showing the effects of various meteorological conditions on flies. “These charts showed that the curve for flies caught in traps corresponded most closely to the curve for the maximum temperature recorded by a thermometer exposed to the sun” (1916, 497 and Chart 5). During the years 1916 and 1917 traps baited daily with human excrement were exposed in sunny situations, and the flies caught in them recorded. Records of the hours of bright sunshine, of the rainfall, the velocity of the wind, the maximum temperatures indicated by thermometers exposed to the sun and in. the screen, the minimum temperatures in the screen and on the grass were kept. From these observations it was possible to compare the effects of meteorological conditions on flies in three consecutive seasons.