1. Protein in wheat is the most important constituent, and therefore the chief constituent to breed for. No wheat variety possesses at once combined the desired characteristics of high protein, high yield, maximum flour production, and maximum bushel weight.

2. So far as climatic factors are concerned, a short, comparatively dry growing season, especially in the spring, in the case of winter wheat, favours the development of grain rich in gluten, and hence high in protein.

3. The most important ground factor in determining the starchprotein ratio is the water supply. The protein content has been found to vary from 11·63 per cent, under 22–24 inches of rainfall to 14·93 per cent, under 12–13 inches (Minnesota); and from 12·63 per cent, under 25 inches of irrigation to 13·62 per cent, under no irrigation (Utah).

1. A method is described by which it is possible to estimate the numbers of active protozoa in a soil.

2. The total number of protozoa is first found by a dilution method. A fresh portion of the soil is then treated with 2 per cent. HCl (sp. gr. 1·15) overnight. By this means all active forms are killed. A second count by the dilution method gives the number of cystic protozoa in the soil. From these results the number of active forms can be ascertained.

It is shown in the preceding pages that under certain cultural conditions the nodule organism from the roots of red clover, broad bean, lucerne and lupin exhibits a tendency towards granular disintegration of the cell with the formation of small non-motile coccoid bodies, about 0-4μ diameter.

In the cultures ordinarily in use these coccoid bodies are not formed extensively, but cultivation on soil extract media rapidly leads to their production, until finally they constitute the predominant type in the culture.

A Previous investigation by the writer (1) showed that cyanamide readily breaks down, yielding ammonia in normal clay and sandy soils. The evidence, however, threw no light upon the cause or nature of this change. This question was accordingly reserved for a later investigation. The concensus of the available evidence indicated that the production of ammonia from cyanamide in the soil is due to direct bacterial action. This view was held by Immendorff(2) and Kappen(3), who concluded that in poor soils of low bacterial activities cyanamide is not converted into ammonia but is chemically transformed into dicyanodiamide. Löhnis(4) at first accounted in a similar way for the formation of ammonia from cyanamide in the soil. He(5) assumed later, however, that cyanamide is normally decomposed by soil colloids into urea or possibly some other substances, and the latter are then converted into ammonia by the soil organisms. He adduced no direct evidence of the production of urea from cyanamide in the soil.

In a previous communication attention was called to the possibilities of partial sterilisation under field conditions in the case of the summer fallow of Egyptian agriculture.

This fallow period or “sheraqi” is particularly characteristic of the basin system of agriculture during the interval between the harvest of the winter crop and the Nile flood, but it is also common under perennial. conditions of irrigation after the winter crops.

Although during the last few years a good deal of work has been done on the soil protozoa, very little is known as yet as to their mode of life, behaviour and relations with the other soil organisms; so much is this the case that even the fact that they lead a trophic life in soil is often disputed. Since Russell and Hutchinson(16, 17) in their work on the partial sterilisation of soil first discussed the possible relations existing between the soil protozoa and bacteria, the question of the activity of protozoa in soil has become important. They found that partial sterilisation brought about an improvement in the soil as a medium for the growth of bacteria by the removal of a limiting factor, and further they showed that this limiting factor possessed many of the characteristics of a living organism.

1. The relationship between chemical constitution and toxicity to wireworms of organic compounds is found to be of a twofold nature.

2. The general effect of a group of compounds of the same type is directly determined by the chemical constitution of the type. The particular effects of individual members of the groups are limited by their physical properties such as volatility etc., which may be regarded as indirect consequences of their chemical constitution.

3. The aromatic hydrocarbons and halides are on the whole more toxic than the aliphatic hydrocarbons and halides. The groups that influence toxicity most when introduced singly into the benzene ring are in order of importance the methylamido (most effective), dimethylamido, hydroxy, nitro, amido, iodine, bromine, chlorine, methyl groups (least effective). But this order is modified in presence of another group; thus when there is a CH3 already present in the ring the order becomes chlorine (side chain), amido, hydroxy, chlorine (ring), methyl. Chlorine and hydroxy groups together give rise to highly poisonous substances considerably more effective than where present separately. The association of chlorine and nitro groups in chloropicrin gives rise to one of the most toxic substances tested. Methyl groups substituted in the amido group of aniline increase toxicity more than if substituted in the ring.