A micro-pipette for the ultra-mechanical analysis of soils is described. The sources of error in the usual centrifugal methods are discussed and the new method is shown to be simple, accurate and capable of being adopted as a routine method even in the most moderately equipped laboratories. The treatment of the soil with alkaline permanganate to destroy humus does not affect the inorganic soil colloids.

1. Biological trials have been carried out to determine the efficacy of petroleum ether as solvent for the extraction of pyrethrum flowers for analysis. 95% of the toxic material was extracted from flowers one year old after only 3 hr. percolation. An extraction period of 8 hr. with petroleum ether is suggested.

2. A method of preparing colourless extracts of pyrethrum and analytical data for such extracts are given. They are shown to be of value for the preparation of concentrates of the pyrethrins. The preparation of a colourless concentrate containing 93% of total pyrethrins, as determined by a modified Seil method, is described.

1. Blood copper data are reported on ninety-four sheep divided into four experimental groups on a “border-pining” hill-side in Northumberland in 1940, in comparison with more extensive findings reported in 1939.

2. The mean value for comparable sheep was 0·080 mg. % in 1940 as compared with 0·086 mg. % in 1939, the overall range, 0·013–0·210 mg.%, being even wider than before.

3. Variations between animals comprising a group were as wide as between groups, and blood levels were not affected by moderate variations in Cu intake. Only in young sheep was there any evidence that a mineralized cake supplement, containing copper sufficient to double the natural grazing intake, had any elevating effect on blood copper.

4. Variations between values for the same individuals in 1939 and in 1940 were as wide as between different individuals in either year. Over 25% of the sheep showed Cu levels in 1940 falling within ±0·01 mg. % of their 1939 values, but nearly 20% showed figures differing by more than ± 0·05 mg. %, irrespective of differences in group treatments.

5. The significance of the figures, for normal. Northumbrian ewes is discussed in relation to those reported for Derbyshire ewes bearing lambs affected with “enzootic ataxia” or “swayback”.

1. Experiments have been carried out to determine the relation between the moisture content of artificially dried grass and the relative humidity of the surrounding atmosphere. This relation is given by a smooth curve. At relative humidities which are typical of outdoor winter conditions in the British Isles (80–90%) the equilibrium moisture content lies between 18 and 30%.

2. The rate of moulding is directly related to the relative humidity and therefore to the moisture content of the dried grass. For reasonably safe storage a relative humidity of 67 % should not be exceeded. This corresponds to a moisture content of roughly 13 %. Even this low value does not confer absolute immunity from mould growth.

3. The importance of extending storage trials over long periods is stressed. In one instance storage for 300 days was required before mould growth occurred. Neglect of this fact may account for the widely held view that a relative humidity of 70–75 % provides safe storage conditions.

4. Attempts to detect mould growth at an early stage by plating methods proved unsuccessful. It is shown that the two earliest and most reliable indications of mould growth are (i) the appearance of visible mycelium when the product is examined under a low-power objective, and (ii) the detection of a musty smell.

The experiments conducted at Ottershaw Park in the years 1937, 1938 and 1939 indicate that for a well-drained sandy loam, under a considerable range of moisture-supply conditions, main-crop potatoes do not respond in the absence of weeds to ridging-up, or to deep or frequent inter-row grubbings, by any increase in yield or in the percentage of ware. The crop showed successful powers of adaptation to a range of contrasting inter-row tillage treatments.

The potato crop showed considerable sensitivity to weed competition in the early stages of growth. This indicates that it is of great importance to maintain the crop in a weed-free condition during this early period.

Inter-row tillage operations on this type of soil should, therefore, be designed to destroy weeds and to provide moderate cover for the tubers. Intensification of such tillage beyond these limits is not of direct benefit to the plants.

No moisture-conservation effect of any importance was produced by a 3 in. soil mulch during dry weather, even when the water-table lay within 4 ft. from the surface.

A significant upward movement of water from the water-table to the surface soil was observed, but this was limited to a vertical distance of approximately 4 ft. for the soil type described. Beyond this limit the surface soil was apparently unaffected by the depth of the water-table.

These results may not be applicable to heavier soil types. It is probable, however, that they would hold good for most sandy loams.

The results indicate the desirability of carrying out further experiments on contrasting British soil types, especially in the important potato-growing areas.

It has been shown that a diet supplying, in addition to barley meal, weatings and 2% of lucerne meal, 5% of fish meal up to 90 lb. live weight, 2% from 90 to 150 lb. and no protein-rich food from 150 lb. to slaughter at about 200 lb. live weight, will give almost as good results, from the standpoints of mean daily live-weight increase and efficiency of food conversion over the whole period as one that provides 10% of fish meal from weaning to 150 lb. and 5% of a protein-rich food such as ex. soya bean meal from 150 to 200 lb. live weight. The small differences noted in the present trial were not statistically significant. It is true that the reduction of the fish meal supply to 5% or less retards to a significant extent the rate of growth up to 90 lb. live weight, but this initial setback, according to the results of this and the writers' previous investigations, tends to be wiped out during the later stages of feeding.

Further, a diet supplying, in addition to cereal, weatings and a small proportion of lucerne meal, as little as 2% of fish meal up to 90 lb. live weight and no protein-rich food at all thereafter has been shown to give results that are not seriously inferior, particularly when viewed against the background of wartime conditions, to those obtained on the standard diet. In this treatment, the protein required for growth beyond 90 lb. live weight was supplied by a diet of barley meal and weatings reinforced by 2% of lucerne meal.

1. A study of the length of the rachilla in barley shows that it is a varietal character, although strongly affected by environmental factors.

2. Rachilla length as a varietal character is affected by the density of the ear and the type of hairs or bristles borne on the rachilla.

3. In six-row barleys the length of the rachilla of the lateral spikelet is greater than that of the corresponding median spikelet.

4. In the absence of any of the complicating factors mentioned above, rachilla length is inherited as a straightforward quantitative character with an intermediate F1 and no signs of segregation in the F2. The number of major factors when the extremes of length are hybridized appears to be in the neighbourhood of four.

5. Hybridization of “Archer” and “Chevallier” type parents has given “dominance” of length and a possible heterotic effect. Long rachilla in these crosses appears to be linked with the “Chevallier” rachilla type.