1. Following an examination of weaning weight with respect to litter size, it is concluded that no general relation between the two exists. Although a significant regression of weight on litter size was found, it appears probable that in herds where the relation between fertility and milk yield is different, such a regression will not necessarily be found.

2. A sampling experiment was carried out to determine the extent to which a sample might be expected to represent the whole litter. A correlation of 0·96 was found between the mean growth rate of samples consisting of the four pigs nearest the average at weaning and the mean of the whole litter. This represents a loss of 8 per cent of the information. With three or two pigs chosen in the same way the loss was greater. Samples of four pigs chosen at random did not give results significantly different from those of the four pigs nearest the average. The choice of the heaviest four pigs resulted in a loss of 15 per cent of the information.

3. The slight difference between the results from the random sample and the sample of the four average pigs indicated that there must have been only a small correlation, between weaning weight and subsequent rate of growth. An analysis of post-weaning rate of growth showed that the intra-class correlation of pigs of the same weaning weight was 0·15. Individual weight at weaning would therefore appear to be of slight value in estimating subsequent performance.

4. Intra-litter correlations of growth rate for litter classes eight and nine were found to be 0·3 and 0·5. These values are higher than those found by others, probably as a result of the inclusion of the pre-weaning period in the calculation of the growth rates. There would appear to be grounds for believing that at least a fifth of the individual variance may be accounted for by additive gene effects.

1. The total yield of dry matter of rye-grass, grown in the presence of inoculated (a) peas, (b) red clover, (c) serradella, in sand with no added nitrogen, after 13 weeks' growth was increased by about three times in the peas-rye-grass series, twice in the clover-rye grass series, and nearly twice in the serradella series in comparison with the yield of rye-grass grown alone.

2. The nitrogen percentage and total nitrogen yield of rye-grass were greatly influenced by associated growth with peas, clover or serradella. Rye grass grown with peas after 13 weeks' growth contained nearly five times, grown with clover three times, grown with serradella about twice, as much total nitrogen, as grass of the same age similarly grown, but in the absence of leguminous plants.

3. Among the three leguminous species tested at Pulawy, peas were the best companions for rye-grass, giving the highest amount of assimilated nitrogen, while serradella gave the smallest.

4. In another experiment, when barley and (a) peas, (b) red clover, (c) lucerne were grown together in sand without added nitrogen, only peas exerted a beneficial influence upon the yield of dry matter and the nitrogen percentage and total nitrogen yield of barley.

1. Experiments were carried out in four seasons at Barberton, South Africa, occupying approximately 2¼ acres of ground. Three soil treatments were used, viz. Normal (N), Compressed (C) and Grubbed (loosened) (G).

2. Measures of consolidation of the soil were made with a specially designed apparatus, and large differences established (pp. 516–520).

3. Estimations of water content and nitrate content were carried out. No great differences were found (pp. 520–524).

4. Fortnightly samples of the plants were taken, from which numerical data were collected designed to estimate morphological development (primary data, pp. 526–529).

5. Derived data on net assimilation rate, relative leaf-growth rate and efficiency index were calculated (pp. 529–533).

6. Growth in total dry weight was found to conform approximately with an exponential law up to the time of flowering. Up to this stage also net assimilation rate was found to remain constant.

7. Growth differences between treatments were related to variation in net assimilation rate only (p. 531).

8. The results were analysed statistically. Significant results alone are emphasized.

9. In all respects growth and development on the consolidated soil was more rapid than that on the grubbed soil, normal being generally intermediate.

10. The results are discussed with reference to the question of nitrogen supply, water supply and aeration of the soil.

1. A preliminary account is given of experiments on the compressibility of soils in field condition, and two methods for obtaining compressibility curves, one for the field and one for the laboratory are described. The laboratory apparatus automatically draws a curve relating deformation to the square root of the load built up.

2. The theoretical relationship between load and deformation is discussed, the conclusions reached being at this stage semi-quantitative.

3. Laboratory compression curves are shown to indicate the characteristics of soils in various states of tilth, and the effects of drainage condition, frost action, etc. are discussed.

4. Such factors as size of soil crumb, depth of layer tested, and moisture content of soil samples for laboratory studies are considered.

5. Preliminary field experiments are described in which the effect of simple cultivation processes on soil compressibility were measured.

6. Tentative conclusions about the significance of the differences in the shape of the laboratory curves are given, though these may need to be modified, and will certainly be extended following further experimentation.

1. The conditions governing base exchange equilibria in soil profiles are discussed.

2. Exchangeable cation contents of six profiles are reported, the results including figures for Ca, Sr, Mg, Na, K, H and exchange capacity, as well as clay content and pH value.

3. It is shown that cation displacement occurs as a result of the downward movement of hydrogen ions from the surface layers, and a layer of minimal basic cation content exists at about 30 cm. depth.

4. Below this depth the basic cation content increases once again, but the base exchange capacity follows the clay content fairly closely.

5. Calcium and strontium are displaced (and readsorbed) at similar rates, in accordance with their exchange constants, although there is about 400 times as much calcium as strontium present. The behaviour of the other cations also appears to be in accordance with theoretical demands.

An investigation has been made, by the method of balance trials, of the utilization of food protein, at different levels of protein intake, by bacon pigs throughout the period of growth from weaning to slaughter. Information has also been secured relating to the retention of lime, phosphoric acid and chlorine. The main conclusions are as follows:

(1) The young pigs after weaning were able to digest their food with as high an efficiency as was displayed in the later stages of growth. The extra protein in the high-protein rations had little or no effect on the extent to which the food was digested.

(2) No evidence was secured at any stage of the trials suggesting the presence of protein in the urine of the pigs subsisting on the high-protein diet.

(3) The gilts showed a consistently higher rate of nitrogen retention than their brother-hogs. This behaviour was manifested even when the protein supply in the gilt's ration was lower than that in the ration of the hog with which it was compared. This more efficient utilization of food protein by the gilts is held to explain the tendency of gilts to give somewhat leaner carcasses than hogs.

(4) Nitrogen retention from the high-protein diet was no higher than from the normal-protein diet, a rinding suggesting that the amount of protein in the normal rations is sufficient to meet the demands for the quick growth required by modern standards of bacon production.

The associated growth of peas and different non-legumes (barley, oats, wheat, and potato) was investigated both under sterile conditions and in ordinary pot cultures. In the former case the medium consisted of quartz sand, and in the latter of clay or sandy loam soil, poor in soluble nitrogen. It is shown that nitrogen was transferred from the pea nodules to the non-legumes.

In sterile cultures, where the excreted amino-acids cannot undergo decomposition, oats, wheat and barley utilized only a part of the excreted nitrogen, generally less than 50 per cent. In some instances, however, the barley took up considerably over 50 per cent of the excreted nitrogen. There was an apparent accumulation of aspartic acid in the medium of the associated cultures. In pot cultures, where the amino-acids may have been broken down by contaminating micro-organisms, the transfer of the excreted nitrogen to the potato exceeded 90 per cent.

All experiments show that with increasing ratio of non-legumes to legumes the growth of the peas suffers, obviously from lack of nitrogen. Under these conditions, the excretion from the nodules increases to such an extent that the peas receive only a small fraction of the nitrogen fixed by the nodules. The major part of the carbohydrate material furnished by the pea for the amino-acid synthesis in the nodules is excreted into the medium. This naturally causes disturbances in the growth of the pea.

1. Large White sows are more prolific than Large Black sows, but mortality up to 6 weeks is higher in the former breed. At 6 weeks, litters from both breeds contain practically the same number of pigs. At that age, however, pure-bred Large White pigs appear to be slightly heavier than those of the Large White/Large Black cross.

2. Sows show no significant deterioration in litter size or in litter weight at 6 weeks up to the tenth litter, but percentage death-rate tends to increase with farrow number.

3. There appears to be little advantage in producing litters with more than 12 pigs at birth. In litters containing more than 12 pigs the addition in number is more than off-set by an increase in death-rate.

4. There is no significant difference at 6 weeks between the average weights of pigs from litters of different size at birth. There is, however, a difference in average weight according to the number of pigs surviving at 6 weeks; the larger the number the lighter the pigs.

5. The season in which the sow farrows appears to exercise a considerable influence on survival rate at 6 weeks; approximately one pig more per litter surviving in the summer than in the winter months.

6. There is a definite negative correlation between the weight of the pigs at 6 weeks and the age at which they reach bacon weight. But the rate of post-weaning growth of the heavy pig is not necessarily greater than that of the light pig.

7. Post-weaning mortality appears to increase with increase in litter variation.

8. Litters which are fattened during winter months take longer to reach bacon weight than those fattened during summer.

9. Rapid growth rate and high grading results are not incompatible when the conditions of suitable rations, good stock, and proper management are observed.

10. The third and fourth week of age appears to be a critical stage in the life of the suckling pig, and especial care must be exercised in its treatment at that period.

The present paper records some investigations on the growth of the clover- and pea-nodule organisms (Rhizobium trifolii Dangeard and Rh. leguminosarum Frank), and the nitrogen fixation of the pea, at low temperatures. Growth of the bacteria was studied with pure culture experiments in large flasks, in which the bacteria were grown on a solid gelatine medium. The amount of nitrogen in the bacterial mass thus obtained was used as the basis of comparison. The fixation of nitrogen by peas was studied with a pot-culture experiment in a relatively cold greenhouse. Inoculated plants were grown in quartz sand, and were supplied at an early stage with mineral nitrogen either as Ca(NO3)2 or (NH4)2SO4. The plants were harvested after flowering and analysed. The main results of these experiments were the following:

(1) Pure-culture experiments with five strains of clover-nodule bacteria and four strains of pea-nodule bacteria showed that at 6–13° C. the strains imported from more temperate climates grew distinctly less well than did the northern European strains. Even between the Swedish and Finnish strains there were clear differences: the latter formed the more bacterial matter in the cold. It may be appropriate to consider such differences when selecting cultures for inoculating leguminous crops.

(2) In the pot-culture experiment, the application of mineral nitrogen (30 mg. N per plant) to inoculated peas kept at relatively low temperatures had very little effect on the amount of dry matter produced. The slightness of this effect was similar to what has been previously observed in experiments at more favourable temperatures. Nitrogenous fertilization slightly lowered the amounts and percentages of total N present as protein and amino nitrogen, in the crop; but nitrate application somewhat increased the nitrate content of the crop. Hence, it may be concluded that, even under these low-temperature conditions, the application of artificial nitrogen has not had a favourable effect on the size or quality of the crop.

The water consumption was determined of thirty-seven Large White suckling sows that were tethered on grass. The mean consumption was 43 lb. a day, the variation between sows, and of particular sows from day to day, being particularly wide. The consumption was practically unaffected by weather and was nearly the same in summer and winter; it was impossible to demonstrate any relation between consumption and number or weight of litter, but there was evidence of a slight decrease as lactation progressed.

It is evident from a brief discussion that exact balance experiments as to the partitions of water for its various uses in the body of the pig are badly needed. It is hoped that the facts given here may draw attention to this point which has been neglected in animal nutrition studies.