In the scheme of analysis of plant extracts described in a former paper (Davis and Daish, J. Agric. Sci., 1913, 5, 437), before it is possible to calculate the proportion of dextrose and laevulose an allowance must be made for the pentoses present; it therefore became necessary to ascertain the exact value of the cupric reducing power of these sugars under the standard conditions adopted—namely those defined by Brown, Morris and Millar. Value s of the cupric reducing power of xylose have been given already by Stone, Weiser and Zeitschek, and of arabinose by the latter workers and by Ost; but as they were obtained under conditions different from those specified by Brown, Morris and Millar, they are unsuitable for the present purpose, and it became necessary to make a fresh series of determinations. Xylose and arabinose are the only pentoses which are at all readily obtainable and in the present paper attention is limited to these.

After a consideration of the ways in which the fertility of domestic animals is controlled some of the factors which limit it have been investigated. Various circumstances control the number of ova shed at each heat period. Data are presented which show that the low fertility of young as compared with adult sows is due to the fact that not so many ova are shed at each period.

Counts have been made of the number of corpora lutea present in the ovaries and number of foetuses present in the uteri of pregnant rabbits and pigs. The results show that many more ova are shed at the heat period than young are produced at birth. Some ova possibly may be lost but many after fertilization atrophy at some period of their development and undergo absorption in utero.

While the occurrence of atrophic foetuses only causes reduced fertility in animals which have many young at birth yet their occurrence in animals producing only one young would give rise to sterility so that the problem of the cause of the atrophy becomes an important one.

Investigation points to the conclusion that the atrophy is not bacterial in origin since frequently healthy and atrophic foetuses lie side by side in the uterus. Moreover no bacteria could be found either in the foetus or foetal membranes.

Evidence is given to show that nutrition cannot be the cause of the atrophy although it may affect to a certain extent the size of the young.

No conclusion has yet been arrived at as to the cause of the atrophy, and the several possibilities suggested are still under investigation.

Solutions were made by extracting the soils from certain of the Rothamsted plots on which wheat and barley had been grown for 60 years and upwards. Wheat and barley were grown in these solutions, which were renewed fortnightly. The comparative growth in the solutions was closely parallel to the growth of the crop on the plots in the field and corresponded to the composition of the solutions. The composition of the solutions as regards phosphoric acid and potash corresponded to the past manurial treatment of the soils and to the amount of phosphoric acid and potash they now show on analysis. Growth in the soil solutions agreed with the growth in artificial culture solutions containing equivalent amounts of phosphoric acid and potash. Growth in the soil solutions from imperfectly manured plots was brought up to the level of that in the solutions from completely manured plots on making up their deficiencies in phosphoric acid and potash by the addition of suitable salts. The phosphoric acid and potash content of the soil solutions was of the same order as the phosphoric acid and potash content of the natural drainage water from the same plots.

Wheat grew as well as barley in the solutions of the wheat soils, and vice versâ. In a similar set of solutions from the same soils the growth of buckwheat, white lupins and sunflowers corresponded with that of wheat and barley. Boiling effected no alteration in the nutritive value of the soil solutions.

In nutritive solutions of various degrees of dilution the growth of plants varied directly, but not proportionally, with the concentration of the solution, though the total plant food present in the solution was in excess of the requirements of the plant. When the nutrient solution was diffused as a film over sand or soil particles, as in nature, there was no retardation of growth due to the slowness of the diffusion of the nutrients to the points in the liquid film which had been exhausted by contact with the roots. Growth in such nutrient solutions forming a film over sand particles was much superior to the growth in a water culture of equal concentration, but the growth in the water culture was similarly increased if a continuous current of air was kept passing through it.

Caustic lime is found to have two distinct effects on the soil:

1. A partial sterilisation effect,

2. A chemical action, decomposing some of the soil organic matter.

The amount of caustic lime necessary to induce specific changes in the flora and fauna of the soil depends very largely on the character of the soil. The light sandy Millbrook soil, poor in organic matter and in carbonate, reacted sharply with 0·2 to 0·3 per cent. caustic lime; the Rothamsted clay soil, poor in organic matter but rich in carbonate, was found to react to 0·3 to 0·4 per cent.; the acid Woburn soil required an amount between 0·5 and 1·0 per cent., as did also the rich Chelsea garden soil, which already contained carbonate; the Craibstone soil, with a high organic and a low carbonate content, failed to react even to applications of 1·0 per cent, caustic lime.

With the extension of soil survey work and an increasing recognition of the importance, from chemical, physical and biological considerations, of the presence of calcium carbonate in the soil, it has become necessary to be able to determine accurately and with comparative ease the amount of carbonate in any given soil. During the past few years the methods adopted for this purpose have varied considerably, partly on account of inaccuracies which were only too apparent in comparative work, and also because of the need for greater convenience in manipulation.

A Considerable area of pasture land in Mid-Somerset, known locally as “teart” land, and also a smaller area in Warwickshire, cause scouring in cattle at certain times of the year. These pastures are a source of loss to the farmers and, from time to time, have been the subject of investigation. In 1862 the late Dr J. A. Voelcker published a valuable report on the subject, and in the main the observations and results discussed in the present paper are consistent with the suggestions which he put forward. Details of more recent work are to be found in various reports in the Journal of the Bath and West Society from 1895 to 1904.

1. It is shown that the strength of the discharge from an overhead wire network at a high potential is a variable quantity depending on the mobility of the carriers of the electricity and on the velocity of the wind. Attention has been drawn to the presence of radio-active disintegration products which may possibly be a complicating factor in the effect of the discharge upon plant growth.

2. The maximum current density of the discharge in some experimental stations, where the apparatus is constructed after the pattern of the Agricultural Electric Discharge Co., is of the order 10–11amp./cm.2

3. Measurements of potential gradient and of current density agree in showing that the effect of the discharge is not limited to the area under the wires. This is of importance as control and electrified areas have usually been placed close together in field experiments. Some account is given of the distribution of the discharge under various weather conditions.

4. Methods are discussed by which the control area may perhaps be kept under more normal electrical conditions in spite of the proximity of the overhead discharge wires. The results of some of the tentative efforts in this direction which were made at Dumfries during 1913 are briefly discussed.

(1) The method of taking four sub-samples and making in all 160 measurements of these sub-samples gives a satisfactory value for the average diameter of the sample.

(2) The average of the samples from each shoulder gives a good indication of the shoulder for each sheep.

(3) In comparing two sheep A and B we may take as almost certainly significant a difference between their two average shoulder diameters such that the ratio

that is a difference of some 8% of the average shoulder diameter of either of them for measurements taken as here indicated.

The present paper is written with no pretence at finality, and consequently some excuse is due for its publication at the present time. The author was induced to write it since the results so far obtained by him do not seem to agree, in all points, with the work previously done on the subject, and tend to show that there is much scope for future work both on this matter and also on a matter of much greater general importance, namely, on the influence of external conditions on a quantitative character.