The addition of aluminium salts to culture solutions and to soils will bring about certain changes; these may be summed up as follows:

1. A change in the hydrogen ion concentration, which will vary in amount with the original buffer properties of the solution or the soil.

2. A change in the buffer properties of the solution or the soil; the hydrogen in concentration of a culture solution containing an aluminium salt will tend to remain more constant than that of a normal culture solution during the period of growth of the plant, when both start at the same pH value.

3. Precipitation of soluble phosphate as aluminium phosphate except in solutions or soils more acid than pH 3·5 to 4·0; this might lead to phosphate starvation in water cultures but would have little or no effect in a soil, where the particles would remain accessible to the plant roots.

Data from 26 flocks, involving a total of 5014 pure-bred Southdown ewes, were available for analysis and discussion. For ewes of all ages the proportion giving birth to twins is closely associated with the total yield of lambs, and while barrenness and abortion may to a certain extent be due to the same causes, it is those factors which cause abortion which also affect the yield by reducing the number of single births, rather than the number of multiple births.

The low fertility of shearling ewes is due to barrenness through reduced or delayed ovulation.

The writer wishes to express his thanks to the breeders who supplied the records of their flocks and particularly to the Honorary Secretary of the Southdown Sheep Society for his help in the collection of these records.

In the Journal of Agricultural Science for October 1921, Dr J. W. Capstick described a calorimeter large enough to take a full-grown pig or a small bullock. This apparatus was in regular use up to the end of 1923 and proved, on the whole, quite satisfactory.

1. A measure of the errors involved in the weighing of dairy cows for experimental work is presented.

2. Methods of avoiding a considerable part of these errors are suggested.

The figures analysed in the subsequent pages were obtained (by the kind permission and help of Prof. S. Pennington) during the five years, May 1920 to May 1925, from the College Farm dairy cows at University College, Reading, and before proceeding, a few notes on the herd and its management are desirable.

The herd is small (14–18 animals), and was established in 1908 by purchasing non-pedigree Dairy Shorthorn heifers which have since been “graded up” by the use of Pedigree Dairy Shorthorn bulls. The cows are typical Dairy Shorthorns, of a fairly large size, and the degree of fatness normally maintained might be described as good thriving condition, and probably better condition than average dairy cows.

The question of the composition of sugar beet tops and their utilisation for feeding purposes has been dealt with in a recent publication (l). The purpose of the present communication is to record the results of investigations into the problem of the preservation of sugar beet tops by the method of ensilage. The account falls naturally under four headings:

I. Ensilage of sugar beet tops alone.

II. Ensilage of sugar beet tops mixed with wheat chaff.

III. Ensilage of sugar beet tops mixed with wet sugar beet pulp.

IV. Nutritive value, as determined by digestion trials on sheep, of the silage obtained from the mixture of tops and pulp.

The investigations described in the present paper are based on the records of the dairy herd at the farm of the University College of North Wales, at Aber near Bangor. The results obtained will have a more definite significance if some account is given of the nature and management of that herd.

The Bangor provincial area, including the four Northern Counties of Wales, is roughly divided into Welsh Black and Shorthorn country by the Conway River. Most of the cattle in Anglesey and Caernarvonshire are of Welsh Black type, and the ordinary non-pedigree dual purpose type of Shorthorn predominates in Denbighshire and Flintshire.

The facts and considerations set out above provide the information necessary to enable an intelligent pig-keeper to compute on a logical and scientific basis a series of rations which from the energy point of view will produce any desired rate of live weight increase within the capacity of his animals. It is however necessary to make the reservation that the data apply strictly only to pigs of the Large White breed kept under good conditions and liberally fed.

It should also be noted that the method can only be applied to animals of known age and weight.

The method is applied as follows:

1. From the age of the animals read off from the basal metabolism chart, Fig. 1, the intensity of the basal metabolism per square metre per hour.

2. From the live weight—surface chart, Fig. 2—read off the surface area in square metres corresponding to the animal's live weight.

3. Multiply the basal metabolism per square metre per hour by the area of the animal's surface in square metres. The product multiplied by 24 gives the basal metabolism of the animal per day.

4. To get the practical maintenance requirement add to the basal metabolism per day 1000 calories to allow for an average amount of muscular effort.

5. Decide the growth rate in pounds of live weight increase per day at which it is desired to aim. The growth rate curve, Fig. 4, will help in assessing this figure.

6. Read off from Fig. 3 the calorie value per lb. of live weight increase corresponding to the live weight of the animals under consideration, and multiply the figure there found by the desired live weight increase in lb. per day. This will give the productive ration in calories per day.

7. The total ration is then found by adding together the maintenance requirement estimated in 4 above and the productive ration estimated in 6 above. This gives the total ration in calories of net energy.

8. Transform calories of net energy into lb. of meal on the assumption that 1 lb. of meal supplies to the pig 1000 calories, or preferably that 1 lb. of starch equivalent supplies 1500 calories.

It is of great importance that milk should possess a pleasant flavour, but in spite of much trouble which is devoted by farmers and dairymen to this aspect of dairying, it happens from time to time that mishaps do occur. Taints and flavours in milk are due chiefly to the following three causes:

1. The activity of contaminating micro-organisms.

2. The action of milk on metals.

3. The influence of the foods eaten on the milk produced.

It must be admitted that we have very little knowledge of the subject of milk flavours and taints, and there seems little doubt but that the blame for many taints caused by micro-organisms has been associated wrongly with foods and sometimes with manures.

(1) A review of the literature on the digestibility of wheat by poultry revealed the fact that, whereas there appeared to be but little variation in the digestibility coefficients for organic matter and N-free extract, considerable variation existed in the digestibility coefficients for crude protein, fibre and ether extract. It was considered desirable, therefore, to carry out digestibility determinations of known varieties of English wheats in order to ascertain how far such variations could be attributed to different varieties of wheat having been used in these experiments.

(2) Experiments carried out with Little Joss wheat and Yeoman II wheat gave closely concordant results for all nutrients other than ether extract.

(3) The results obtained in these experiments support the view that the digestibility of crude fibre by poultry is negligible.

(4) Except in the case of crude fibre and ether extract, poultry appear to be able to digest wheat as efficiently as other farm animals. Poultry are, however, distinctly inferior to other farm animals in their capacity to digest crude fibre and ether extract.

(5) The results of the present experiment show general agreement with previous work, except in the case of protein, where the digestibility coefficients are distinctly higher than those hitherto recorded. The explanation of this result may possibly be sought for in the improved methods used in the estimation of uric acid and ammonia

A physical form of “ropiness” in milk has been described and shown to be due to the formation of thin films of casein and (or) lactalbumin at the milk-air interface.

The “ropes” are a form of the “mechanical surface aggregates” of Ramsden and may occur on appropriate surfaces, such as ordinary farm coolers whenever the rate of flow, the temperature and the acidity conditions are favourable.

A modification of Ramsden’s method demonstrating the formation of mechanical surface aggregates, in an hitherto unobserved form, has been described, viz. horizontal glass tubes in parallel which are especially suitable for opaque fluids.

The condition appears to be identical with that described by Aekma and Brouwer(2) who showed the occurrence of corpuscles in milk after violent agitation. These corpuscles probably consist of thin films of solid protein which as in the cases described by the author have formed at the interfaces of air bubbles and milk.

The phenomenon has been shown to be of importance in handling dilutions of milk in the course of bacterial enumeration.

Two sets of records, for Light and Heavy Horses respectively, have been analysed statistically, with the object of studying some of the factors which affect the percentage of foals left by a stallion in a service season.

It has been found that the stallion himself is one factor, in that each individual’s percentage returns, in successive seasons, tend towards a constant figure; although there is every gradation, and even considerable variation from year to year, there are definitely good and bad “getters” of foals.

A stallion's fertility varies according to the district of the country in which he stands or travels, being higher in the north and west of England and Wales than in the south and east, and very low in Scotland.

In moderation, frequent use does not impair a stallion's fertility; there is, in fact, some (insignificant) evidence that the more mares he serves, the greater the proportion of foals he leaves.

There is a slight tendency for a stallion's fertility to rise from the time he is 3 years old till he is 13 years old—this result may, though, easily be due to chance; on the other hand it is quite clear that fertility declines after the age of 16 years, and this occurs over the whole range, and is not caused by a certain number becoming absolutely sterile.

1. The omission of the tension in the air-water interface has introduced an erroneous factor into Haines’ formulae; certain additional factors have also crept into his expressions for average stress.

2. With these corrections, the stress due to moisture varies comparatively little with changing water content, though falling slightly throughout the range. The energy needed to cause rupture rises continuously in a manner not unlike Haines’ measurements, and should more probably be associated with them than should the tensile stress.

3. The geometrical approximation used by Haines gives a close geometrical representation of the figure, but a mechanical approximation which is less satisfactory. Since neither the formulae connected with the true curve, nor the tables needed to use them, are readily, accessible, sufficiently exact numerical data have been here put on record.