1. The attack on the organic matter of different soils using varying strengths of hydrogen peroxide has been investigated.

2. Starting with the most dilute peroxide, a complex of constant composition is oxidised in increasing amount.

3. Above a certain strength of peroxide there is no further attack on the nitrogenous compounds of the organic matter, but a progressive decomposition of non-nitrogenous carbon compounds or complexes.

4. The fraction oxidised up to the point at which no further decomposition of nitrogenous matter occurs is termed the “oxidisable complex”, and, whilst apparently specific for a given soil, varies somewhat in composition in different soils.

1. An account has been given of the composition and weights of nutrients in 3200 wheat plants from seven weeks before ear emergence until the crop was harvested. The distribution of the plant nutrients, and the rate of assimilation and translocation of these nutrients, have been discussed.

2. In the case of the whole plant, the percentage of nutrients in the dry matter decreased from the time of the first sampling, with the exception of silica, which had a tendency to remain constant throughout. In the case of the ear, diminution in the percentage of nutrients in the dry matter was observed from a fortnight after ear emergence until harvest.

3. Marked increases in the weights of all nutrients in the whole plant were noted until ear emergence, from then onwards assimilation was much slower. The plant attained its maximum quantities of the nutrients in the following order: potash seven weeks, lime and chlorine five weeks, nitrogen three weeks, carbon, phosphoric acid and silica two weeks, before harvest.

Assimilation of these had, therefore, ceased at the above stated times, although transference to the ear proceeded until within about a week before harvest.

The following substances proved fungicidal for the conidial stage of the hop mildew (Sphaerotheca Humuli):

(1) Liquid paraffin at 2 per cent. emulsified with soft soap. The spray is harmless, or dangerous, to foliage according to the conditions (probably temperature) in the greenhouse.

(2) Medicinal paraffin, emulsified with 0·75 per cent. castor-oil soap, is not quite fungicidal at 3 per cent.

(3) “Summer solol”, a proprietary mineral-oil preparation containing 61·6 per cent. by weight high-boiling petroleum oils, is fungicidal at a concentration between 2·5 and 3 per cent. when 0·5 per cent. soft soap is added to confer satisfactory spreading properties. At this concentration no injury to the leaves was caused.

(4) “Volck”, a proprietary petroleum-oil preparation containing 80·0 per cent. by weight mineral oils, is fungicidal at 2·5 per cent. With either 0·5 per cent. soft soap or 0·5 per cent. Agral I. Injury may be caused under certain conditions.

Many authors have studied the post-natal growth of cattle (Ecles(7), Feldmann (8), Gärtner (10), Moulton, Trowbridge and Haigh (16, 17), Brody(4, 5), Fischer (9), Schmalhausen(19, 20) and many more).

On the other hand, embryonic growth has been studied only by a few (Hammond (11), Bergmann(1) and a few others), although Maligonoff (14, 15) pointed out the great importance of studying embryonic development.

Samples of milk from one hundred and forty-two mares have been analysed for the purpose of determining the percentage of solids, protein, fat, lactose and ash.

Of this number, thirty-eight samples were taken during the period of colostrum secretion and one hundred and four were colostrum-free milks.

The average composition of the milk of British mares has been found to be in close agreement with that of continental mares. The only marked difference is in the percentage of ash.

The average percentage of ash in the milk of continental mares is 0·38 and in the milk of British mares 0·51. It has been found that in the lighter British breeds (Ponies and Thoroughbreds) the ash content is similar to that of the continental mares, whereas in the heavier breeds (Clydesdales and Shires) the percentage of ash is appreciably greater.

1. At the completion of a 50-year cycle of continuous cropping with both wheat and barley on a light sandy soil at the Woburn Experimental Station, soil samples from all of the plots were analysed for replaceable bases.

2. The soil had little or no calcium carbonate originally and comparison with early soil samples showed that the unmanured plots lost about half of their replaceable calcium in the 50 years. The loss of calcium was much greater on plots with ammonium sulphate, and the crops failed completely in about 20 years. Plots with sodium nitrate or farmyard manure retained considerably more calcium than the unmanured plots.

3. Plots with mineral manures, essentially superphosphate and potassium sulphate, had less replaceable calcium in the earlier years but more in the surface soil at the end of the experiment than those without mineral manures. The effect of superphosphate was so slight that for practical purposes it may be regarded as without effect on the replaceable bases.

The results of a number of experiments carried out at Hillsborough on the growth of chickens, covering two seasons and involving 45 groups of 30 to 100 chickens, are discussed with particular reference to the variability of the live weights. It is concluded that the weights of cockerels or pullets taken separately should not show a standard deviation very much greater than 15 per cent. of the mean weight for the group, unless the experimental treatment or other conditions have seriously interfered with the rate of growth. It is pointed out that comparisons of mean weights and of standard deviations may be misleading unless cockerels and pullets are considered separately. Smallest significant differences between the mean weights of groups are tabulated for standard deviations of 15 per cent., 17·5 per cent, and 20 per cent., and for groups of 10 to 100 birds.

The writers do not mean to infer that the maintenance requirement of the adult sheep, as calculated by Wood and Capstick, is incorrect. The value obtained by these investigators is probably as reliable as any other which could be calculated from their data. The writers fully agree that Wood and Capstick's value is probably more accurate than previously estimated values of the maintenance requirement of the adult sheep.

1. Five typical British Guiana soil profiles, derived under humid tropical conditions from igneous rocks of different silica contents, are described, and the results of their detailed petrographical, chemical and ecological examination are presented and discussed.

2. Each kind of rock has produced a sandy, acidic, nutrient-deficient surface soil, but the katamorphic changes that have occurred during rock alteration, weathering and leaching have been fundamentally different.

3. The basic and intermediate igneous rocks have given rise within the zone of alteration to “primary gibbsitic laterite”, covering the parent rock in a thin crusty layer. Within the zone of secondary changes, the laterite has been resilicated, presumably through the agency of ground water containing soluble silica or alkali silicates (partially in the more basic rock profiles, and completely in the intermediate types), into kaolinitic earths, coloured yellow and red by hydrous iron oxides. Residuary gibbsite and iron oxides have accumulated in the more basic profiles as concretionary gravelly masses.

Recent work on the solubility of manganese compounds in the soil, leading to a general consensus of opinion that the solubility of this element is intimately controlled by the soil reaction and by the oxidation-reduction equilibrium, is shown to have an important bearing on the availability of this element to plants. This has been established by means of laboratory tests and pot experiments on three different soil types, characteristically deficient in available manganese. It has been shown that normal plant growth can be established on such soils either by increasing the acidity of the soil or by subjecting the soil to reducing conditions such as those brought about by high water saturation or temporary waterlogging. On these soils the increases in growth amounted to several hundred per cent. These responses are in every respect similar to those obtained by the application of manganese sulphate to the soils.

An account is given of three years’ observations on plots of permanent grass managed according to the “New System of Grassland Management”, which consists essentially of periodic dressings of nitrogenous manures followed by rotational grazing.

Results obtained by keeping records of the grazing provided and by sampling the plots show that the dominating factor on total yield has been rainfall. In the wet season 1930 the output of dry matter was about 80 per cent. more than in the dry year 1929: the extra grazing was about 46 per cent.

The increased grazing due to the nitrogenous manures (three dressings per annum each of 1 cwt. sulphate of ammonia per acre) has, on the average, been estimated at between 20 and 30 per cent. above the controls. This increase, however, has not been accurately measured.

In comparing the moisture contents of soils in the field, material precision is to be gained if the sticky points are also determined and the comparison based on the difference between the two values. There is a high degree of correlation between the moisture contents and sticky points of soils in moisture equilibrium with each other.

1. Organic sulphur determinations have been carried out on pasture grass at different stages of maturity. A decrease of about 39 per cent. was found in this constituent when the grass was cut for hay compared with the weekly and fortnightly stages of growth.

2. The application of heavy dressings of inorganic sulphates to a good heavy clay permanent pasture produced an average increase of 8 per cent. in the organic sulphur content.

3. No correlation was found between the organic sulphur and protein content of pasture grass, which suggests that the organic sulphur is present in part, at least, as non-protein sulphur.

1. A large number of observations on different soils in incubation, pot and field experiments have been made to determine the effect of the growing plant upon seasonal changes in soil acidity.

2. In every case it has been shown that the acidity of the uncropped soil increases to a maximum during the growing season and that the change may amount to more than one pH unit.

3. The plant reduces the change in acidity to a marked extent and at the height of growth there is a considerable difference between the acidity of the cropped and uncropped soil.

1. Eighty counts of soil bacteria and actinomycetes, made on mannite-asparagine agar and dextrose-casein agar, showed that the latter medium gave significantly higher numbers of bacteria in 76 per cent. of cases, and significantly higher numbers of actinomycetes in 60 per cent. of cases.

2. On mannite-asparagine agar the values of χ2 of the bacterial counts were as a whole in agreement with expectation. The counts of actinomycetes colonies on this medium showed a tendency to subnormal variation.