For the opportunity of studying this collection of round-worms from Zanzibar I am greatly indebted to Mr W. Mansfield-Aders, Economic Biologist to the Zanzibar Government.

The problem of sperm disinfection in mammals is not only interesting from the biological standpoint. It is of practical value especially in the horse-breeding industry.

In 1918 Southwell and Baini Prashad1 published a description of an unsegmented Cestode parasite—Ilisha parthenogenetica—which they discovered in the “mesentery” of the common edible Indian Shad, Hilsa ilisha. This minute parasite, according to these authors, “appears to be of very great systematic importance, and…further reproduces itself in a manner not before known amongst the Cestoda.” In justification of these general remarks, they make, among others, the following statements: (1) the parasite, though of the well-known Piestocystis larva type, becomes sexually mature and resides in a cyst formed from the tissues of the mesentery; (2) these cysts are so numerous in every individual fish examined that the mesentery becomes transformed into “a massive liver-like organ in which the various coils of the intestine appeared merely as tubes embedded therein”; (3) though two lateral main excretory canals are described, yet there is no terminal excretory aperture: the excretory system “is closed in all stages of [the parasite's] life-history”; (4) the whole of the parenchyma is “filled up with enormous numbers of minute egg-cells. Besides the eggs, morulae and other higher stages in the development of the young were also present in the intima.” In other words, the egg-cells “develop in the body of the parent to form young worms identical in structure and appearance with the parent”; (5) the young worms “escape through a temporary aperture which is formed in the middle of the rostellum, anteriorly,” and, when the old cyst has been ruptured, they become “scattered in the mesentery, the [new] cyst not having been secreted at this stage.”

In a recent contribution to Parasitology (present volume, p. 26) a short description of the male of this species was given. The type-material consisted of a single male from the Silurid fish, Heterobranchus anguillaris, from Cairo. Through the kindness of Dr W. N. F. Woodland, of the Wellcome Bureau of Scientific Research, the writer has recently had the opportunity of examining further material belonging evidently to the same species, the host being Synodontis eupterus and the locality Khartoum. This material consists of several males, one mature and two immature females, all mounted as microscopic preparations in glycerine-jelly. A few further details may now be added to the description of the species.

A short description is given of an important disease of sheep (Scrapie, Traber-krankheit, La Tremblante), believed to be caused by a heavy infection with Sarcocystis tenella, probably of increased virulence.

The itchiness and paresis, the congenital transmission by the mother, the non-contagiousness, the long incubation period, etc., are readily explained on this view and a method of control of the disease based on this theory has been highly successful.

The sarcocyst has been shown to be transmitted from sheep to sheep by intrauterine infection and by means of the milk.

The minute structure of the sarcocyst is described and it has been shown in particular that the sickle-shaped spores are surrounded by a capsule. Under certain conditions, as in 1 per cent, glucose water and in the centre of the ripe cyst, these spores swell out and become globular, eventually bursting and scattering small chromatin granules. The further evolution of these granules is dealt with.

The spread by means of milk and by the intestinal route is discussed1.

As a subject of investigation the Trematode fauna of British Birds does not appear to have aroused at any time much enthusiasm amongst British zoologists and as a result we owe the greater part of our knowledge of the subject to continental workers. The fact that our bird fauna is practically identical with that of the adjacent parts of Western Europe would lead us to expect that the parasites of our birds should not differ materially from those met with in the same species of birds on the continent. As a matter of fact, no species of bird Trematode hitherto recorded from this country can be regarded as peculiar to Britain, with the possible exception of Echinostephilla virgula Lebour, which, however, will almost certainly be met with in other localities later.

It is well known that the ectoparasitic Arthropods often produce in their host various skin reactions such as macules, wheals and haemorrhages, which in many cases are due to the salivary secretion of these ectoparasites. Nuttall and Strickland (1908) were the first to find an anticoagulin (called “Ixodin” by Sabbatani) in the salivary glands and alimentary canal of Argas persicus. Bruck (1919) found that the organs of Culex contained a haemolytic- and urticaria-producing substance called by him “Culicin.” His study was not, however, precise, because he ground up the entire bodies of the gnats, thereby mixing up secretions, excretions and fragments of organs, some of which would never enter a wound in the process of blood sucking. Moreover, the urticaria following mosquito bite was found by Schaudinn to be due to the yeast present in the oesophageal diverticula of mosquito. Klausner (1916) states that the secretions of the salivary glands in Cimex are soluble in water and alcohol, are haemolytic and produce urticaria; he found also that they do not contain formic acid and that immunity to their effects is not acquired. Nuttall (1918) dealing with the effects of salivary glands of Phthirus on human skin states that the bluish spots of the skin are especially marked after biting of adult lice, that they have nothing to do with the blue spots in the fat body of the lice and that they are probably derived from the exuded and altered blood of man.

Certain facts are known concerning the correlation of the distribution of animal species and the hydrogen ion concentration of the soil and water. An attempt is made to apply them to the distribution of malarial fever, as illustrating insect borne disease, and to some of the numerous Trematode infections, afflicting man and other animals, in which snails act as intermediate hosts. The importance of measurements of hydrogen ion concentration (by the colorimetric method) by field workers on the distribution of animals is urged.

The writer wishes to acknowledge his indebtedness to Dr M. V. Lebour for the suggestion that snails may prove a suitable group for the study of the relation between the reaction of the habitat and animal distribution.

Mr J. F. M. FLOYD was good enough to hand over to me for report some smears which he had made in British Guiana from the contents of Termite intestines. Prof. Silvestri, who was kind enough to examine some Termites taken from the same colony as those which furnished the material for the smears, identifies them as belonging to the species, Rhinotertnes nasutus Perthy, and it is probable that this is the host of the parasite described below.

During the year April 1921–April 1922 I examined the stools of 1034 men from the dysentery ward of the District Hospital, Kuala Lumpur, in the Federated Malay States. In this hospital the patients are for the most part indigent Chinese and Tamils of the coolie class, who have resided in Malaya for a length of time varying from a few weeks to a number of years, sometimes all their lives. From the way in which these people live, from the intimate mixture of so many different nationalities, and from their often extensive migrations, one might be led to expect that their intestinal fauna would be abundant both in variety of species and in incidence of infection. This expectation is not realised in the following results. Indeed, the figures for some of the non-pathogenic protozoa are not as high as some which have been obtained for healthy Englishmen who have never left England (cf. Matthews and Malins Smith, 1919). Nearly all the patients in this series were suffering, or had recently suffered, from active dysentery at the time when the examinations were made: and in some cases the flushing out of the intestine from this cause probably reduced the intestinal protozoa to such small numbers that none could be found when specimens of the stools were examined. In many cases, also, protozoa have certainly been overlooked in the masses of pus and other cells present in a very large proportion of the stools examined. Had it been possible to examine a series of cases without intestinal derangements involving diarrhoea from the same population, some opinion might have been formed as to the actual effect of these two factors on the results obtained. And until some such figures are available for comparison it cannot be said that the scarcity of some of the intestinal protozoa found in these cases has any special significance.

Geoffrey Watkins Smith, M.C., M.A. (OxoN.) was born 9 Dec. 1881 at Ivy Bank, Beckenham, Kent and was killed on the Somme, in July, 1916, at the early age of 34. He was Fellow and Tutor of New College and Lecturer in the Department of Zoology and Comparative Anatomy at Oxford. His published work covers a period of only eleven years but it is remarkable in quantity and quality alike and shows forth its author as one who would have achieved the foremost rank among English biologists.