Richardson's culture medium (urine) during insolation, and that this insolated urine possessed antiseptic properties. In this respect Richardson's experiments confirm certain previous observations made by Roux, but are in opposition to those of all other investigators who have devoted attention to this point. Thus Roux found that by the insolation of broth in the presence of air it became unfit for the germination of anthrax spores. Several other investigators, including Panzini and Janowski, have repeated this experiment with different culture materials, but have failed to confirm it. Roux's results were, however, so very definite that it has always seemed to me impossible to doubt their accuracy, and I have attributed the discrepancy between his results and those of others to some difference in the conditions under which the experiments were made. The definite proof which has now been furnished by Richardson that peroxide of hydrogen is formed in some culture media by insolation, and that the conditions necessary for the formation and preservation of this antiseptic substance are by no means perfectly understood, clearly shows that Roux and his opponents may both be right, and that the different results arrived at depend upon differences in the conditions under which the experiments were carried out, the nature of which differences is at present not understood. That Roux's insolated broth was rendered unfit for the germination of anthrax spores by the presence of peroxide of hydrogen is almost certain also from the fact that he found such insolated broth to recover its original nutritive properties if it was kept in the dark or in diffused daylight for a certain length of time.

2. The proof of the formation of peroxide of hydrogen during insolation naturally suggests the question whether the whole bactericidal effect of light is due to this material, or whether it only partially accounts for the phenomenon. This important question is one which it is far from easy to answer owing to the almost insuperable difficulty of securing conditions under which the generation of peroxide of hydrogen is impossible. We will examine some of the experiments which bear on this point:

(a) Downes and Blunt found that germs which had been air-dried on glass were destroyed by subsequent insolation.

(b) Momont found that anthrax spores dried for twelve hours by means of a sulphuric acid vacuum subsequently withstood insolation for upwards of 100 hours.

(c) Marshall Ward dried anthrax spores on glass at 70° C., and found that they were subsequently rapidly destroyed by insolation.

In none of these three sets of experiments can the conditions be regarded as precluding the possibility of the formation of peroxide of hydrogen. Moisture must certainly have been present in Downes' and Blunt's experiments, and in smaller quantity in Marshall Ward's. In Momont's experiments the desiccation was doubtless the most complete, and at first sight the long insolation endured by his desiccated spores is very significant; but I do not regard it as wholly conclusive owing to the impossibility of comparing the deportment of spores of different origin, and also to the fact that Momont used the more delicate method of detecting their vitality-viz., subsequent cultivation in broth-whilst Marshall Ward used, I believe, agar or gelatin; and Downes and Blunt, Pasteur solution-culture media which are not as sensitive as broth.

There are other experiments, again, which bear upon the same subject. Thus Richardson has shown that the formation of peroxide of hydrogen

is due to the presence of some ingredient or ingredients in the urine, and that it is not formed by the insolation of water, or even of a solution of area. If, then, the bacteria are suspended in water during insolation, there can be no generation of peroxide of hydrogen in the liquid. Now, as I have already pointed out in connection with my own experiments, a number of investigators are agreed that bacteria are much more resistant to insolation when suspended in water than when suspended in culture materials. It is, however, equally certain that they are actually destroyed, and sometimes even with great rapidity, when suspended in water. Now this at first sight would appear to demonstrate that the bactericidal effect of light, although accelerated by the generation of peroxide of hydrogen, may also take place without it. But we have already admitted the possibility of the generation of peroxide of hydrogen within the cells of imperfectly dried bacteria and their spores, so that it is surely still more easy to believe in the production of this material within the cells suspended in water to which air has access.

The evidence so far would appear to indicate, therefore, that, whilst the generation of peroxide of hydrogen is undoubtedly in many cases an active factor in the bactericidal influence of light, it is still uncertain whether it is indispensable for the process.

The question obviously raises another and far more general question which has long been before the chemical world-viz., as to how far oxidation can take place at all in the entire absence of water-vapour-and the evidence on this larger question goes entirely to show that all apparently direct low-temperature oxidations require the presence of water vapour. And, inasmuch as the bactericidal action of light is unquestionably a case of low-temperature oxidation there is the strongest presumptive evidence, as well as weighty experimental evidence, that water vapour, which practically means peroxide of hydrogen or some similar material, is essential for its manifestation.

One of the most important circumstances, from a practical point of view, connected with this bactericidal action of light is the greatly increased resistance which is exhibited by bacteria when suspended in water. On this subject I have for some time past been conducting some experiments, and although these are not yet by any means concluded, I may take this opportunity of referring to some of the results at which I have arrived. In the first place, I would point out how fallacious must be any comparison between the length of insolation withstood by even one and the same micro-organism in the hands of different observers, as so much depends upon their previous history and treatment. Thus I have found that the spores of anthrax produced at the ordinary room temperature (18-20° C.) are far more resistant than anthrax spores which have been obtained in an incubator at 35-38° C. It is necessary, therefore, in all such investigations, if comparisons are to be made, that the organisms should be taken from one and the same cultivation. In endeavouring to ascertain the greater susceptibility of bacteria to light when exposed in culture media I am proceeding by way of synthesis, making various additions to distilled water, and then determining how such additions affect the influence of insolation. In this manner I have already made some preliminary experiments with common salt and sodium sulphate.

The results of one series of these experiments are recorded in the following table :

Action of Sunshine on Anthrax Spores suspended in Water.
(PERCY FRANKLAND.)

Spores produced at 18-20° C.

3 hours' Sunshine

The figures refer to the number of anthrax spores contained in a cubic centimetre of water.

These results clearly show that the bactericidal action of light is very considerably greater in water containing common salt (1, 3, or 10 per cent.) than in distilled water; whilst, on the other hand, the addition of sodium sulphate in the same proportions has little or no influence in this respect. It is worthy of note also that an addition of 10 per cent. sodium chloride appears to exercise even a considerable bactericidal effect in the dark.

The specific effect of the sodium chloride in enhancing the bactericidal action of light is even still more conspicuously brought out by the series of experiments-also on anthrax spores-recorded in the following table:

Action of Sunshine on Anthrax Spores suspended in Water.

The figures refer to the number of anthrax spores found in a cubic centimetre of water.

In addition to those departments of bacteriology which I have briefly touched upon in this survey, there are many others, also of great interest to chemists, which might have been appropriately introduced had time permitted. Thus the more important subjects which I have had to pass

over are

1. The discoveries in the bacteriology of agriculture, including such important chemical changes as nitrification and the fixation of free nitrogen by leguminous plants (which must be regarded as some of the most important contributions to vegetable physiology ever made) have shown that really the most important fermentation industry, and which is far more extensive than all other industries put together, is agriculture.

2. The production of ptomaïnes and poisonous albuminoids.

3. The phenomena of natural and artificial immunity, including the much-vexed questions of phagocytosis and the bactericidal properties of blood-serum and animal fluids.

In all these branches of bacteriology there is not only much that is of interest to chemists, but there is urgent need in the interests of science that these subjects should receive the attention of chemists, for almost in every direction in which bacteriology is advancing it is abutting on problems which will require the most profound knowledge of chemistry for their elucidation. In many respects, moreover, chemists are at a great advantage in the investigation of bacteriological problems, inasmuch as their thorough experimental training and manipulative skill afford the very best preparation for the study of this subject, in which the inductive method and a due appreciation of all the complicating factors which surround an experimental inquiry are in continual requisition. It must not, however, be supposed that a chemist can apply any bacteriological method with the same readiness that he can carry out some new chemical preparation from a published description. In the management of living bacteria there are a number of points which have to be carefully borne in mind which do not enter into one's consideration in dealing with inanimate matter. But this step from the inanimate to the animate is not more difficult for the chemist than for the vegetable or animal morphologist; indeed, it is perhaps not as difficult, for, whilst the morphologist is occupied only with statical considerations, in modern Chemistry our attention is turned more and more to dynamical problems.

In view of the vast fields of fruitful research which lie in this province of Biological Chemistry, it appears to me that the curriculum of chemical training should be more and more framed with a view to their successful exploitation. It is desirable that chemical students should take zoology, botany, and physiology as subsidiary subjects more frequently than they do at present in order that the barrier which is often felt to exist between Chemistry and Biology may be broken down and abolished.

The Circulation of Underground Waters.-Nineteenth Report of the Committee, consisting of Professor E. HULL (Chairman), Rev. Dr. H. W. CROSSKEY, Sir D. GALTON, J. GLAISHER, PERCY KENDALL, Professor G. A. LEBOUR, E. B. MARTEN, G. H. MORTON, W. PENGELLY, Professor J. PRESTWICH, I. ROBERTS, THOS. S. STOOKE, G. J. SYMONS, W. TOPLEY, C. TYLDEN-WRIGHT, E. WETHERED, W. WHITAKER, and C. E. DE RANCE (Secretary). (Drawn up by C. E. DE RANCE.)

THE inception of this committee was due to Professor Hull, who was appointed Chairman at Belfast in 1874, with your reporter as Secretary, for the purpose of investigating the circulation of underground waters in the permeable formations of England and Wales, and the quantity and character of the waters supplied to various towns and districts from these formations. It was felt last year that the labours of the Committee were nearly completed, and that they could not terminate their labours at a

more appropriate place of meeting than Nottingham, supplied as it is by a magnificent volume of underground water of absolute purity, and it is of interest to note that the Chairman of the Committee, Professor Hull, was consulted when these works were first initiated by the late Mr. M. D. Tarbotton, C.E.

It was last year resolved by the General Committee that your reporter 'be requested to draw up a final report embodying the whole of the facts obtained in counties,' and 'that it is advisable that the report in question should be issued as a separate publication.'

In compliance with this resolution your reporter has commenced the work of combining and systematising the previous eighteen reports, but he regrets that through pressure of official and other duties it has been impossible for him to complete the same, but he trusts to do so before the meeting at Oxford in 1894, when your committee will complete the twentieth year of their existence. The counties will be divided into five groups, and the report into as many separate sections, which your Committee recommend be sold separately.

Your reporter would in any case have ventured to suggest the continuance of the Committee for another year, in consequence of the exceptional season experienced, which has rendered it highly important to endeavour to trace the effect of the drought on underground water supply, and to institute a special inquiry as to the downward movement of the underground water line throughout the porous rocks of the country, and also as the rate of replacement of water by subsequent rains.

From observations made by Mr. E. J. Lowe, F.R.S., at Shirenewton Hall, Worcestershire, it appears that the entire rainfall of March and April was only 0.6 in., that from March to August 17 only 9.7 in., that 48 rainy days occurred, and 122 days without any rain: this, combined with an almost continuous high temperature, caused excessive evaporation of such rainfall as took place, the shade temperature being above eighty degrees seven days in April, one in May, six in June, five in July, and eight in August up to the 17th. Before the thunderstorm of June 15, on which 101 inch fell, the ground was dry to a depth of fifteen inches, but the rain only penetrated two inches from the surface.

The drought has made clearly apparent the weakness of gravitation supplies, the quality of the water in the best reservoirs steadily deteriorating as the quantity stored is reduced. The great value of underground supplies is as strongly brought out by the present yield of the Gainsborough Local Board well. It was sunk by Messrs. Timmins, Runcorn, at the recommendation of your reporter. The boring is now 1,351 feet in depth, and gives, in spite of the drought, the magnificent yield of 20,000 gallons per hour. The boring is artesian, the water rising from beneath 725 feet of Keuper Marls, being derived from the New Red Sandstone several miles distant.

Your Committee seek re-election, and reserve details received this year for incorporation in their final report next year. The Committee regret to have to note the death of their able Leicestershire member, Mr. James Plant, F.G.S., whose work has been of great value to the Committee and to the inquiry generally.