1. The possibility of correlating the acidity of the soil with the distribution of cysts of Heterodera schachtii is investigated by a colorimetric method of hydrogen ion determination. The variety of this eelworm which infests potatoes is alone considered, the material being derived from South Lincolnshire—in particular from Kirton and the district around Boston. The samples, general notes and cyst-concentration data are due to Morgan, to whom the writer is greatly indebted.

2. A brief account of the life-history of H. schachtii is given, and also:

3. A note on the theoretical aspect of hydrogen ions and of the colorimetric methods for determining their concentrations.

4. The technique involved is fully discussed, and after various tests is standardized as follows : 2 grams of dry, finely-sieved soil are shaken up with 10 c.c. of twice-distilled water for ¼ hour. The mixture is centrifuged for 5 minutes and diluted with water in the ratio 1:9. A suitable indicator is added, aeration of the solution follows, and the pH-value is read by comparison with indicator-standards in a Walpole Comparator.

It is pointed out that at most the results give the pH-value of the solutions. The pH-value of the soil itself, in situ, is not determined, so that the results are only of relational value.

The Cairo City Police is a force consisting of more than 5,300 men. They are recruited principally from the Egyptian Army Reserve or by direct conscription. They are mostly derived from the poorest classes of the agricultural population and the artisans of the towns. Any individual can be exempted from enlistment in the Army on paying £E.20, and it is only those who cannot afford to pay that sum that are enlisted if medically fit.

During the winter of 1921–22 I visited the slaughterhouse at Aberystwyth at least once each week for the purpose of studying the helminthic parasites of sheep and pigs in the neighbourhood. An average of 50 sheep and 8 pigs were examined weekly from November 26th, 1921, to April 28th, 1922. Metastrongylus elongatus and M. brevivaginatus were present in the bronchioles of 50 per cent. of the pigs examined, generally both species being present in the same animal, and I took the opportunity of working out the anatomy of these two forms in detail, and indicating the differences between them; but before being able to publish my results Gedoelst covered the ground in his “Le Genre Metastrongylus Molin, 1861,” published in 1923.

During the winter of 1925–1926 the writer had the opportunity of staying on a farm in the Northern districts of Natal, South Africa. This farm—about 1,000 acres in extent and situated some 4,000 feet above sea level—is used primarily for sheep grazing, although cattle, horses and goats also form part of the farm stock. Half of the farm consists of a mountain rising to just above 5,000 feet above sea level, and the rest of the farm consists of an undulating plain. Except for a few depressions towards the foot of the mountain, which, during the rainy season become somewhat swampy, the whole farm may be considered as being very well drained. In consequence it is entirely covered with grass, there being no evidence of bush formation. Three rivulets, giving an abundant water supply, take their origin from the mountain.