The results of the work may be briefly summarised as follows:

(a) The rate of fermentation of ciders and perries made from different varieties of vintage fruit varies considerably.

(b) There is probably a relation between the rate of fermentation and the variety of fruit from which the cider or perry is made. Certain varieties, for instance, as a rule yield juices which ferment slowly, while others give juices which generally ferment at a rapid rate.

(c) The main factor in determining the rate of fermentation appears to be the nitrogenous matter present in the juice, which is assimilable by the yeast. The quantity of such substances present is generally insufficient for satisfactory nutrition of the yeast, and consequently the rate of fermentation is normally slower than would be the case if sufficient nitrogenous food were present to meet the full requirements of the yeast. The relative rates of fermentation of ciders and perries fermented under similar conditions are probably an index of the relative amounts of assimilable nitrogenous matter present.

(d) The state of ripeness of the fruit at the time of milling affects the rate of fermentation of the juice. During the course of ripening the rate becomes slower until a certain point is reached, which probably represents the period of perfect maturity of the fruit. Afterwards the rate increases in proportion as ripeness proceeds to decay. The degree of exposure of the fruit to direct sunlight also affects the rate of fermentation, the more exposed the fruit the slower the rate. In each case the result appears to be due to the quantity of assimilable nitrogenous matter in the juice being influenced.

(e) Direct influence on the rate of fermentation of the juice by any of the chemical constituents other than the nitrogenous substances has not been observed. If any have an influence, it is masked by other factors of greater importance. An indirect influence on the rate by the mucilaginous elements is occasionally met with, due to the formation of a clot which mechanically impedes the action of the organisms of fermentation.

(f) The rate of fermentation in practical cider-making does not appear to be materially affected by the fermentative powers of the kinds of yeast present in the juice. Normally there are present varieties which are capable of maintaining the fermentation at practically the maximum rate allowed by the nitrogenous constitution of the juice. “Dominant” fermentation with selected yeasts of high or low fermentative powers had comparatively little effect upon the rate.

(g) The aeration of the juice has a marked effect upon the rate of fermentation, the admission of air to the juice producing a decided increase in the rate.

(h) The temperature at which the fermentations are conducted affects the rate in the customary manner.

It is clear, therefore, that apart from the use of purely practical methods, e.g. filtration,—which it is not intended to consider here— a certain measure of control over the rate of fermentation of ciders and perries can be exercised by the cider maker, and that therefore the production of sweet and dry types of these beverages need not be more or less haphazard, as is commonly the case. By careful selection of the varieties of fruit used and by suitable blending of various types, combined with attention to the condition of ripeness of the fruit at the time of making, it should be possible to obtain a juice possessing the desired rate of fermentation, although some allowance for seasonal influences is necessary. These have not been considered above, as the work has not been extended over a sufficiently long period to allow of definite conclusions being drawn. At the same time it is fairly established that in some seasons the average rate of fermentation is much faster than in others. It would appear from the results as to the effect of direct sunlight as though the amount of sunshine during the period of ripening of the fruit upon the trees played an important part in seasonal influence. During the course of fermentation of the liquors the rate may be controlled to some extent by aeration and temperature.

Although the subject has been considered almost entirely from the point of view of the rate of fermentation, it should be mentioned that not only the rate but also the degree to which fermentation proceeds is involved. Although perhaps not invariably the case, as a rule fermentation can proceed to a further point in rapidly than in slowly fermenting juices. Accordingly no distinction has been made between them. In some cases the latter feature would more correctly express the facts than the former.

In conclusion I take this opportunity of expressing my indebtedness to Mr James Watts for his kindness in placing his factory at my disposal for experiments with selected yeasts; to the many cider makers and others, who have rendered considerable assistance in the direction of obtaining different varieties of vintage fruit required for the work; and to the various members of the staff of the Institute, who have carried out the practical work in the cider house.

The importance of a “well balanced” ration in feeding animals has long been recognised, and most intelligent stock-keepers pay some attention to the albuminoid ratio of the foods they use.

When soils are treated with antiseptics, such as carbon disulphide, chloroform, benzene, ether or paraffin oil, they undergo chemical change, and the soluble organic matter in them is increased, just as in case of their being heated; they also exhibit the same inhibitory effect on the germination of seeds that heated soils do.

The different antiseptics differ in the intensity of their action, but the inhibitory substance formed is probably the same in all cases, and also the same as that formed by heat, for the quantity formed has the same effect on seeds, whether produced by antiseptics or by heat.

On keeping treated soils for a few weeks at a summer temperature, some of the organic matter which was rendered soluble becomes insoluble, and the inhibitory action is reduced. This is also the case with heated soils, especially when repeatedly watered; though with unheated soils under similar conditions the soluble organic matter increases.

The treatment of soils with antiseptics induces a change equivalent to that obtained by heating the soil to 60°—75°, and this may be sufficient to account for the increased growth observed in plants grown in them.

The production by heat of a substance inhibitory to germination appears to be a property common to all soils, twelve instances having been examined: the proportion of it formed depends on the increase in the amount of organic matter rendered soluble by heating; but the actual amount of the soluble organic matter in the heated soil is not always a criterion as to the intensity of its inhibitory action, and still less is the amount of soluble organic matter originally present in the unheated soil, though in the majority of cases it may be so. There appears to be no connexion between the fertility of a soil and the extent to which it is altered by heating.

Soils in their natural state appear generally to contain a certain amount of this inhibitory substance, as they act less favourably towards germination than pure water does: whether in any cases soils can act more favourably than water—as the earlier experiments had indicated they could—is open to doubt, but the probability is in favour of their doing so. So far as the instances now examined are concerned, the richer soils, and those containing most soluble organic matter, are slightly less favourable to germination than the poorer soils.

The work described in this paper deals exclusively with the yeast flora of certain bottled ciders. It was undertaken as a section of an extensive scheme of investigation of the organisms which are concerned in the fermentation of English-made ciders. Apart from the more purely biological side of the question the main objects of the whole scheme are to determine how far the customary method of conducting the fermentation of cider in this country is satisfactory, and whether it could be improved, from a practical point of view, by certain modifications or by the substitution of other processes, such, for example, as the use of selected yeasts.

All classifications of soils yet proposed may be divided into two groups: (a) scientific classifications which are based on the natural characteristic of the soil, and (b) “applied” classifications which are based on the suitability of soils for certain crops, or on the revenue that may be derived from them.

The experiments carried out by the Home Grown Wheat Committee of the National Association of British and Irish Millers have demonstrated the important fact that certain varieties of wheat retain their strength under our conditions. One of the best known of these varieties is Red Fife, the grain of which forms the basis of the graded wheat known as Manitoba Hard. Red Fife has now been tested in this country for six seasons and its strength is still found to be equal to that of the same variety when grown in Canada. Further a somewhat impure stock of the same variety has been cultivated in the Midlands for some sixteen seasons without showing any signs of diminution in strength. As grain of this character is considerably more valuable than that generally grown in this country and as there is a steadily increasing demand for it, the Committee recommended the experimental cultivation of Red Fife in various parts of the country. The results of these trials have shown that in some localities Red Fife will produce more profitable crops than any of the common English wheats, though in others its yield is too small for its profitable cultivation. In spite of very complete returns furnished by growers in most parts of the country it seems impossible at present to state with any precision what the factors are which determine whether it can be grown successfully. Its extended cultivation has also brought out the fact that the straw is not as rigid as the farmer would wish it to be and more than one grower has condemned the variety on this account.

Although the study of the action of Bacteria in pathogenic relation to the higher plants may be described as in its infancy, a great deal of sound work has been done in this branch of Phytopathology, and various types of bacterial diseases have been definitely established.