The biochemical decomposition of plant residues and other organic matter in the soil is of fundamental importance for soil fertility. It causes the breaking down of coarse plant fragments which otherwise might open up the soil too much: it leads to the production of colloidal complexes known as humus which exert many beneficial effects both chemical and physical, and it brings about the formation of nitrates, the most important of the nitrogenous plant nutrients.

It has been known from the earliest times that soils would remove salts and colouring matters from solution and the problems arising out of the observations made on this phenomenon were among the earliest to be attacked by agricultural chemists. It was known to Aristotle that sea water lost some of its taste by filtration through sand and this observation seems to have been confirmed and applied in many ways. Lord Bacon in his Sylva Sylvarum discussed the question of making sea water potable by filtering through sand. Le Comte de Marsilli made quantitative experiments. Sea water was filtered through fifteen successive vessels of garden soil and a diminution in the salt content was proved by evaporation and by the change in specific gravity. Similar results were obtained with sand. Boyle Godfrey discussed the question of making sea water fit for use on ships and observed that if sea water be put into a stone straining cistern the first pint that runs through will be like pure water, having no taste of salt, but the next pint will be as salt as usual. Stephen Hales in dealing with the same question refers to the use of a soft stone by the Dutch as a filtering material, but he points out that this method has no practical value as only the first portions of the filtrate are free from salt.

1. A bacillus isolated from celery affected by soft-rot reproduced the disease when inoculated into celery plants.

2. Other vegetables commonly grown as garden crops are susceptible to attack by the same organism.

3. The bacillus is very sensitive to the action of antiseptic and germicidal reagents.

4. It is typically bacilliform but under certain conditions may be almost isodiametric and coccus-like, or it may develop into very long filaments.

5. It is capable of growing in a synthetic medium containing a sugar or pectin as the sole carbon compound.

6. Its group number is 221·1113522 and since B. carotovorus Jones proves to be a yellow organism the latter must also be included under that number. The two organisms appear to differ slightly on minor points, e.g. vigour of growth in Uschinsk's solution and on celery extract agar.

7. Like B. carotovorus the celery-rot organism is very sensitive to desiccation.

A Short preliminary note on this disease was published Nov. 1912(4), and since that date further investigations have been carried out into the life-history of the organism, and its effect on the host plant. As 1 there showed the disease is caused by a bacterium for which I propose the name Pseudomonas seminum.

Points of considerable interest, both scientific and practical, are raised by the question as to whether a tree which fruits exceptionally well as compared with its fellows in one season, will tend to fruit exceptionally well, or the reverse, in the following season. We know of no definite reason why the behaviour of a tree as regards fruiting should alternate in consecutive years, and no such behaviour has been observed in the case of animals. Its doing so would imply that fruiting is due to the gradual accumulation of some substance in the tree, which becomes exhausted whenever heavy bearing occurs, and that the stock of this substance does not become properly replenished till after another season has elapsed. This is quite possible, but quite unproven. Indeed it seems to be actually opposed to the well established fact that growth and fruiting are antagonistic to each other; for the exceptionally feeble growth which accompanies exceptionally heavy cropping, must tend, as all restriction of growth does, to the formation of an increased number of blossom-buds for the following season, and probably, therefore, to heavy cropping also, during that following season; unless of course, the cropping has been so heavy as to seriously impair the vigour of the tree; but this is an excessive condition which need not be considered here. We might also expect similar behaviour as regards fruiting in consecutive years, on the general grounds that individual trees must differ from each other in fertility, as in every other respect. On the other hand, there is a strong belief amongst horticulturists that a tendency to alternate fruiting, as it may conveniently be termed, does really exist; so much so, that the recommendation is often made, to severely thin the fruit from a tree which is bearing heavily, with the object of destroying this tendency, and of obtaining moderate and more uniform bearing in future years.

A disease, which is due to a hitherto unrecorded attack of eelworm, has been found causing a considerable amount of damage to black currant plantations in the vicinity of Cambridge.

The organism which produces “Blackleg” of the potato in Lancashire is B. atrosepticus (van Hall).

It is in all respects identical with the organism responsible for this disease in Ireland and described by Pethybridge and Murphy under the name B. melanogenes.

We can now bring together the various results obtained during the course of our investigations.

We find that the changes are at a minimum under anaerobic conditions, and they are as follows:

1. In the laboratory experiments as much as 17 % of the dry matter may be converted into gas: in the heap the proportion is less.

2. The non-nitrogenous constituents are particularly affected, as much as one quarter of the pentosans may disappear during the process and other constituents break down in like proportion. The gas evolved contains carbon dioxide, marsh gas, and hydrogen.

1. When salts or minerals containing phosphoric acid are ignited with ammonium fluoride as in the ordinary process of analysis of silicates, considerable loss of the phosphoric acid may occur. It is probable that the phosphorus is volatilised in the form of a phosphorus fluoride.

2. The loss is least in the case of salts containing an alkali metal. It is less in the case of disodium hydrogen phosphate than in that of potassium dihydrogen phosphate, and is greatest in the case of phosphates of the alkali earth metals, such as calcium phosphate or apatite.