1. Construction and details of operation of a respiration chamber suitable for studies on the laying hen are described.

2. Calorimetric data on the utilization of food energy from balanced rations and from glucose are given.

3. The net energy of balanced rations for maintenance and production is 83·7% of the metabolizable energy. The figure for glucose is considerably higher.

4. The maintenance requirement of the 2 kg. laying hen is 88·9 kcal. metabolizable energy/kg./day.

5. Some comments are given on the significance of protein metabolism in relation to the use of indirect calorimetry for avian species.

Certain relationships between linear live animal and carcass measurements and the quantitative composition of the half-carcass have been established.

Of the live linear body measurements taken, the length of the fore-cannon bone and length of the hind leg appear to have close relationship with carcass measurements. Live fore-cannon bone is a good index of the total weight of bone in the halfcarcass and therefore has application in the selection of meat sheep.

Of the carcass measurements studied, length of fore-cannon bone and length of tibia + tarsus (T) appear to be satisfactory predictors of the total weight of bone.

An experiment was conducted to investigate the relationship between specific gravity and total fat content of the half-carcass. Specific gravity was found to be highly but negatively correlated with the percentage of fat in the half-carcass

(r = −0·9841, P < 0·001).

It was also found that the sample joint is a satisfactory index of fatness of joint as well as that of the half-carcass.

1. Four experiments designed to investigate the effect of fertilizers on the rate of bulking of Majestic potatoes are described and the results discussed.

2. Irrespective of fertilizer application yield increased until the haulm died and then decreased slightly.

3. Sulphate of ammonia increased the yield by increasing the number of tubers and increasing the yield in all size-grades. Thus its effect was seen throughout the season, no matter what grades yield was based on. It also increased dry-matter percentage.

The paper deals with points arising in the design of factorial schemes for incorporating fertilizer and other treatments in rotation experiments. These schemes make extensive use of fractional replication and confounding, including split-plot confounding. They are complicated by the need to apply some treatments cumulatively and others with levels changed between plots in successive cycles so as to minimize errors due to constant plot differences.

Design keys are used to identify the treatment main effects and rotation differences with particular plot contrasts. The keys exhibit the structure of a design more compactly and clearly than a complete enumeration of identities and confounded contrasts and enable treatment combinations to be generated systematically.

Two sorghum varieties, Dobbs and Bukura Mahemba, were grown in Tanganyika over a wide range of sites, seasons and naturally occurring levels of Striga infestation. Dobbs showed good Striga resistance relative to Bukura Mahemba: In Dobbs there were 9% of the number of witchweed plants above ground as against Bukura Mahemba. (3200 to 37,200 Striga plants per acre): The grain yield of Bukura Mahemba (845 lb./acre) was adversely affected by the Striga. That of Dobbs (1325 lb./acre) was not.

The experiment testing N residues (made on a clay-loam soil) clearly showed that N applied for potatoes benefited the following wheat crop, but that N applied for wheat benefited the following potato crop little. There were no worth-while 1. An experiment on a clay-loam soil measured responses to three amounts of nitrogen on alternate crops of wheat and potatoes; these dressings were tested in all combinations with three rates of N applied 1 and 2 years previously. Nitrogen applied for potatoes consistently increased yields of following wheat. The residue from applying 1·5 cwt. N/acre for potatoes was equivalent to topdressing the wheat with 0·55 cwt. N/acre; the value of the residue was decreased by applying N to the wheat. Potato yields were increased little by applying N to the preceding wheat crop and the residues were of little significance when compared with the responses to new N. There was no gain from N applied 2 years previously for either crop.

1. Data are presented to show that, in the United Kingdom, soil temperatures do not fall more than a few degrees below freezing point even during prolonged spells of abnormally cold weather.

2. Two methods of assessing cold resistance in cereals are described in which the natural gradient between air and soil temperature is maintained. These involve the use of seed boxes 6 in. deep in one case and a portable field freezing cabinet in the other.

A series of forty-two factorial field trials in 1959–62 tested the effects of 0·6 and 1·2 ewt./acre of N; 0, 1·2 and 2·4 cwt./acre of K2O; and 0, 2 and 4 cwt./acre of salt on sugar beet. Extra plots received 0 and 1·8 cwt./acre of N.

On average, 0·6 cwt./acre of N was more profitable than 1·2 cwt./acre. There was a positive interaction between N and Na, and a lesser one between N and K; in presence of the heavy salt dressing, or the light salt dressing and potassium the optimum rate of nitrogen was 1·0 cwt./acre.

In a series of experiments in which variations in the level of carbohydrates in the plant have been brought about by means of short-term exposures to darkness and raised temperatures, it has been shown that:

1. The yield of leaf material after cutting is affected by pretreatments. This effect seems to be at least partly associated with the level of carbohydrates present in the stubble at the time of cutting.

2. The rate of growth of the plants is independent of the pretreatments imposed once growth is fully established.

The physical wool characteristics of 268 Iraqi Awassi ewes were studied in 1963, as well as the relationship between some of these traits. The overall average grease fleece weight, clean wool percentage, staple length, fibre length, fibre diameter and degree of crimp were 3·77 lb., 84·85%, 16·47 cm., 17·37 cm., 33·32/t and 4·18 crimps per 2 cm. respectively. These attributes class the Awassi wool as a carpet wool.

Age proved to have no significant effect on any ofthe traits examined. Significant positive correlations were found between grease fleece weight and fibre length and between number of crimps and fibre diameter, while a significant negative correlation was found between clean wool percentage and fibre length.

1. Groups of twenty-four heifers were used in three experiments lasting 51–98 days. The effect on rate of live-weight gain of the addition of 150 ml. cod-liver oil to the daily ration was studied.

2. The same treatments were used in each experiment: a basal diet consisting of hay and concentrates and two experimental diets consisting of the basal diet plus (a) 3 lb. concentrates, (b) 150 ml. (0·30 lb.) cod-liver oil. In one experiment flaked maize was used in the concentrates in place of crushed barley.

1. Cuts of elephant grass (Pennisetum purpureum were made at 40–60 (trial 1), 30 (trial 2), 50 (trial 3) and 70 (trial 4) days of age. Determinations of voluntary intake, digestibility coefficients, rate of passage through the gut, time spent eating and ruminating, number of boluses, rate of chewing, production of volatile fatty acids (both total and individual) were determined using individually housed sheep.

2. Digestibility coefficients of crude protein declined with the level of crude protein in the forage; digestion of the crude fibre fraction declined with advancing maturity. The digestibility of N.F.E. increased with increasing maturity resulting in similar values for T.D.N. among the four cuts. Digestibility of dry matter of the grass in trial 2 was significantly higher than that for the other three trials.

1. Loss of ignition at 450°C. and the organic carbon content of some shale soils are positively correlated (r = +0·99).

2. Base exchange capacities and exchangeable cations were determined on soils, treated and untreated with hydrogen peroxide solution.

3. Oxidizing the organic matter lessened the exchange capacities of all samples; the exchange capacity of the organic matter varied from 67·5 to 97·0 m-equiv./1OO g. dry material.

Yields of varieties of red clover were found to vary from year to year and relative to each other.

Apart from losses in harvesting the seed, which were not studied, yields of seed were found to be correlated with seed set, size of seed and numbers of heads in the crop. In 1958 the dominant factor affecting yields was Kabatiella.

Because of the value of seed set in indicating potential yield, its relation to other characters was studied. Data are given for length of corolla tube, numbers of positive pollinators and size of head as indicated by the number of florets, and their relationship to seed set and to one another.

Investigations have been made of boars yielding spermatozoa with a specific morphological (‘knobbed’) defect of the acrosome.

Counts were made of the number of knobbed spermatozoa in pairs of nigrosin eosin smears made from the semen of normal boars, in the semen of two (‘affected’) full brothers with ejaculates known to contain a high proportion of knobbed spermatozoa, and in mixtures of normal and affected ejaculates. Few or no knobbed spermatozoa were recorded in the semen of normal boars. Virtually all spermatozoa from the affected boars were recorded as knobbed. Counts on mixed samples agreed well with expected values.

Fifty Boran Bos indicus steers, all of which were born during the same months, were reared together on grass without supplementary feeding, until required for slaughter. Pre-determined randomly selected groups of these steers were slaughtered at 1½, 2½, 3½, 4, 5 and 5½ years of age. Carcass analyses were carried out and the changing relationship between the edible carcass components themselves and of their relationship to live and carcass weights during growth were investigated. It was observed that certain components maintained a near constant relationship to each other throughout growth. It was also noted that compensatory growth of light-weight weaners enabled them to be as productive, in terms of final carcass weight and composition at 3½ and 4 years, as heavy-weight weaners.