The results indicate that the usually accepted methods of sampling mangel roots by means of horizontal cores in a north-south direction through the largest diameter of the root or one-third way down from the crown, are subject to greater inaccuracies than similar cores taken twothirds to three-quarters way down, which gave consistently samples of satisfactory accuracy.

Our best thanks are due to members of the College StafE for helpful criticism of all stages of the work, also to the Edinburgh and East of Scotland College of Agriculture for a detailed description of technique and apparatus in use for their work on dry matter in root crops.

1. During the fermentation of water-logged soil containing added substances with different carbon-nitrogen ratios, the reaction first turns slightly acid, but soon returns to the original hydrogen-ion concentration (pH 7·6).

2. The quantities of ammonia present in the medium increase up to a point, after which there is steady decrease.

3. There is nitrification only in the case of substances with narrow C/N ratios. The production of nitrate generally commences only after about a month, when the vigour of the initial fermentation has subsided and fairly large quantities of ammonia have accumulated in the medium.

4. The extent of mineralisation of nitrogen is determined chiefly by the C/N ratio, though in the cases of substances like mahua and lantana the presence of other constituents may also influence the processes. The quantities of mineralised nitrogen present in the soil system generally tend to decrease after about two months.

The results of experiments conducted on 156 swine, from time of weaning till bacon weights were reached, are reported. One hundred and twenty of these animals were subjected to complete dietary control as regards the quantity of food consumed and the composition of the diet.

Twenty-nine treatments, consisting of different amounts of Ca, P and vitamin D added to an otherwise adequate diet, were imposed.

The reaction of the animals to the treatments was studied in relation to growth (increase in weight), appetite, utilisation of the food, the blood picture (concentration of serum Ca, blood inorganic phosphate, serum phosphatase and blood Hb), and the morphology and chemical composition of the bone. The results obtained are summarised in Table XVIII.

In this paper, which is the third of a series dealing with the nutritive properties of the lucerne crop, an account is given of the results of an investigation into the composition, digestibility and nutritive value of lucerne hay, lucerne meal and lucerne leaf meal.

Three samples of lucerne hay were dealt with, the first two having been made by baling direct from the field and the third by the usual procedure of filling into the stack. It is shown that by baling from the field, it is possible to conserve forage at a higher moisture content than would be considered safe when filling the material into a stack. In such circumstances, however, too tight a compression of the bales should be avoided, since if the process of partial drying-out during storage be retarded by over-compression, there is danger of extensive mould development and spoiling. It is advisable that the bales should be stored under good cover and in such a manner as to permit of free circulation of air between them. The hay from the bales was of much poorer quality than that made in the stack.

This study treats of the progress in the milk production of a cow during a single lactation, and the relation of this trend to various factors associated with the particular lactation. The analysis is based on the monthly milk production records of all cows having six or more lactations, in a single large herd of pure-bred Jerseys. The herd provided records on ninety-nine such cows having a total of 679 lactations. Since the trend in the amount of milk produced in a lactation may be described by a simple exponential curve, this equation was fitted to the first 8-months’ production records for each of the 679 lactations. From these curves, constants were obtained which measure for each lactation: the theoretical initial yield; the decline of milk yield with time, or in other words the persistency rate; and the scatter of the observed monthly yields about the smooth curve. It is these constants which were studied relative to certain general and biological factors.

Feeding stalls of the Lehmann type, which are generally employed when sheep are used for digestibility trials, are useful if wethers act as experimental animals. The wether, however, is not an ideal subject for investigations in which it is desired to estimate the utilisation of individual nutriments, for the portion of the ration which is retained usually constitutes but a small part of that ingested and, in consequence, when attempts are made to draw up a true balance considerable errors are often encountered through the difficulty of ascertaining the total volume of urine excreted during the feeding period. This uncertainty may be overcome, for if the ewe is used a catheter may be passed into the bladder and the urine completely drained at the will of the experimenter.

1. The question whether the amount of cystine in the wool grown may exceed that in the diet is discussed.

2. When 1 gm. of laevo-cystine was added to the daily ration of a ewe on a low protein diet, the wool grown upon a circumscribed area was 14 per cent, more than that grown during a similar period immediately preceding. Four-fifths of the sulphur in the added cystine was absorbed, about half of which was excreted in the urine during the period the cystine was being fed.

3. When 1 gm. of laevo-cystein was injected subcutaneously each day for 10 days, a 34 per cent, increase in wool growth occurred. During three succeeding periods, of 10 days each, immediately after the injections had been discontinued, the increases were 30, 18 and 7 per cent, respectively. Of the 2.6 gm. of sulphur in the cystein injected during the 10 days, 1.7 gm. was retained and could be accounted for by the extra amount of wool grown during that and the succeeding periods.

1. In pot culture experiments with barley and mustard conducted in several soils over a number of years, the yield differences between calcium cyanamide and ammonium sulphate were generally small. Calcium cyanamide gave slightly poorer results than ammonium sulphate in soils with high responses to added nitrogen but definitely better ones in soils which contained much available nitrogen and in which calcium cyanamide greatly retarded nitrification.

2. The pot culture experiments confirmed the conclusion from earlier laboratory work that in normal soils calcium cyanamide was converted through urea into ammonia within a few days. Nitrate accumulation was less complete and slower from calcium cyanamide than from ammonium sulphate. In one soil the nitrogen from calcium cyanamide remained as ammonia for several weeks, the nitrate content being below that even of unmanured soil.

The cause of variation in the live-weight increase of animals on experiment has been further investigated. It had been shown previously that varying food intakes and initial weights-inherent drawbacks of the group-feeding method-accounted for much of this variation. When these two factors are rigidly controlled small differences in live-weight gains are still obtained. Evidence is presented to show that the basal metabolism and the digestive capacity of animals are for all purposes the same, and cannot account for any great part of the residual variation.