1. Previous investigations showed that certain Scottish soils were of glacial drift origin, that they were comparatively rich in unweathered silicates and therefore in reserves of plant-food, that they showed considerable variation in such silicates and were capable of classification accordingly. Some indication was also shown that the glacial drift, and hence the resulting soil, was sometimes of local origin, its character being determined by the underlying rock. In the present investigation a more extensive survey of Scottish soils has been made in order to discover to what extent these preliminary findings might be applicable generally.

2. For this purpose soils have been collected from various localities in the north, north-east, west and south of Scotland, and have been analysed mechanically and the “fine sand” fraction examined mineralogically.

With the aid of a careful technique a critical investigation has been made of the Hygroscopic Coefficient of soil at five temperatures, ranging from 15° C. to 35·6° C. It has been shown that (1) the customary 12–24 hours' period used by previous workers is much too short to give any approach to final values; (2) at the lower temperatures all except very light soils continue to take up water almost indefinitely, and it is not possible to extrapolate to an approximate final value; (3) these final values decrease with increasing temperature but in the early stages the rate of moisture absorption increases with increasing temperature; (4) the disputes as to whether the Hygroscopic Coefficient increased or decreased with temperature were due to the unrecognised operation of the effects detailed in (1) and (3) above.

1. Of 583 pig foetuses of all ages, 331 were found to be males and 252 females, giving a male percentage of 56·8, which is much higher than the approximate equality between the sexes that seems to exist at birth. This result confirms Jewell, who found a male percentage of 55 among 1000 cow foetuses.

2. These 583 pig foetuses when classified by weight (0–100 gm., 101–300 gm., 301+gm.) gave the following percentages of males for the respective groups, 59·1, 57·0, 53·2. In other words, the percentage of males decreases as gestation proceeds, a result which can only be brought about by a differential mortality of males and females. It would appear that the percentage at conception must be very near 60 per cent. or 150 males per 100 females.

3. The sex-ratios of foetuses from the left and right cornua show no significant difference, 55·0 for the right and 54·7 for the left.

4. The males were found to average about 7 per cent. heavier than the females.

5. There seems to be an inverse correlation between the number of foetuses in a horn and their average weight. Foetuses from the left cornu have a slightly greater weight than those from the right, and this may be connected with the slightly inferior fertility of this horn.

6. The excess of males at conception is discussed in the light of the implications of the chromosome mechanism of sex determination, and reference is made to the greater mortality of the males.

In the course of an investigation on the nitrification process in soils a series of pot experiments was set up to compare the manurial actions of some typical organic nitrogen compounds. The laboratory work was interrupted at an early stage; the results of the pot experiments are briefly described in this note.

The removal of soluble humus by alkaline extraction from both a garden and a field soil reduced the productiveness over a series of crops in pot experiments. The field soil showed an initial but temporary increase in productiveness.

1. The reaction between lime sulphur and acid lead arsenate is shown to be small and to have little effect on the chemical properties of either material as a spray.

2. It is shown that the oxidation of lime sulphur proceeds according to the empirical formula:

CaS.Sx + 30 = CaS2O3 + Sx-1

and that the calcium sulphides are hydrolysed in aqueous solution.

3. The addition of lead arsenate has no effect on the amount of sulphur precipitated from the lime sulphur by oxidation or by the action of carbondioxide.

4. Lead arsenate is only slightly decomposed by lime sulphur or by the oxidation products of lime sulphur, the main decomposition being due to the action of sulphuretted hydrogen formed by the hydrolysis of the calcium sulphides. This decomposition becomes marked in the presence of carbon dioxide which reacts on the calcium sulphide to form sulphuretted hydrogen.

5. The fungicidal value of the mixed spray—as judged by the mildew killing properties of the polysulphides—is not less than that of lime sulphur alone. Additional fungicidal properties may be expected from the presence in the spray of soluble arsenates and thioarsenates.

6. Judging by the chemical changes which take place in the mixed spray the insecticidal value of the lead arsenate would not appear to be greatly affected by the addition of lime sulphur.

7. There is an increased amount of soluble arsenic formed by the action of carbon dioxide on the mixed spray which may prove sufficient in amount to cause spray injury.

8. The A.O.A.C. method for the determination of sulphate sulphur in lime sulphur solutions is shown to be inaccurate. A method yielding more concordant results is proposed.

An account has been given of a digestion trial with sheep which was designed to assess the nutritive value of “sweet” rye grass and clover stack silage. The most noteworthy feature of the results was the appreciable depression of digestibility suffered by the crude protein of the crop as a result of ensilage. A tentative explanation of this effect has been put forward, based on a consideration of the high temperature attained in the stack.

In conclusion, the writer would like to state that the silage was made under the direction of his colleague, Arthur Amos, Esq., M.A., and to him thanks are due for permission to use the fodder for the purposes of the feeding trial. The writer also tenders his thanks to Mr G. Thurlbourn for considerable assistance in connection with the analytical work and the care of the animals.

(1) Removal of chlorine ions by soil from dilute hydrochloric acid solution has been shown to take place under the experimental conditions employed.

(2) Interaction between dilute acids and soil (free from carbonates) has been studied. The results show that hydrochloric acid, nitric acid, sulphuric acid, acetic acid, citric acid and phosphoric acid all react with soil. The state of equilibrium between the soil and the acid solution can be satisfactorily expressed by Freundlich's equation. The order of reactivity of the soil towards various acids does not follow any obvious rule.

(3) The various soil fractions do not show any fundamental difference in their equilibrium relationship with regard to an acid solution; the order of their power to react with acid following inversely the order of the size of particles in them.

(4) The experiments recorded seem to support the view that the interaction between soil and acids is a surface phenomenon.

A résumé of the analytical methods hitherto employed for the chemical investigation of samples of silage has been given. It has been shown that these methods fail to yield trustworthy results when applied to the analysis of “sour” silage, owing to the disturbing effect of the presence of appreciable amounts of ammonium salts of organic acids in this type of silage.

Investigations have been made into the behaviour of the ammonium salts of acetic, butyric and lactic acids, when solutions of these substances, in the presence and absence of the free organic acids, are (1) submitted to distillation in steam, (2) evaporated in the steam oven under conditions comparable with those obtaining during the determination of the dry matter of silage. The bearing of these results on the problem of silage analysis has been discussed.

A modified analytical procedure for silage investigations has been devised which is capable of general application.

Part I. The changes in amount and composition of the mammary secretions of a heifer in its first pregnancy are recorded.

The most striking feature is the abrupt appearance at half-way through pregnancy of a viscous secretion consisting largely of globulin.

These results are extended to the primiparous and to the multiparous “dry” goat.

Colostrum is shown to be normal milk admixed with the globulin secretion.

The significance of the globulin is discussed. Reasons are advanced indicating that it may be an excretion of the cell when it changes from the growth phase to the secretory phase of life.

The stimulus to mammary growth is briefly discussed.

A partial analysis is given of the secretion from the tubercular udder of a cow. This secretion resembles somewhat the secretions of mid-pregnancy.

Part II. Instances are given of cases of premature lactation in the goat, and analyses are recorded of these secretions.

These cases are discussed in the light of Part I of this paper, and their bearing on the corpus luteum theory of mammary development is considered. The sexual precocity of the goat is such that the mammary growth may in all cases have been due to luteal influences.

A few cases of premature lactation in the cow are also reported.

The theory that the foetus produces a hormone inhibiting lactation is shown to be unnecessary.

An account is given of a reliable technique that has been evolved for making dynamometer measurements in the field. It has been shown that quite small variations in the trace of the drawbar pull are significant, and correspond to actual variations in the resistance of the soil. No significant change in drawbar pull is produced by imperfect adjustments in the hitch or set of the implement within the limits met with in ordinary ploughing, except in so far as the depth of working is affected. The drawbar pull bears a linear relationship to ploughing depth within the region of ordinary ploughing. The slope of the land is without appreciable effect on the drawbar pull up to gradients of 1 in 40.

Measurements are recorded of soil resistance to ploughing, taken with a view to testing the uniformity of a soil over a single field. The results have been examined for significance and indicate large variations over short distances. The differences have been represented by means of isodyne contours (i.e. lines of equal drawbar pull), drawn on a map.

The importance is emphasised of assuming and allowing for such variations before drawing conclusions from the drawbar pull recorded by different implements.

Preliminary work is described showing that the variations are correlated with clay content and also with the growth of a crop in its early stages.

Maps of soil resistance to ploughing have been drawn up from the dynamometer readings over several seasons for the Rothamsted classical plots, carrying wheat, barley and roots respectively.

The conclusions as to the effect of manurial treatment are only of a general nature at the present stage of the work. Such differences are certainly small in comparison with the natural variations in the soil.

In the case of the Broadbalk wheat plots the drawbar pull values have been shown to have a close relationship with the clay content of the soil and with certain aspects of the soil drainage.