I. As a result of withholding food for a few days, together with an injection of phloridzin, thereby reducing the nutrition, the daily yield of milk in goats was diminished and in one case the flow was actually stopped. On giving food again the yield returned almost to normal within a few days.

II. As the daily yield of milk diminished under these conditions so the percentage of fat in the milk rose. Limitation of the available nutriment in the body (change from a high to low state of nutrition) did not reduce the percentage of lactose or protein in the milk (Paton and Cathcart) but reduced the quantity of milk (together with the amounts of protein, sugar and salts) produced. The secretion of fat was not at first affected by the change in metabolism and as a consequence milk rich in fat was produced.

III. The amount of fat secreted per day under these conditions of diminishing yield was however not constant but became reduced, possibly as a secondary effect of the decreased secretion taking place in the gland cells.

IV. On again giving food to animals in such a reduced state of nutrition, the percentage of fat in the milk decreased as the yield increased, in some cases to such an extent that it was below that of the normal milk before the experiment began.

The results of these investigations show

1. The substances sold as “Phosphate of lime” and “Calcium Phosphas B.P.” are not pure tricalcic phosphate but are mixtures of di- and tricalcic phosphates.

2. Sodium phosphate (Na2HPO4) added to ammoniacal calcium chloride and the resulting precipitate washed with water yields a mixture of di- and tricalcic phosphate and calcium hydrate.

3. Bone ash dissolved in hydrochloric acid and precipitated with ammonia, the precipitate being well washed, yields also a mixture of di- and tricalcium phosphate and calcium hydrate.

4. When three equivalents of lime (3CaO) are made to act on one equivalent of phosphoric acid (P2O5) and the resulting precipitate removed with little delay pure tricalcium phosphate is obtained.

The detailed examination of humus soils of various kinds is becoming of increasing importance in view of the schemes now on foot for the reclamation of much heath and moor land. One of the most important things to establish has seemed to the authors to be the amount of nitrogen existing in the form of ammonia or of ammonium compounds, as it is possible that a knowledge of this figure might form a basis for a more scientific classification of soil organic matter than at present exists.

One of the difficulties which hinder the extended use of the nut-oil-cakes (palm kernel, coconut and ground-nut) is the prevalent impression that these cakes deteriorate rapidly on keeping. In recent articles dealing with these cakes frequent reference has been made to this point. Thus Voelcker (9) in his Annual Report for 1914 states that “one inconvenience attaching to palm-nut and coconut cakes is that they do not keep as well as linseed and cotton cakes and that there is a tendency for them to turn rancid.” In his Report for 1915, however, he says, “I have come across but few instances either with palm-nut cake or meal, in which these have been rancid or not in good condition.” Murray (8) states that manufacturers should realise that they still have to reassure farmers regarding the keeping qualities of palm kernel cake. In a later article in the Journal of the Board of Agriculture (3) it is stated that “palm-nut kernel cakes in the past have had the reputation of soon going rancid…. At the present day, before the kernels are crushed they are subjected to a process of cooking, by which the ferment that causes the oil to turn rancid is rendered inactive.” The validity of this latter assertion seems doubtful in the light of the recent work of Calder (2) which shows that the lipase, present in the resting seed in the form of its zymogen, is not destroyed during the manufacture of the cake, the mass of crushed kernels not being sufficiently heated in every part prior to pressing to secure this object completely. Similar statements have been made as to the liability of coconut and ground-nut cakes to become rancid on storing (3,4).

In the course of a general study of the chemical changes taking place in the manure heap, a number of experiments were made with the object of determining the loss of nitrogen during the aerobic fermentation of urine, straw and faeces, both separately and in various combinations. In the very first experiment with faeces, however, instead of finding a loss of nitrogen, appreciable gains were recorded, and this opened the enquiry which forms the subject of the present paper. In all the experiments a current of washed air was drawn for several hours daily through the flasks containing the substance under examination, any ammonia volatilized being retained by N/10 sulphuric acid. At the end of the experiment the total nitrogen left in the fermented substance, added to any nitrogen recovered in the wash flasks, was compared with the original total nitrogen.

It is now generally recognized that the glands of internal secretion play an important part in regulating metabolism and so controlling the nutrition of the animal. Hatui found that castration was followed by a putting on of fat except in those cases in which the pituitary underwent a compensatory hypertrophy, when the animal remained normal in weight.

Gill in 1871 first pointed out that when an excess of basic lead acetate is added to a solution of invert sugar the negative rotation of the latter is greatly reduced owing to the formation of a soluble lead compound of laevulose. If sufficient lead solution is added the negative rotation may become a positive one; thus in one experiment quoted by Gill a negative reading of – 28° was transformed into a positive value of + 57°. The change of rotation was not, however, permanent and on removing the lead or on acidifying the solution the original rotatory power was restored. The change of rotation was attributed to an effect of the lead on the laevulose only; a solution of dextrose was practically unaffected by the presence of basic lead acetate. Since Gill's paper the effect of basic lead acetate as a source of error in sugar analysis has been the subject of numerous papers especially by Pellet, Svoboda, Edson, Prinsen Geerligs, Watts and Tempany and Eynon.

The interest aroused recently in the utilisation as feeding-stuffs of the residual cake or meal remaining from the extraction of oil from palm kernels has directed attention to the scantiness of our information as to the digestibility of these products. The average digestion-coefficients given in the commonly-used tables of Kellner are based in each case upon only three experiments with two different consignments of material, and showing in certain particulars a very wide range of variation in the individual results. With one exception, where an ox was used, these experiments were carried out with sheep and all date from the ’seventies of last century (1, 2).

The present work has been undertaken with the object of ascertaining the actual compounds of phosphoric acid and lime present in rock phosphates, a better knowledge of these compounds being of some agricultural importance.

At the close of the digestion experiments described in the foregoing communication a quantity of the “seeds” hay of known composition and digestibility remained which was sufficient for one further experimental period. The opportunity was therefore taken of determining the digestibility of dried yeast, a by-product of the fermentation industries which is being produced in increasing quantities and which has attracted notice since the outbreak of war.

1. The Hutchinson-MacLennan method for determining the lime requirements of soils, when practised under suitable standard conditions, gives more reliable indications than are obtainable by the ordinary methods of chemical analysis.

2. The method gives indications which appear to be uniformly in excess of the actual requirement of the soil for lime as judged by economic standards: hence a correcting value seems advisable.

3. The correcting value for the soils of Canterbury Plains is about 0·10%.

4. The greater acidity and higher lime requirement of soils of the Southland Plains appears to be due to a combination of lack of natural under-drainage and high rainfall, which prevents aeration and oxidation of organic matter, so that “sour” humus accumulates in the soil.

1. By determination of the internal pore space in blocks of soils and comparison with the observed value for the linear shrinkage it is found that a linear relationship appears to exist between the two values.

2. By extrapolating the curve thus obtained an approximation for the limiting value of the shrinkage in the case of pure colloidal clay is arrived at amounting to approximately 23 per cent.

3. On this assumption it becomes possible to calculate the approximate content of colloidal material in any soil from a knowledge of the linear shrinkage.

4. Results are adduced, showing the values obtained for the shrinkage in the case of separated fine silt and clay fractions in the case of two soils of known shrinkage and physical composition, and compared with the values calculated from previous assumptions.

5. The results of the calculation of the content of colloidal clay in the foregoing manner in the case of 16 Leeward Islands soils are appended.

The experiment described in the present communication was carried out at the Manor Farm, Garforth, during the summer of 1916, with the object of obtaining information as to the nature of any changes in the composition of milk-fat that might be effected by the feeding of palm kernel cake to cows.

(1) Grassland has been classified as natural and semi-natural; both classes have been further sub-divided according to the botanical composition of the herbage in relation to habitat (pp. 27–36).

(2) The plants which colonise natural grasslands have been called primary indigenous species; and those which come in without being sown and contribute largely to the herbage on semi-natural types have been designated secondary indigenous species (p. 37).

[The following is an account of experiments carried out by the author during the year 1913–14 in collaboration with Professor S. J. M. Auld, D.Sc., Ph.D., F.I.C., etc., of University College, Reading. Dr Auld is now engaged in military duties and the task of presenting this report therefore devolves upon the author who wishes it to be clearly understood that Professor Auld must not be held responsible for any inaccuracies or other faults.]

From the agricultural point of view the amount of oxygen carried into the soil as gas dissolved in rain has considerable interest. Since all the oxygen required either for the bacterial activities of the soil or for the root aeration of growing crops must first pass into the dissolved state, the supply of this essential element in a form immediately available must exercise a proportionately beneficial effect on the manufacture of plant food or on the growing crop. Recent work on the decomposition of organic matter in the soil has shown that rainfall is one of the chief factors controlling bacterial activity, but that its influence is due to something more than the supply of water. The oxygen dissolved in the rain appears to be the missing factor. As very little systematic work seems to have been done in this direction, estimations of dissolved oxygen in rain at Rothamsted were made from time to time during the year 1915.

The soils of North Wales have been studied by the writer during the past four and a half years in field and laboratory. A number of types have been recognised and studied. Further work is necessary to elucidate the properties of the types already identified and to establish fresh types. The purpose of the present paper is to give an account of the soils most typical of the area, namely the soils derived from material of the Pre-Cambrian, Cambrian, Ordovician and Silurian formations in the counties of Anglesey, Carnarvon and Denbigh. In this group are included soils derived from the weathering of local glacial drift, and the associated sandy, alluvial and peaty soils. The soils formed of newer materials, including later Palæozoic soils and Glacial drift of external origin may form the subject of a separate paper.

In certain seasons very severe losses are caused to the hop-crop by the depredations of the mildew Sphaerotheca Humuli (DC.) Burr. Among hop-growers in England this mildew is commonly spoken of as “mould” when it occurs on the leaves or the female inflorescences (“burr”) of the hop-plant, and as “red mould” when it attacks the stipular bracts and bracteoles of the strobiles (“hops”) (1).

Few reactions are more important to the soil chemist than that involved in the action of dilute acids on the phosphorus compounds of the soil, but, owing to its complex nature, little has been definitely ascertained about it. The importance of the reaction lies in the fact that it affords a distinction between those phosphorus compounds which are fairly easily soluble, and may therefore be expected to enter the plant root without much difficulty, and the less soluble compounds which are of less value in the nutrition of plants.

In the Agriculture Returns published by the Board of Agriculture, the figures for swedes and turnips are given together. Taking the figures for 1913, we find that swedes and turnips were grown on 1,757,000 acres of land in the United Kingdom, and that the total weight of crop obtained was 25,319,000 tons. No other green crop occupied so large an area, and no other crop of any kind produced as great a weight of fodder.