The ammoniacal nitrogen in the Rothamsted rainwater amounts on an average to 0·405 part per million, corresponding to 2·64 lb. per acre per annum. The yearly fluctuations in lbs. per acre follow the rainfall fairly closely. The monthly fluctuations also move in the same direction as the rain, but the general level is highest during May, June, July and August, and lowest during January, February, March and April (Tables 1, 2, 3, and Figs. 1 and 2).

The nitric nitrogen is on an average one-half the ammoniacal, viz., 1·33 Ib. per acre per annum. The amounts fluctuated year by year and month by month in the same way as the ammoniacal nitrogen and the rainfall until 1910, since when there has been no simple relationship (Tables 1, 2, 3, and Figs. 1 and 2).

Reasons are adduced for supposing that the ammonia arises from several sources. The sea, the soil, and city pollution may all contribute. Neither the sea nor city pollution seems able to account for all the phenomena: the soil is indicated as an important source by the fact that the ammonia content is high during periods of high biochemical activity in the soil, and low during periods of low biochemical activity.

The present paper contains the results of investigations on silver-leaf disease which are a continuation of those previously described by one of us (1,2) in earlier numbers of this periodical.

Some time ago it was thought desirable to duplicate as far as possible in different localities the experiments conducted on this disease. Hence most of the experiments described in this paper have been carried out both at Cambridge and at the John Innes Horticultural Institution, Merton.

The present investigation was undertaken to study the decomposition of cyanamide and dicyanodiamide in the soil and their specific action on plant growth. Their close chemical relationship necessitated a comparison of their respective behaviour in the soil. Dicyanodiamide is a polymer of cyanamide to which the formula C2H4N4 is assigned. Morrell and Burgen(1) and Werner (2) have shown that the polymerisation is caused by acids or alkalis, even in small amount, but a weak alkali is substantially more effective than a correspondingly weak acid; the rate of the change is greatly increased by raising the temperature. The process does not appear to be reversible.

The seeds of many species of plants have a habit of germinating in unexpected places under various conditions, and the question of the vitality of seeds is one that has frequently engaged the attention of scientists. It has often been claimed that seeds obtained from old pyramids and sepulchres have germinated when placed in favourable circumstances, but Becquerel states that strict enquiry and experiment show that authentic seeds of such origin will not germinate, but that the seeds so obtained which do germinate have proved to be frauds inserted by the fellaheen for the sake of gain. Various writers (quoted by Becquerel) have claimed the power of germination for seeds buried for very long periods. Michelet claimed that seeds of Galium anglicum, buried 3000 years ago in the valley of Doubs, had retained their power of growth; von Heldreich, that Glaucium Serpieri from land covered by excavated scoriae 1500 years ago, was still viable; much doubt, however, has been thrown on the authenticity of such seeds.

An attempt has been made to determine the intensity of the biological processes in the soil during the most important periods of the Egyptian farm rotation. The fluctuations of the nitrate content in the surface soil have been taken as the most important index of this activity.

In all cases the moisture content of the soil limited these processes more than any other factor.

There was observed throughout the season in a cotton field a relatively large amount of nitrate, more than sufficient for the immediate needs of the cotton plant. The lack of response on the part of the Egyptian cotton crop to nitrogenous fertilisers may be accounted for in part, if not entirely, by the fact that nitrification in the soil is well ahead of the needs of the crop.

Nitrification under wheat and maize shows in general the same characteristics in Egypt as in other parts of the world; there is no accumulation of nitrate in the soil.

The winter fallow, depending for its water on the rainfall, may be a period of steady nitrification when the amount of the rainfall is sufficiently high.

Stems of Dactylis glomerata were collected from grass-plots which had received different manurial treatment as regards potash.

The yield of hay from these plots was in close agreement with the average which shows that the season during which the work was done was not abnormal.

The thickness of the wall, the diameter of the lumina and the ratio of the lumen to the wall were measured both in sclerenchyma and metaxylem elements.

It was found that in the early stages the sclerenchyma walls were thinner where potash had been supplied, but that this effect was lost as the season progressed.

The lumina were larger in plants which had received potash, when nitrogenous fertilisers had not been added, but in the presence of ammonium salts, this effect was reversed.

In the xylem the thickness of the walls was unaltered whether potassic fertiliser were added or not. When no nitrogenous manures were added the diameter of the lumen was decreased in the presence of potash, but when ammonium salts had been applied, the diameter was increased by the application of potassic fertilisers.

With the great increase in the use of palm kernel cake, which has taken place in this country in the last few years, attention has been drawn to the rancidity which the cake is liable to develop under certain conditions. R. B. Calder (see this Journal, April, 1916, VII, 470) has shown that the cake develops rancidity under sterile conditions and concludes that the action is due to the presence of a lipase. Calder has taken as his criteria of rancidity a sour smell in some cases and an acid reaction with litmus in others. There is some confusion in the use of the terms “rancidity” and “ acidity.” Although rancidity stands in close relationship to acidity and invariably accompanies a high acidity in oils and oil cakes, the terms are not synonymous.

Nitrogen, one of the most important plant nutrients, is present in the soil mainly as organic compounds which, with certain exceptions, are not, in those forms, assimilable by ordinary cultivated plants. The organic compounds undergo a series of chemical changes before they are ultimately changed into nitrates which are practically the most useful compounds of nitrogen which can be taken up by plants.

1. The percentage of dry matter in the potato tuber is lowest in the skin and increases to the inner cortical layer, the zone containing the greater part of the vascular system, and decreases towards the centre of the tuber.

2. In each zone the proportion of dry matter is higher towards the umbilical than the terminal end of the tuber.

3. The percentage of nitrogen in the fresh material tends to decrease from the skin to the inner cortical layer and to increase in the medullary zone. Thus it increases from zone to zone in the opposite direction to the dry matter.

4. Nitrogen tends to increase with dry matter from the terminal to the umbilical end.

5. Microscopical examination shows the starch grains densest in the region of the vascular system, and decreasing towards the centre and surface of the tuber.

6. A high degree of correlation is found between the specific gravity and percentage dry matter of whole tubers.

7. For purposes of sampling the method of taking two radially opposed sectors, or two diagonally opposed eighths, was far more accurate than the coring method.

During the years 1908–1913 inquiries with reference to the infertility of soils were frequently received from farmers in various parts of Cardiganshire. Upon examination it was found that the primary cause of infertility in most of the cases was the presence in the soil of appreciable quantities of lead. At first it was thought that only a few isolated spots were thus affected. Further investigation, however, revealed the fact that a relatively large area of what should be naturally the best land of North Cardiganshire was suffering from the same cause, and that a considerable number of farmers were of opinion that both their soils and their live stock suffered from “lead poisoning.” Consequently, it was thought advisable to make a survey of the affected land and to investigate possible remedial measures.

The experimental results submitted in the preceding pages may be summarised as follows:

Seven English soils have been examined in order to ascertain the validity of Greig Smith’s claim that partial sterilisation effects may be due to the destruction of bacterio-toxins in the soil. The results obtained with six of these soils show that:

1. The untreated extracts of these soils varied largely in their suitability for the growth of the test organism (B. prodigiosus). In some instances vigorous growth occurred; in others the numbers of introduced organisms fell to a minimum.

2. Treatment of the extracts by heat (which was supposed to result in the destruction of “toxins”) invariably led to still further bacterial decreases.

3. Extracts of soils treated with antiseptics (which are not supposed to destroy “toxins”) were on the whole more favourable for growth than those of untreated soils. Such extracts were found to have appreciably more organic nitrogen compounds than extracts of untreated soils.

From the foregoing account the following summary may be given:

1. Examination of Rothamsted soils on different occasions has revealed the presence of an organism capable of breaking down cellulose with comparative ease.

2. This organism presents a number of features of morphological and physiological interest. Morphologically, the organism appears to possess greater affinities with the Spirochaetoideae than with the bacteria and the name Spirochaeta cytophaga is, therefore, suggested.

3. While the spirochaet is capable of considerable vegetative growth as a sinuous filamentous cell, it also appears to pass through a number of phases which terminate in the production of a spherical body (sporoid) which differs in a number of respects from the true spores of the bacteria. Germination of the sporoid again gives rise to the filamentous form, which possesses perfect flexibility and is feebly motile. The latter does not apparently possess flagella.

4. Spirochaeta cytophaga is essentially aerobic; its optimum temperature is in the region of 30°. Both the thread and sporoid stages are killed by exposure to a temperature of 60° for ten minutes.

5. The nitrogen requirements of the organism may be met by a number of the simpler nitrogen compounds—ammonium salts, nitrates, amides and amino-acids. Peptone is also suitable in concentrations up to 0.025 per cent. Stronger solutions, e.g. 0.25 per cent., lead to marked inhibition of growth. The organism fails to grow on the conventional nutrient gelatine or agar.

The following Report on the contents of 311 pheasant crops presents the results of a very laborious investigation undertaken by Miss A. F. C.-H. Evershed during 1915 under my direction. Only those who have themselves attempted it will fully appreciate the amount of time and trouble involved in identifying the fragments of insects and plants met with in such a research.

For purposes of discussion of the problems of meat production the term “condition” may be defined as the ratio of the amount of fat to the amount of non-fatty matter in the body of the living animal, and the term “fattening” as any alteration in this ratio. Such alteration may result from (a) increase, (b) decrease in the amount of fat, (c) increase, (d) decrease in the amount of non-fatty matter. This, of course, implies that fattening may be either positive or negative and that the “increase” may be mathematically a minus quantity.

Very diverse views are expressed on the height to which water can rise in soils under the forces of capillarity. Alway and MacDole in the course of a brief historical review, point out that these estimates range from two or three feet only, to as much as two or three kilometres, although the majority do not exceed 200 feet. Most of the investigators who advance a high value for the capillary rise are careful to point out that in all probability the movement of water in this case would be exceedingly slow, owing to the excessive friction in the minute capillary spaces. Actual experiments on the rise of water in tubes of compacted soil result in low values, which are in all probability exceeded in the field. Warington in his book Physical Properties of Soil gives a typical table showing the results of Loughridgeb for Californian soils.

In a former paper, one of us has discussed the Palaeozoic soils of North Wales. In that paper, the Carboniferous soils were omitted as being rather apart from the other Palæozoic soils, which formed a convenient group for study by themselves. In the present paper, the authors discuss Carboniferous soils and the soils derived from the Northern Drift, together with the associated deposits of more recent origin.

The foregoing experiments give definite evidence, corroborative of the work of Koch, Remy and others, that the nitrogen content of sand or soil may be appreciably increased by the activity of Azotobacter when some suitable source of energy is supplied. For this purpose sugars such as dextrose and saccharose are suitable, but distinct gains have also been obtained by the use of plant residues. In laboratory experiments an increment of upwards of 6 mgrm. of nitrogen per gram of plant residues occurred, but in pot experiments gains of 9 mgrm. per gram of substance were obtained.

It is now accepted as a fundamental doctrine in animal nutrition that the prime function of food is to supply energy for the operation of the human or animal body and that all its other diverse uses are essentially tributary to this main purpose. The growing recognition of this fact in its relations to the nutrition of farm animals has given rise during the past twenty-five years to extensive investigations, especially by Zuntz and his associates, by Kellner and Köhler and by the writers, in which the attempt has been made to determine experimentally how much energy the various feeding stuffs can actually contribute toward the upkeep of the animal body.

An examination has been made of some of the extensive experimental data obtained by Bouyoucos and his associates on the freezing-point depression of soil solution at varying moisture contents, examined in situ.

These workers find that the soil solution in quartz sand and extreme types of sandy soil obeys approximately the same law as dilute solutions—the freezing-point depression varying as the concentration, or in the present case, inversely as the moisture content. In other words

where K is a constant, and Dn is the freezing-point depression, at a moisture content of Mn. Soils do not obey this law, the freezing-point depression rapidly increasing as the moisture content decreases.

1. The resistance of the hop-mildew (Sphaerotheca Humuli (DC.) Burr.) to polysulphide solutions varies according to its stage of development. The earliest stages after infection and antecedent to the production of conidiophores are the most resistant, requiring approximately a solution of double the concentration lethal for the “powdery” conidial stage. The “powdery” conidial stage occurring on young leaves is more resistant than the same stage on older leaves.

2. Conclusive proof has been obtained that with polysulphide solutions neither the total sulphur content nor the sulphide sulphur content gives an index of their fungicidal value.

3. The percentage of polysulphide sulphur in polysulphide solutions appears to be the factor determining their fungicidal value.

4. The fungicidal value of such solutions does not depend upon the nature of the polysulphides present.