1. Past work on muzzle patterns of individuals and of twins is reviewed.

2. A technique of obtaining muzzle prints by making plaster casts is described.

3. Using casts, muzzle patterns from one-egg and two-egg twin pairs were scored for similarity on a 1– 5 scale. Patterns of one-egg twins were significantly more similar than those of two-egg twins, and the largest part of the total variance was due to the difference between these two groups. The score distributions for monozygous and dizygous twins did not completely overlap, indicating that muzzle pattern is inherited. However, the extent of overlap observed confines the usefulness of muzzle pattern in twin diagnosis to confirmatory evidence at the extremes of the similarity scale.

4. Parts of the muzzle pattern (central groove, cell length, and cell margins) were judged on an arbitrary scale. Two-egg twins were not found sufficiently less similar than one-egg twins for the characters to be useful in diagnosis. Twins were more alike than random pairs, but significantly so only for central groove and MZ cell length.

1. Thirty-one buffalo-cows of different ages were tested for the symptoms and duration of oestrus, and the incidence of post-partum oestrus and conception. Clinical examinations of the vagina were also carried out.

2. The symptoms of heat were less intense than in cattle and there was no homosexual activity.

3. Pro-oestrus occurred in 43% of the cases with an average duration of 21.20 hr. whilst metoestrus occurred in 67% of the cases with an average duration of 19.20 hr. The average duration of oestrus was 28.47 hr.

4. The onset and cessation of oestrus were either abrupt or gradual. The phenomenon ‘split oestrus’ was observed intervening normal cycles. This was not characteristic of the individuals.

5. The average interval to post-partum oestrus was 43.80 days. The average number of silent heats per individual was 0.86. Conception took place after an average of 1.71 services whilst the breeding efficiency was 93% in the calving buffaloes.

6. Normal clinical changes in the vagina (temperature; nature and amount of secretion; picture of smear) were not reliable indicators of oestrus.

7. Further problems concerning reproduction in the buffalo are suggested.

1. Ten local Zebu cows representative of Africanowned cattle in Central Tanganyika, maintained under good African husbandry conditions, were temperatured twice daily over a period of 134 days from 23 July to 3 December, whilst the general meteorological environment was recorded.

2. The period of observations was divided into four parts, during two of which differential planes of nutrition were maintained between two groups of animals, the first and last parts being control periods when the plane of nutrition was common to all animals.

3. The diurnal variation in rectal temperature wasapproximately 99·0–102·5° F., arange of 3·5° F., whilst the atmospheric shade temperature varied about 12° F., from 64 to 76° F. at commencement of observations, and from 71 to 83° F. at the warmest period of the observations.

4. The variation within morning rectal temperatures was greater than that within afternoon rectal temperatures.

5. The low rectal temperatures in the mornings reflected inadequate nutritional level to maintain body temperature, as they were significantly increased by a moderate supplementary ration.

6. Supplementary feeding did not affect the afternoon temperatures.

7. Daily mean rectal temperature of the cows in the morning was verysignificantly negatively correlated with atmospheric temperature.

8. Rectal temperatures of ten cows' temperatures at 2 hr. intervals from 07.00 to 21.00 hr., over a period of 7 days, was positively correlated with direct sun temperatures taken 4 hr. before rectal temperatures.

9. Rectal temperatures were positively correlated with the dew-point in the morning, but were unrelated with the lower dew-point in the afternoon.

10. It is suggested that afternoon temperaturing of experimental animals of local Zebu type under African husbandry conditions might be more informative for clinical purposes than the customary morning temperaturing, owing to the lower variation.

11. It is tentatively suggested that the thermoregulatory system of local Zebu cattle may be regarded as operating a micro-adjustment mechanism to compensate for immediate variations in micro-climate, superimposed on a macroadjustment mechanism to extend the limits of operation of the micro-adjustment in accordance with seasonal trends of the macro-climate.

12. Further data are being collected to clarify these tentative conclusions.

1. A series of grazing behaviour observations on 10 sets of lactating identical twins is described. Four fortnights distributed over the main lactation period were covered. In three of the fortnights, the observations were made on six 24 hr. periods, while in the remaining fortnight the cows were observed on all 14 days.

2. Anoutstanding feature of the grazing behaviour of dairy cattle is its variability, due to external and internal conditions.

3. Of the external factors, climate (in a temperate zone) is relatively unimportant.

4. The quantity and quality of the herbage offered are of importance in modifying the grazing behaviour of dairy cattle. Under adverse pasture conditions there is, in general, an increase of total working time (grazing + ruminating): grazing time increases with scarcity of herbage and with mixed quality, while ruminating time is prolonged by poor quality grass.

5. Ruminating time is strongly dependent on the quantity and quality of the ingested grass, but the relationship is, for various reasons, obscured in a field trial such as the present.

6. The adaptation of grazing habits to new conditions is very rapid.

7. Feed requirement for milk production is the most important internal factor determining variation in the length of grazing time.

8. Inheritance × environment interactions as a source of variations in grazing times are due to the following factors:

(a) Differences amongst twin sets in lactational persistency, which presumably cause parallel differences in feed requirements.

(b) Differences in the response of high and low producing twin sets to varying pasture conditions.

(c) Non-analysable idiosyncrasies common to the members of some twin sets.

9. Twin sets graze and ruminate at a characteristic rate.

1. The numbers of Streptococcus bovis in the rumen of a heifer and a steer, each having a permanent rumen fistula, were shown to remain relatively constant within the range 105 to 107 per ml. rumen liquid (strained rumen contents) over a period of more than 3 years.

2. The numbers of Strep. bovis were little affected by the change in diet from stall-feeding (oats, beans, hay and straw) to grass or vice versa.

3. There was a slight increase in the numbers of Strep. bovis following each meal when the animals were stall-fed, but no appreciable variation in numbers throughout the day when the animals were at grass.

4. Strep. bovis has also been isolated from the rumen of freshly slaughtered cattle and sheep from different parts of the country, from the rumen of goats and calves and from the faeces of cattle, goats and in small numbers associated with Strep. equinus from horse dung.

5. Strep. bovis was found in the contents of the omasum, large intestine and caecum of three cattle, but in the small intestine of only one of these animals. Very small numbers of Strep. bovis were detected in the abomasal contents of only four of twelve animals examined.

6. The characteristics of these strains of Strep. bovis have been described. The synthesis of an iodophilic polysaccharide by Strep. bovis has been demonstrated.

7. A possible role of Strep. bovis in the decomposition of starch and other carbohydrates in the rumen is discussed.

1. The solubilities of calcium, magnesium and phosphorus in bran, wheat, oats and certain mineral supplements have been determined at pH values between 6·5 and 1·0.

2. The solubility of calcium in calcium carbonate varied with the cereal present, but it was always completely soluble at pH 3·0 and below.

3. The calcium present in bran and wheat was not readily soluble; that in oats was fairly readily soluble.

4. Magnesium dissolved more readily at higher pH values than calcium.

5. Phosphorus in bran (with or without added calcium), and that present as pure salts, was almost completely dissolved at pH 3·0 and below, but very low phosphorus solubilities were found at these pH values in oats and, to a lesser extent, wheat.

6. These results have been considered in relation to the acidification of food which occurs in the true stomach.

Between 1946 and 1950 multifactorial field experiments were carried out to determine the potentialities and effectiveness of chlorinated phenoxyacetic acids for the selective control of weeds in linseed (oil flax). The initial experiments of 1946 demonstrated that treatment with sodium 2-methyl-4-chlorophenoxyacetate led to considerable increases in the yield of seed through a reduction of the weed population and the consequent decrease in weed competition.

The subsequent experiments were undertaken on relatively weed-free crops so that the direct effects on the crop of compound, formulation, and stage of growth at the time of application could be investigated along with differences in varietal response. Amongst the observations made were time of flowering, straw length, the yield of seed, capsule production, seeds per capsule and the weight, oil content, protein content and germination capacity of the seed.

At similar dosages sodium methylchlorophenoxyacetate is less phytotoxic than sodium 2, 4-dichlorophenoxyacetate while the parent acid and particularly the ethyl ester of the dichloro - compound are much more injurious. With sodium methylchlorophenoxyacetate the tolerance is greatest between the post-cotyledon stage and a height of 20–25 cm.; within this range of plant development dosages up to 3·5 lb./acre have no adverse effects on the yield of seed. Treatment within 2–3 weeks of flowering delays flowering and reduces the seed weight. When dichloro-compounds are employed there are additional effects, such as the formation of abortive capsules or a reduction in the number of seeds per capsule. Under some conditions the oil content and the germination capacity of the seed is depressed but the protein content is increased.

1. The development of the fleece and follicle population was studied in six Herdwick and two Herdwick × Swaledale sheep on their native farm in Cumberland. Six of these sheep survived the first 14 months of the experiment, and four were kept under observation for a further 12 months. Growth in body weight, body surface area, and area of tattooed squares was recorded and discussed.

2. Fibre type arrays (at the mid-side positions) were ‘Plateau’ in all but one of the pure Herdwick lambs, and ‘Saddle’ in the remaining three animals.

3. The earliest fibres of the array (halos and coarse super-sickles) were mostly ribbon-shaped in their pre-natal and early post-natal portions, below which they became cylindrical. These fibres were ‘birth coat kemps’ and were shed about 10 weeks after birth. At this time later-developed fibres (sickles and curly-tips) showed ‘crisis thinning’ but did not shed, whilst late curly tips and histerotrichs were not affected. These three groups gave rise to three corresponding groups of fibres in the adult fleece, namely kemps, hairs and fine fibres.

4. Two generations of kemp fibres were grown each year, ‘spring kemps’ commencing growth about April and shedding by July; and ‘autumn kemps’ commencing growth in July and forming ‘brush-roots’ in the autumn and early winter, although the majority remain in their follicles until the following spring.

5. The majority of the curly tip fibres of the birth coat grow into long hair fibres, which are of hetero-typical shape. In summer they are more or less coarse, and medullated, whilst in winter they become fine and lose their medulla; many cease growth during the middle of the winter period after producing a short length of fine fibre, and commence growth again in the spring. The late curly tip and histerotrichs fibres continue to grow as the fine undercoat fibres of the fleece, without any medullation.

6. A large proportion of both primary and secondary follicles shed their fibres during the winter months. When this proportion is sufficiently high this leads to a severe ‘winter break’ in the wool staple. The visible ‘break’ is the result of the combined effect of the winter fining of heterotype hairs and the shedding of some of all types. Fibres traversing the break were found to be either long heterotypes or long fine fibres.

7. The adult colour of any individual Herdwick sheep is the result of the interaction of several factors of which the main ones are: (1) later fibre types tend to be less pigmented than early types; (2) less vigorous growth of an individual fibre tends to reduce its pigmentation; (3) a more or less extensive acromelanic pigmentation; (4) the white areas may be affected by various degrees of speckling or roaning; (5) the kemp-like hairs of the face and legs are black at birth, and these are eventually shed and replaced by similar but unpigmented fibres.

8. Numerical data on the fibre and follicle population are presented. The mean proportion of the three main fibre types (all sheep, all seasons) was: coarse 18%, medium 25%, fine 59%. The mean adult follicle density was 1012 per sq.cm. and the mean adult S/P ratio was 3·37:1.

1. Tests have been carried out to investigate the hydrolysis of phytate in wheat, bran, and oats.

2. Oats showed practically no phytase activity.

3. Wheat phytase had an optimum pH of 5·0–5·1 and functioned at pH values down to 3·0. When hydrolysis had been arrested by acidifying to pH 2·5 for 5 min. or longer, the phytase did not recover when the pH was raised to 5·0 by the addition of sodium bicarbonate.

4. There was an almost uniform increase in the rate of hydrolysis between 15 and 50° C.

5. The rate of phytate hydrolysis decreased as the reaction proceeded, but the reaction continued until only a very small amount of soluble substrate remained.

6. The presence of calcium, under conditions in which it could form insoluble phytate, reduced phytate hydrolysis to a considerable degree.

7. These reactions are considered in relation to phytate hydrolysis in the digestive tracts of animals.

1. An analysis has been made of the production records of over 1400 heifers got by A.I. bulls at five non-Board centres. The A.I. heifers, when compared with other heifers in the same herd in the same year, showed no significant increase in yield but a significant increase in fat content.

2. The difference in yield between A.I. and contemporary non A.I. heifers was not significantly different in herds at all levels of production. This would suggest that only a small proportion of the differences in yield between the herds in the sample was genetic in origin. In fat percentage, there was some evidence, though not very conclusive, that rather more of the inter-herd variation was genetic.

3. Significant differences were found between the progeny groups by different sires in both milk yield and fat content. The standard deviation of the variation due to the breeding value of the sire was 37 gal. and 0·13% fat respectively.

4. Methods of interpreting progeny tests made under A.I. conditions are discussed theoretically. It is concluded that the comparison with heifer contemporaries in the same herd is most satisfactory for milk yield and the simple average is best for fat content.

5. The relevance of these results to the genetic structure of breeds is discussed. They are in good agreement with the conclusions from pedigree analysis that the genetic differences between the dominant group of herds and the mass of commercial cattle in each breed is not great.

1. The precipitation of calcium, magnesium, phytate phosphorus, and non-phytate (chiefly phosphate) phosphorus has been determined in ‘hydrolysed’ and ‘unhydrolysed’ bran, with varying amounts of added calcium as calcium carbonate.

2. It was found that calcium phytate was precipitated before non-phytate (chiefly phosphate), whatever level of calcium carbonate was added.

3. Precipitation began and was more complete under more acid conditions when calcium and Ca: P ratio were high.

4. Similar experiments have been carried out using salt solutions containing calcium and phytate, calcium and phosphate, and calcium, phytate, and phosphate. The results were similar in most cases to those of corresponding bran mixtures.

5. The above results have been considered in relation to the precipitations which are likely to occur in the small intestine, and the possible effects of these precipitations on absorption are discussed.

This paper, which forms part of a series of investigations on the potato crop, presents evidence obtained from experiments reported in the literature on the relation between seed rate and yield of maincrop potatoes. The available experiments are sufficient to indicate what is the average relationship between seed rate and yield, but are insufficient to demonstrate any clear differences between different parts of the country, soil types or even different varieties.

Using this average relationship, optimum seed rates are presented for a range of prices of seed and produce. These optimal rates are compared with estimates from surveys of the actual amounts planted by growers in different parts of the country.

Provided the optimum seed rate is attained the precise combination of seed size and spacing distance appears to be of minor importance; that is, a grower should aim to plant at the optimum seed rate regardless of seed size. There is, however, an upper limit of spacing between sets which should not be exceeded however large the seed may be.

The optimum rate of planting at 1952 prices of ‘A’ or ‘H’ certificate seed is estimated to be 16–17 cwt. in most of the main potato-growing areas of the country, though it may be a little higher where a grower has a market for once-grown seed. Surveys indicate, however, that the normal planting rate of certified seed is over a ton to the acre in these districts.

For a grower's own once-grown seed, on the other hand, for which the cost is not more than the price received for ware, the optimum seed rate is at least one ton per acre, whilst the average weight of seed actually planted is only about 17 cwt. per acre. It is estimated that the average loss per acre due to this failure to plant at the optimum seed rate amounts to 20–25s. per acre planted with certified seed and 10–15s. per acre for once-grown seed.

In order to form a basis for any improvements of cattle and pasture management in East Africa it was decided to observe the grazing habits of the local cattle. A review of the literature shows that animals' habits can be influenced by temperature, but no record could be found to indicate the effect on the animals of elevation and an equable climate.

A summary is given of the results obtained during 720 cow-watching hours. Comparing these results with those obtained by other workers it is clear that Bos indicus cattle on a high-level plateau under tropical conditions have distinct and unique habits. On the average, during days with 12 hr. daylight 7·7 hr. were spent in grazing, 93% of this time being during daylight; 5·2 hr. were spent in ruminating, only 23% of this being during the hours of daylight.

1. The solubility of phytate in the presence of protein has been determined over a pH range 6·5 to 0·5.

2. The fall in solubility of phytate in the region of pH 2·5 is shown to be due to a reaction with protein.

3. The reaction could be reduced considerably by adding calcium.

4. The mechanisms of these reactions are discussed.

Detailed investigations on identification and classification of lucerne varieties and strains were conducted at Cambridge for four years, 1949–52, on lucerne sown in row plots and on twelve typical varieties planted out in replicated trials as single spaced plants, using 200 plants of each variety. A number of physiological and morphological characters were examined and the resulting data was analysed statistically.

The characteristics used for classification are those which showed considerable variation between varieties, but at the same time these differences were maintained consistently from year to year. They proved to be unaffected by a different way of growing the plants or by small differences in soil fertility or season. The results are shown in Tables 1–17, and three basic classifications with distinguishing features of types and varieties are given. The correlations established between various characters on twelve varieties are given under the heading ‘Correlations’ at the end of the results.

(a) The first classification into early, mid-season, late and extra-late types, based on the time of flowering, spring and autumn growth, gives a fair indication to the growers regarding earliness and productivity of various varieties.

(b) The behaviour of certain varieties from South America, and in particular Saladina, an Argentine variety, which is vigorous and productive under native country conditions but has lost this ability under Cambridge conditions, indicates plainly that classification based on these three characters can be applied only to the country under whose conditions it was established. Therefore any variety especially obtained from a country of extremely different environmental conditions and management system should be checked in these respects even if a description is given.

1. Follicular fluid was collected by aspiration from the ovaries of cows which had been treated with pregnant mare serum, and were killed 3–4 days after heat.

2. Various chemical determinations have been carried out with samples of follicular fluid which, amongst others, was found to contain 39–43 mg./ 100 ml. of glucose, between 13 and 95 mg./100 ml. of lactic acid, and 0·8–3·0 mg./100 ml. of ascorbic acid.

3. The effect of follicular fluid upon sperm fructolysis was examined; however, no effect other than that due to the glucose content of the follicular fluid, could be observed.

A two-row hand-dropping potato planter was modified by adding fertilizer equipment. The machine was used in thirty-three experiments in 1951 and 1952 to plant potatoes from flat land and compare broadcast dressings of granulated compound fertilizer with dressings placed near to the seed.

Fertilizer placed either in one band at the side and below the level of the seed, or in contact with the seed, gave consistently higher yields than broadcast dressings. Broadcast fertilizer gave yields similar to those given by only one-half to two-thirds as much placed fertilizer. On the average of all the experiments, placing fertilizer gave about 1 ton/acre more potatoes than broadcasting. The advantages of placement were greatest when low rates of dressing were used.

Broadcast fertilizer was cultivated deeply into the seed-beds in nineteen experiments in 1952 and gave slightly lower average yields than late dressings broadcast on the seed-beds.

Fertilizer placed in bands on the soil surface immediately in front of the seed-shoes gave yields similar to those given by dressings broadcast over the seed-beds in fourteen experiments in 1951. In average planting conditions fertilizer broadcast on the seed-beds or placed in front of the seed-shoes was thrown to the middle of the ridges and concentrated above the seed.

Fertilizer placed in contact with the seed gave higher average yields than dressings in a sideband at both rates of manuring in the 1951 experiments. In 1952 contact placement was slightly superior to sideband placement at low rates of fertilizer and slightly inferior at high rates. In most experiments in each year emergence was delayed by 10–14 days when the heavy dressing was placed in contact with the seed. Early growth was poor but at most centres the crops recovered later in the season and gave good yields. There is most risk of damage from contact placement on light soils, on badly prepared seed-beds and in dry years. Dressings of 10 to 12 cwt./acre of ordinary-strength compound fertilizers are likely to be quite safe when applied in contact with the seed. If heavier dressings are to be used, part should be applied in contact with the seed and part broadcast, such split applications were satisfactory in experiments in 1951.

Farmers planting even moderate acreages of potatoes by machines will benefit by using a suitable fertilizer attachment. Equipment is needed to place fertilizer at the side of the seed so that heavy dressings can be used to secure maximum yields without risk.

A short account is given of 7 years' breeding for high and low brooder-house viability in a White Wyandotte flock, in which mortality, to 8 weeks of age in most years, varied from almost 50% in the early years to 10% in the last year (1947). When separate sections of the flock were established, the lowviability section showed consistently greater rearing losses than the high-viability section.

Brooder house viability appeared to have a relatively low additive heritability, when estimated from such of the records as were suitable, the pooled estimate from differences amongst sires' progenies being only about 0·07. There was definite evidence that mortality was affected by the common maternal origin of full sibs, the heritability estimated from differences amongst full-sib progenies of dams mated to the same sire being significantly higher than that estimated from differences amongst the half-sib progenies of the sires.