1. The sperm production of a pony stallion kept a constant high level when the collection of sperms was performed regularly three times a week. There was no adverse effect on the stallion or on the quantity and quality of the sperms. There is a negative correlation between the volume of semen and the concentration. The total number ejaculated remains relatively constant; the volume of accessory fluids is more variable.

2. The motility of horse spermatozoa after dilution with eight different kinds of chemical media and stored at different temperatures was studied: Glucose-yolk-phosphate dilutor devised by Lamhert & McKenzie and glucose-yolk-tartrate dilutor devised by the author were found to be the best for the preservation of horse sperms at low temperature. There was not much difference between those diluted samples stored for 24 hr. at 10° C. and those slowly cooled to 1° C. Concentration of the semen by centrifuge is definitely beneficial for the preservation of horse sperms.

3. Pregnancies were obtained by the insemination of sperms centrifuged and kept at 1° C. for 24 hr. The sperms of one stallion can be used for a great number of mares if artificial insemination is practised. The adoption of new techniques for the determination of the time of ovulation and for the induction of ovulation is suggested for successful artificial insemination of mares.

1. A long-term investigation consisting of field, pot and laboratory experiments has been commenced to study the extent, rate, nature and significance of phosphate fixation in north Scottish soils with the ultimate objects of improving fertilizer practice and standardizing methods for determining readily soluble phosphate.

2. Quantities of a phosphate-deficient soil derived mainly from granitic drift were treated with incremental dressings of phosphate and exposed in earthenware pots in the open. The soil had an initial pH of 5·80 and a total phosphate content of 0·250% of which 28% is soluble in constant-boiling HCl solution.

3. The recovery of added phosphate by different methods from samples taken after varying periods of exposure has been studied. Data are given for extractions with calcium lactate, acetic acid, potassium bisulphate, citric acid, magnesium bicarbonate, sodium hydroxide, hydrochloric acid, and chloride and sulphate solutions, together with pot experiments and determinations by the Neubauer and aspergillus methods.

4. Complete recovery is approached only in strongly acid and strongly alkaline extracts, and about 25% of the added phosphate is very firmly bound by the soil. The solubility varies greatly with the pH of the extracts and is very low at pH values in the region of 5. At lower pH values, however, the nature and concentration of the anions present are also of considerable importance. The results indicate a high capacity for fixing phosphate in difficultly soluble form.

The present account is a sequel to an earlier publication on the composition and feeding value of potato cossettes and meal. It deals with the composition, digestibility and nutritive value for pigs and ruminants of potato flakes and slices, theresults of a large-scale pig-feeding trial with potato slices and the composition and value for pigs of potato dust, a by-product of the manufacture of potato slices. Details of the processes of production of these various dried potato products are included in the text.

1. Egyptian clover, sweet lupin, Lathyrus ochrus, Eragrostis tef and Vicia narbonnensis have been analysed as to their hexosan, pentosan and lignin content. The major part of the pentosan is soluble in 2 % HCl and therefore belongs to the hemicellulose fraction, whereas most of the hexosan is insoluble in 2 % HCl and forms part of the cellulose fraction.

2. The digestibility of hexosan, pentosan and lignin has been determined by experiments with sheep. The digestibility of soluble pentosan and of insoluble hexosan (2 % HCl) was found to be very constant. It ranged from 64·0 to 66·2 % for pentosan and from 74·1 to 76·5 % for hexosan. ·Lignin was in all cases digested comparatively well, the digestibility coefficients being markedly variable, depending on the plant material. They ranged between 35·1 and 64·0.

3. Faeces lignin yields lower methoxyl values than plant lignin. Therefore lignin appears to have been changed during passage through the animal body.

4. The partition of hexosan, pentosan and lignin on crude fibre and N-free extract prepared from different plant materials is markedly variable.

5. The major portion and best digestible fraction of plant lignin is soluble in alkali and is, therefore, contained in the N-free extract.

The blood picture for Ca, inorganic P and phosphatase during the development of rickets caused by uncomplicated vitamin D deficiency in sheep has been established. The earliest and most distinctive change was found to be in the serum Ca level.

Lambs were shown to have sufficient reserves of vitamin D to protect them against avitaminosis D for a period of about 6 weeks as judged by serum Ca levels. Rickets did not develop unless there was a moderate degree of growth and, in such cases, the serum Ca level was below 7 mg./100 ml.

The practical application of the results was discussed.

The authors desire to acknowledge the co-operation of Dr A. H. H. Fraser in the earlier planning of this work.

To study the total-life performance of all the 156 sows, they were divided into groups consisting of sows having produced 73 to 77, 78 to 82, 83 to 87, … pigs throughout their breeding life often litters. The frequency distribution, of total number of offspring born, thus obtained is shown in Fig. 2.

Mechanical peeling of potatoes removes an exceedingly thin skin that is notably richer in ether extract, fibre and lime, but much poorer in N-free extractives, than the thicker parings obtained by ordinary hand peeling. The latter, in respect of their general composition, do not differ to any marked extent from whole potatoes.

The results of digestion trials with pigs have shown that potato peelings, after cooking, are highly digestible when included in the rations of bacon pigs. The N-free extractives, which form about 80% of the dry matter of the hand peelings, have a digestion coefficient of 96·2%. An allowance of 5 lb. of such peelings supplies as much digestible organic matter as 4 lb. of whole potatoes, and it is concluded that 1 lb. of barley meal in the rations of bacon pigs may be replaced by 4 lb. of potatoes or by 5 lb. of potato peelings. Both the potatoes and the potato peelings should be cooked before feeding.

In conclusion, the writers take this opportunity of expressing their thanks to Messrs V. Thurlbourn and C. Bendall, in whose experienced hands the care of the experimental animals was placed during the digestion trials.

1. The data summarized in this paper relate to the live weight at killing, the carcass weight, the skin weight and the loss in dressing of 813 males and 289 females of various breeds and varieties of rabbit.

2. The age at killing varied with the moulting process. The extent to which variation in age contributes to the variation in weight and accounts partly for some of the differences observed is not dealt with.

3. Significant differences were noted between the live weights of the various breed groups, in both sexes.

Equipment. Simultaneous observation of the performance of several mole drains in heavy grassland requires recording flowmeters. Simple instruments recording instantaneous rate of flow have been designed and found satisfactory. A recording rain gauge is a necessary adjunct.

Plot size and edge effects. Where the land is laid up in ridge and furrow, even though rudimentary, the ridge forms an effective barrier between furrows. One drained furrow at the edge of a plot is a sufficient, but not always necessary, guard against the neighbouring plot. Where the land is farmed on the flat, a single catch-water furrow forms adequate protection.

The nature of British rainfall. Rainstorms producing drainage are almost invariably of discontinuous type, consisting of well-defined intense showers separated by periods of almost complete quiescence. Thus a storm of 8 hr. duration may consist of as many as six quite distinct showers.

1. Experiments have been made to determine the effect of treating alkaline soils with manganese sulphate on the quantities of manganese which can be extracted by N-ammonium acetate.

2. Two soils of known total and ‘extractable’ manganese content were treated with manganese sulphate solution in the laboratory and re-analysed after definite time intervals. In the first of these, a calcareous soil from the College Farm, the extractable manganese decreased for 14 days after treatment, after which time manganese was again liberated, presumably due to a waterlogging effect. The extractable manganese in the second soil, a slightly alkaline soil with a high organic matter content, increased appreciably after treatment and remained at this level for the duration of the experiment.

3. An experiment conducted in the field on a highly calcareous soil showed that the extractable manganese content down to a depth of 12 in., had fallen to its original level only 7 days after treatment. This behaviour is in agreement with the observations of other workers that there is little residual effect from manganese sulphate treatment for subsequent crops. The desirability of performing similar experiments on other soils is suggested.

4. The effect of waterlogging and steam sterilization was to increase the quantities of extractable manganese in the soils examined.

The authors wish to express their grateful thanks to Mr B. S. Furneaux, M.Sc, for the descriptions of the soils investigated, and to Dr N. H. Pizer for his valuable suggestions in the preparation of this paper. They are also indebted to Mr J. Hargrave of the Agricultural Institute, Kirton, Lines, for providing the Bourne Fen soil, and to Mr J. Tinsley, B.Sc., for pH and organic matter determinations.

1. Experiments are described demonstrating a technique for raising sugar beet seedlings under glass during the winter to provide plants for seed production after transplanting into the field.

2. The use of 24 hr. illumination for this purpose is discussed, and the effect of this illumination in resolving a heterogeneous population is described.

3. The association between the growth habit of the seeding plant and root characters, glomerule yield, weight and size, and the time of anthesis is considered in relation to the recognition of types showing B. maritima and B. vulgaris characteristics.

A comparison is made, under similar cultural conditions in pot experiments, of the behaviour of a number of varieties of wheat, barley, rye and oats on two soils on which oats had previously displayed pronounced symptoms of manganese deficiency.

All of these cereals were found to develop disease symptoms on these soils, rapid recovery from which invariably took place after the plants had been sprayed with 1% manganese sulphate solution. Variations in deficiency symptoms in the different cereals are indicated and observations on the course of the disease throughout the season are recorded for some thirty-two varieties.

An account is given of experimental work on the feeding of uncooked and cooked potatoes and sugar beet to laying stock. The available literature on the use of these foods for poultry is reviewed and an explanation is offered for the poor results which have generally followed the use of raw potatoes.

A description is given of an experiment in which there were two control groups fed on mash, two groups on 3 oz. mash and 8 oz. potatoes daily, uncooked for one group and steamed for the other, and two groups on 3 oz. mash and 8 oz. sugar beet daily, uncooked in one case and steamed in the other.

An examination has been made of the possibility of extending the routine mechanical analysis of soils down to finer particles than the conventional clay. The main conclusions reached are:

(1) Sampling depths of only 2 cm., using standard mechanical analysis apparatus, appear to introduce no new sources of error.

(2) If a constant temperature room is available, sampling times of 7 days seem to be allowable.

(3) Using special pipettes and settling vessels, sampling depths of only 2½ mm. seem to be allowable.

In the past twenty years there has been no noticeable decrease in the number of Helminthosporium infected oat and barley seed samples examined at the Official Seed Testing Station, Cambridge, and in the course of advisory practice. No reduction in the intensity of the seedling diseases caused by Helminthosporium has been noted during the first ten years under review. Formalin and copper carbonate were ineffective as seed disinfectants in reducing seedling mortality, and copper sulphate, although partially effective, had serious phytocidal effects and consequently cannot be recommended. Since the advent of the organo-mercury seed disinfectants a steady improvement in the control of these diseases has been noted, and field tests of such dressings have shown them to be eminently satisfactory. Barley straw infected with H. gramineum has been shown to be a source of secondary infection of barley seedlings.

Two samples of ammoniated sugar-beet pulp and one untreated sample have been examined. One sample was ammoniated at room temperature and an increase of 1·94 % in nitrogen content obtained. The other sample ammoniated at 10 atm. and 80° C. showed an increase of 3·47 % in nitrogen content. The total nitrogen contents were 3·30 and 4·83 % respectively.

The results of digestion trials carried out some years ago in this Institute have led to the belief that at least 6–7 lb. of young, leafy grass is needed to replace 1 lb. of ordinary pig meal in the rations of bacon pigs. More recent farm-scale feeding trials at the Harper Adams Agricultural College have given rise to the conclusion that no more than 1¼ lb. of young grass is required for this purpose when the pigs are receiving, in addition to the grass, a basal allowance of 2½ lb. of balanced meal per head per day.

The main findings of the present trials may be. summarized as follows:

(1) When ‘mineralized’, cooked potatoes are fed as the bulky supplemental food in the Lehmann system of pig-feeding, and the basal meal allowance is restricted to 3 lb. per head per day, bacon pigs are able to make as good progress, in respect both of rate of live-weight increase and economy of food conversion, and at every stage from 60 to 200 lb. live weight, as they would if kept on a diet composed wholly of balanced meal. In the present trials, pigs of about 200 lb. live weight were able to consume 15–17 lb. of cooked potatoes per day in addition to the daily allowance of 3 lb. of meal. It required, on an average, about 1030 lb. of cooked potatoes and 311 lb. of balanced meal per pig to fatten the animals from 60 to 200 lb. live weight. The cooked potatoes, when assessed on the air-dry standard of 13 % moisture, were able to replace the balanced meal on a lb. for lb. basis without detriment to the progress of the pigs, and the average saving of meal thus made possible amounted to about 225 lb. per pig, or 38·2 % of the total meal consumed per pig on the control, all-meal diet.

(2) Cooked potatoes should be introduced into the ration gradually and the allowance should be scaled according to live weight in the manner adopted in the present trials. When the amount to be fed is large, it is best to feed ‘mineralized’, cooked potatoes only during the morning and to place the basal meal in the trough towards the end of the afternoon.

The influence of two years of bare fallow on the fertility of light land exhausted by continuous cropping with wheat or barley for fifty years has been very great, the immediate result being an increase in the crop of wheat by 50% and of barley by 140% over the average yield of the unmanured plots for the ten years before the fallow was taken. A repetition of the fallow after a further period of five years of continuous cropping without manure gave a very similar result.

Whatever had been the treatment of the land during the fifty years before the fallowing, the yield produced as a result of the bare fallow fell off very rapidly in the succeeding years, when no further manuring was given. In fact, after the first two or, at most, three years the crop, of grain went much lower than it had been before any fallowing had taken place. This falling off in yield was almost equally felt on plots which had been treated with artificial manures during the preceding fifty years as on those which had been unmanured throughout.

Conscious selection is the prime means of keeping the useful qualities of domestic animals at the level they have attained, and of improving them. Valuable economic qualities mostly show the polygenic type of inheritance and therefore continued selection can improve them by sorting out those genes in a herd or breed which are.most desirable for the breeder At the presenttime there is probably not one breed in existence with quantitative characters brought to the homozygous condition. It is the great genetic variation present in breeds which enables selection to be effective in bringing out desirable economic characters.