1. Infection with Dibothriocephalus latus for as long a period as nine months or with as many as three worms, apart from diarrhoea in the early stages does not necessarily give rise to any symptoms which would suggest the presence of the parasite.

2. In these experimental cases a definite train of symptoms, i.e., constipation for a period of one or more days followed by diarrhcua marked the onset of complete sexual maturity of the parasite.

3. No appreciable anaemia was produced, nor was there a definite diminution of erythrocytes.

Thanks to the kindness of Professor Leiper, opportunities were given to measure the red cells in these three cases of experimental Dibothriocephalus infection, and to construct Price Jones curves to show the distribution of the cells. In addition, Dr. J. Smith kindly supplied blood films and the particulars of a case of natural infection occurring in an Esthonian sailor, C. E., who was under his care in the City Hospital, Aberdeen, and which had been diagnosed by Prof. Leiper.

It is commonly asserted in the text books that the anaemia which occurs in cases of infection with this worm is identical with that found in pernicious anæmia. It seemed worth while, therefore, to see if there occurred the increase in the average mean diameter of the red cell, and the same cell distribution curve, which are to be found in pernicious anaemia (1922)

Towards the end of 1923 the results of some feeding experiments of mice with gravid segments of Hymenolepis fraterna Stiles and Hymenolepis longior Baylis were described (Jl. Helminthology, Vol. 1, pp. 195–196). Intravillous cysticercoids were seen in animals killed on the fourth day after feeding and ova were passed by infected mice after an interval of 19 days.

The suggestion having been put forward that this did not prove direct development and that the results could be explained by the mice shedding their villi containing cysticercoids, contaminating their food and re-ingesting them, further experiments were undertaken in order to note the progress of development from day to day, and also to find out whether ingested cysticercoids survive and produce adult cestodes.

Intestinal infections with parasitic worms are wide-spread in the Tropics. It is estimated that half the population of the World is infected with hookworms. Infection is propagated by contamination of the soil with the bowel discharges which contain the eggs of these parasites and prevention depends upon the adoption of a system of sewage carriage which ensures the safe disposal of the distribution of these eggs. The various methods of sewage disposal now operating in British Guiana and elsewhere in the tropics are adaptations, with few or no alterations, of schemes originally introduced to meet conditions prevailing in temperate climates. Prior to the visit of the Filariasis Commission of the London School of Tropical Medicine to British Guiana in 1921 the fate of the eggs of the hookworm and of other parasites in the system has not been scientifically studied.

Hassall and Stiles (1892) described this delicate parasite and gave it the name Strongylus rubidus. Our knowledge of it has recently been increased by Hall (1921) who has shown that it is not a member of the genus Strongylus, as represented by S. equinus of the horse, but is a member of the family Trichostrongylidæ. He has created a new genus Hyostrongylus for its reception and has devoted a large part of his paper to the consideration of a male accessory organ which serves as a guide for the spicules and to which he gives the name telamon.

In “Veterinary Medicine” for March, 1924, Dr. M. C. Hall contributes the third instalment of his paper, “Developments in Veterinary Parasitology during the past Fifteen Years,” and on pages 190 and 191, under the heading Lungworms (Metastrongylidæ), considers work on the life histories of the lung-worms of sheep and cattle, Dictyocaulus filaria and D. viviparus, and then refers to the paper under review. His words are as follows: “The life-histories of the swine lung-worms Metastrongylus elongatus and M. brevivaginatus have been ascertained by an American worker, Zebrowski. In general it is similar to that of Dictyocaulus filaria above, but the moisture requirements of the larvæ in cultures are rather exact. Zebrowski's work, published in 1921 in the proceedings of the Indiana Academy of Science, has been quite generally overlooked.”