The influence of rainfall during the growing season on the yield of the Park Grass plots at Rothamsted, which are cut for hay every year, has been investigated.

The average yields in the period 1858–1902 on the thirteen plots examined were from 18 cwt./acre on an unmanured plot to 61 cwt./acre on a plot receiving a complete fertilizer including a heavy dressing of nitrogen. All the plots showed some deterioration in yield. The effect of the total amount of rainfall from 5 March to 8 July was very substantial on all plots, the average increase in yield for each additional inch of rain varying between 0·7 and 2·4 cwt./acre; the benefit was greatest on the plots dressed with sulphate of ammonia. The rainfall effects reached a maximum in the latter part of April and early May, but the distribution of the rain appeared to be of relatively small importance.

A statistical experiment was made on May King lettuce grown in a gravel soil in the unheated greenhouse to ascertain the effect of periodic sowings, two levels of water, and alternate drought and saturation with water on bolting and growth.

Mature lettuces at a low level of water were darker than those at a high level. The total numbers bolting irrespective of treatment were highest in May to July, and this period coincided with temperatures above 60° F., long days, and decreasing ages from germination to bolting; the largest lettuces were harvested in October to May (excluding mid-January to late March), a period of low temperatures less than 60° F., short days, and increasing ages from germination to harvest.

Statistical experiments were made to ascertain the effect of variations in applied soluble phosphate on the growth of Milan Strap-leaved Purple Top Turnips in a light gravel soil already containing sufficient available phosphate, and in a fen soil possessing an inadequate supply of available phosphate, as aggregates for growth.

No adverse effect on yield, calculated as fresh or dry matter of tops, roots, or whole plants, was suffered in either soil at any of the stages of growth considered at the highest concentrations of soluble phosphate, unlike the behaviour of this turnip when grown in a pure sand containing no clays or humates, where there was a narrow optimum range of phosphorus at a low concentration. The gravel soil occupied an intermediate position, however, between sand with its low optimum range of soluble phosphorus, and fen soil, where positive response to increasing concentrations of soluble phosphorus approached the ‘normal’, and thus there was a range of phosphorus at low concentration tending to a maximum yield followed generally by a greater numerical yield at the highest concentrations of phosphorus.

At the seedling stage in gravel soil variation in applied phosphate had absolutely no statistical effect on yield, moisture content of tops, roots and whole plants, and the ratios, for fresh or dry matter, Top/Root, Root/(Whole plant) and (Whole plant)/ Top.

1. Chemical analyses have been carried out on the muscular and fatty tissues from thirty-one beef animals and twenty-nine lambs, and also on the psoas muscle from twenty-nine pigs. The animals were selected to represent a very wide cross-section of our meat industry.

2. The water content of muscular tissue (psoas muscle), calculated on a fat-free basis, was found to be the same for cattle, lambs, and pigs (immediately after death), the average being about 78%.

3. Similarly, the original water-content of the fatty tissue (perinephric), calculated on a fat-free basis, was found to be the same for cattle and lambs, being on the average about 81–82%.

4. The average water-content of boneless meat (i.e. the combined muscular and fatty tissues from a whole side or carcass) was the same for cattle and lambs, being about 79% (on a fat-free basis), shortly after death.

5. In all these cases there was no significant difference between the different species.

The extent of the change in pH on incubation, when bull sperm were suspended in various fluids of different composition, was affected by the buffer capacity, the pH, and the glucose content. In one such fluid, used to replace seminal fluid, there was a highly significant positive correlation between the pH. change and the number and motility of the sperm, and between the pH change in this fluid and in undiluted semen. The various conditions which appear to affect the increase in acidity are discussed, and it is concluded that there is no practical object in determining the change in pH on incubation in an artificial fluid of uniform and constant composition, instead of in semen.

1. The seeding rate of radish seed may be influenced by the mechanical effect of the material with which it is treated.

2. The seedling emergence of radishes may be improved by treating the seed with an organomercury seed disinfectant.

3. The beneficial effect is correlated with adverse weather conditions at the time of germination, and advantages are therefore usually confined to early sowings.

1. Treatment of seed beans with an organomercurial dressing has been shown to have little or no effect on growth and yield.

2. Experiments have shown that the emergence of ‘weevilled’ beans is markedly less than that of sound beans for both winter and spring sowings.

3. It is suggested that the reduced emergence of weevilled beans is due to beetle injury of the seed and not to invasion by soil organisms.

In this paper are presented the results of an investigation into the composition and digestibility of fodder cellulose. This product was manufactured from wheat straw by the method employed in the making of paper. Wheat straw was boiled with 5·9% caustic soda solution for 7 hr. under a pressure of 70 lb./sq.in. The alkaline liquor was then run off, and the residual cellulose, after being washed with water until free from alkali, was pressed, dried in electric ovens at 100° C. and finally obtained in the form of a coarse meal. It contained, on the basis of dry matter, 79·82% of crude fibre, 16·22% of N-free extractives (mainly xylan), 0·36% of crude protein, 0·49% of other extract and 3·11% of ash. Its content of total cellulose (‘true’ cellulose plus associated cellulosan, as defined by Norman & Jenkins, 1933) amounted to 97·4% on the moisture and ash-free basis.

Digestion trials were carried out with both sheep and pigs. The daily ration of the sheep consisted of 800 g. of chaffed meadow hay, 600 g. of fodder cellulose, 100 g. of linseed cake, 60 g. of molasses and 18 g. of a mixture of equal parts of common salt and precipitated tricalcic phosphate. Although the fodder cellulose formed as much as 38% of the total daily food, no difficulty was experienced in securing clean and ready consumption.

An account of the agricultural conditions which influence the development of stem-end blackening in cooked potatoes has recently been given (Wager, 1946). The evidence given by Smith, Nash & Dittman (1942) shows that the average air temperature for the three weeks preceding the lifting of the tubers, or the death of the tops, controls the development of stem-end blackening in the tubers and the authors claim that this is an overriding factor. In their experiments, extending over several years, little or no blackening developed when the average air temperature was between 70 and 80° F., when between 60 and 70° F. there was a medium development of blackening and when between 50 and 60° F. there was much blackening.

1. In studying the factors influencing the ‘easily reducible’ manganese in soils, results were obtained to indicate that the estimation is dependent on the pH of the system, the nature of the salt solution, the nature of the reducing agent and the time of contact, in addition to the amount and nature of the higher oxides of manganese present.

2. Pyrolusite (MnO2) and a synthetic preparation of manganite hydroxide are ‘easily reducible’ oxides, while manganite (MnO(OH)) and naturally occurring hausmannite (Mn Mn2O4) are apparently ‘difficultly reducible’ forms.

3. Since pyrolusite occurs in the easily reducible fraction, those deficient soils which contain only a small proportion of their manganese in the easily reducible form must contain the larger part in a form less reactive than pyrolusite.

1. During the course of the alkali fractionation and the preparation of the humic precipitates, the qualitative characters of the fractions were followed by employing a standard hydrolysis with dilute acid. Humic acid itself was shown to be unhydrolysed by this reagent, and, therefore, the extent of hydrolysis of a humic fraction can be used as a criterion of purity.

2. Studies on the fractionation of the humic precipitate with aqueous, anhydrous, and alcoholic bases, led to the following conclusions:

(a) The humic precipitate as normally prepared i s always a mixture of true humic acid with varying amounts of co-precipitated material of a non-humic nature.

(b) This non-humic material is not an integral part of the humic molecules, it is merely co-precipitated and adsorbed contaminants.

(c) The non-humic material is differentiated from the humic acids by the following properties: (i) it is hydrolysable with acid; (ii) it does not give the characteristic nitro-humic compound on nitration.

The fodder cellulose used in this investigation was prepared from wheat straw by the factory process described in the preceding communication. It was dried and milled, so that the resultant material was light and fluffy in character, with the fibres well frayed. This was considered to be important, since the physical state of the cellulose might exert a considerable influence on the ability of the intestinal bacteria to bring about its fermentation and breakdown.

It was shown in the preceding paper that the fodder cellulose, on the basis of dry matter, contains 79·8% of crude fibre, of 85·1% digestibility, and 69·2% of ‘total digestible nutrients’. The present feeding trial has demonstrated that the figure for ‘total digestible nutrients’ obtained from the results of the pig digestion trial is a true measure of the productive value of the fodder cellulose for growth and fattening in bacon pigs, provided that the product is fed in a finely divided condition and in intimate admixture with the meal forming the rest of the ration.

1. Meiosis was studied in pollen mother cells of the following F1 hybrids: Victory × Avoine d’hiver, Victory × Grey Winter, Argentine × Avoine d’hiver, Victory × Argentine and Avoine d’hiver × Grey Winter.

The wool production of a small flock of Romney Sheep has been studied for a few years. When the sheep were 1 month old squares were tattooed on to four regions of each sheep.

The weight of wool from, and the area of, these squares has been studied.

We find that, under good growing conditions, for the same region, all sheep produce the same weight of wool per sq.cm. of skin per day (denoted by c), which is independent of age, seasons, year of birth of sheep, but varies from region to region, being higher the nearer the region to the mid-dorsal line.

When conditions are unfavourable the weight of wool a particular sheep produces from a particular region falls below the c value for the region, approximately, by a factor (1 – B/E), where E is the skin expansion ratio of the particular region and B is a number, the same for all sheep and all regions in one season and is greater the worse the season.

I am particularly indebted to Dr Hammond, School of Agriculture, Cambridge, and to Mr W. S. Kelly (Australia) for help and advice, and to the Animal Research Station, Cambridge, for providing the facilities for working with sheep. I wish to express my indebtedness to my colleagues of the Biology Department of this Association who have assisted me in various ways, and to Dr Daniels for help with the statistical treatment of the data, and to Mr R. C. Palmer for criticism and help in preparing the results for publication. My thanks are due to Mr B. H. Wilsdon, Director of Research, for his encouragement, to the International Wool Secretariat for providing the sheep, and to the Council of the Wool Industries Research Association for permission to publish the results.

1. Polycarboxylic and hydroxycarboxylic acids as well as pyrophosphoric acid form complexes with manganic manganese which are soluble over a wide pH range.

2. It is suggested that such complex formation may be of importance in maintaining manganese in an available form in soils.

1. In pony mares during oestrus in which a follicle was considered to be sufficiently ripe (thin walled) the intravenous injection of 500 i.u. pregnancy urine extract induced ovulation in nineteen out of twenty-three mares between 24 and 48 hr., in three cases within 24 hr., and in one case between the fourth and fifth days.

2. Dialysed egg yolk as a medium for storage of horse sperm for 24 hr. was shown to give satisfactory results when ovulation is controlled by the above method, so that it occurs within 24 hr. after insemination. Nine single inseminations during one oestrus resulted in five pregnancies.

3. The number of spermatozoa required for successful inseminations is discussed.

4. Means of detecting a sufficiently ripe follicle before injection with pregnancy urine extract are described.

5. It is shown that the duration of oestrus is shortened as the result of pregnancy urine injections.

6. Data is given concerning the time which elapses between ovulation and the cessation of oestrus.

Caecal coccidiosis of rather more than usual severity has been found to develop in chicks folded on a stemmy type perennial rye grass pasture at Hanns Hall Farm this season.

Subsequent brooder house experiments have demonstrated that chicks receiving a diet relatively low in protein and fibre content and relatively high in starch content, as cereals, failed to develop coccidiosis when subjected to severe infestation by coccidial oocysts, while the chicks in the same brooder house on a diet containing more roughage developed acute coccidiosis, and other chicks in the same brooder house on a diet containing a relatively high proportion of protein developed chronic coccidiosis.

As these experiments have shown that coccidiosis occurs on diets designed to promote proliferation of anaerobic bacteria in the intestines, and, conversely, does not occur when chicks are fed a diet designed to depress the proliferation of undesirable bacteria in the intestines, it would appear that coccidiosis in chicks is a secondary complaint, the primary aetiological agents being bacteria which proliferate to excess in the presence of roughage or protein.

Attention is drawn to the occurrence of postcoccidial abscesses which may occur after apparent successful treatment with Sulphamezathine for the cure of coccidiosis.

1. Lactation was studied quantitatively in a heterogeneous stock of laboratory mice, in order to find out whether the milk production of mice could be satisfactorily evaluated from measurements of the growth of the young; and, if individual differences were proved to be readily detectable, to find out to what extent these differences were heritable.

2. The total weight of the litter suckled, at 12 days of age, was found to provide a convenient measure of milk production.

3. Since the amount of milk given by a mouse is greatly influenced by the number of young suckled, allowance for differences of litter size was made by means of an index of performance which expressed the amount of milk given by a mouse at a particular lactation as a percentage of the average amount given to litters of that size. The index of performance thus evaluated the response of the mouse to a standard stimulus and gave no indication of the maximum productivity of the mouse.

The apparatus is a simplification and an improvement on one devised by the author for the study of soil metabolism (Lees & Quastel, 1944) Its function is to percolate a column of sieved soil automatically and regularly with small quantities of a well-aerated solution of metabolites and to return the percolated solution, now modified by the activities of the soil microflora, to the reservoir whence it came As this circulatory process is continuous, metabolic activities in the soil are reflected as chemical changes in the reservoir solution and can be followed by analyses of it.