Within recent years, Kellner's system of starch equivalents has received much criticism from various quarters, and its value as a practical feeding system has been called into question. That the system is far from perfect in its working is universally admitted, and the recent work of W. Bruce with oxen has done much to emphasise this fact. In a series of practical feeding trials with oxen, Bruce obtained results contrary to those expected from the theoretical consideration of the Kellner system of starch equivalents, and largely on account of this work, and partly on account of the demonstration of the importance of the part played by certain unknown chemical compounds in the normal metabolism of animals, many workers have been led to suggest a total abolition of the Kellner system. It is, however, inconceivable to the author that a system based on 30 years continuous research upon feeding problems, should be condemned without the fullest possible enquiry. Furthermore it is supported by many experimental results. In a critical comparison of the values of certain foods for milk production theoretically computed by the Kellner system, Crowther has shown that the results obtained with one exception agree very well with those obtained in actual feeding practice. Moreover, with regard to the food deficiency factors which play such an important role, in the normal metabolism of animals, Hopkins has shown that those factors are hardly likely to be missing in normal dietaries, and consequently the results obtained in ordinary feeding trials will rarely be affected by lack of these factors.

The hop plant Humulus lupulus L. is best known in Britain from its cultivated forms grown for use in the brewing industry. Those varieties which are grown on a commercial scale in this country all conform to the general description of Humulus lupulus L. and the presumption is that they are all variations (directly, or indirectly through other varieties) from the female form of the original wild hop. Since the plant is dioecious it follows that any one of these varieties was in all probability derived primarily from one ♀ plant which arose either as a mutation or as a hybrid and has subsequently been propagated vegetatively by cuttings or “sets,” i.e. the variety is represented by a number of plants comprising a clone; such a variety is not necessarily provided with a corresponding male form possessing all the vegetative characters of that particular ♀ variety.

On January 3rd, 1915, the Little Ouse burst its right bank not far from the Feltwell 2nd District Pumping Station, and as a result thousands of acres of fenland became flooded. The portion of the flooded land on which the following observations were made is a part of Southery fen situated near Southery, Norfolk. It lies between Peckett's Farm and Turf Fen Farm, and belongs to the Norfolk County Council. This land is some distance from the place where the burst occurred, and as a consequence there was no deposit of silt. The height of the flood here was about nine feet. The water was gradually pumped off and the land cleared by September, 1915.

The experiments reviewed in the preceding pages have been carried out on a light loam soil very poor in lime, in a district of medium rainfall (20–25 inches).

The chief conclusions drawn from the results are as follows:

1. Although the heaviest crops have been obtained with an annual application of dung, they are little heavier, and more costly to obtain, than the crops obtained with a biennial application of dung, especially if in the alternate year a light dressing of “artificials” including nitrate of soda be given.

2. A complete mixture of “artificials,” including nitrate of soda, has given good average crops, but not equal to those given by a biennial application of dung.

3. For the soil and other conditions of Garforth nitrate of soda is distinctly better for the hay crop than sulphate of ammonia. This is doubtless largely associated with the poverty of the soil in calcium carbonate.

The dipping of sheep and cattle, as a means of eradicating ‘scab,’ lice, ticks, etc., and the diseases which it is now known the latter may transmit, has met with such success, that compulsory dipping is now in vogue in most pastoral countries. Where compulsory dipping obtains, there must of necessity be some system of the standardisation of dips. In Queensland and South Africa, the respective Governments issue official formulae from which the stockbreeder can prepare his own dipping fluid. Only such proprietary dips, as are duly recognised by the Government, may be employed. In the United States, the regulations for the sale of proprietary dips are still more stringent. The quantity of active substance, usually sodium arsenite, nicotine or cresylic acid, is defined within very narrow limits. Further, no proprietary dip is now recognised, unless the manufacturer can furnish a ‘Field Tester,’ by means of which the stockbreeder can himself determine, in a simple and fairly trustworthy manner, the percentage of active constituent in his bath.

At page 5 of their recent communication on the composition of soil gases Messrs Russell and Appleyard give some data regarding gas which was extracted from portions of soil which had been placed in flasks, the air pumped out and the soil then allowed to stand for one or more days. The authors state that “the total amount of gas given up is not great.” As a matter of fact a little consideration shows that the volume of this gas was indeed comparatively very large.

In Part III of this series of communications we recorded that no mammary pigment could be found in the old sows that were examined by us, and we suggested the possibility that such pigment had previously been present and had been destroyed or removed during the periods of glandular activity.

The decay of plant and animal residues in soils produces brown organic compounds commonly designated as humus. Some of it is soluble in dilute alkaline solutions, and agricultural chemists and investigators have often assumed that this part plays an important function in the nutrition of plants by reason of its solubility. As a result numerous methods have been devised for determining this readily soluble material, and its amount has been regarded as a measure of the fertility of the soil. Since however the amount of nitrogen in the soluble humus material is commonly 40 per cent, to 50 per cent, of the total nitrogen, the results for ordinary soils gave no better indication of potential fertility than did the total nitrogen determination itself.