All this might seem going a little far afield were it not for two noteworthy facts. The first is that old age is in some sense merely accumulated fatigue; the second is that one very striking condition, if it be not an essential condition, in old age, is lessened oxidation.

Whatever else may be its role in the vital chemism, we know well enough nowadays that a great and essential office of oxygen lies in neutralising, removing, preventing the accumulation of the natural poisons produced by the bodily activities. Conceivably lessened oxidation means an accumulation of these toxic products, which results in senile decay. If this were true, then if we could get hold of some way of maintaining and stimulating this oxidising process, we should get a long way in the maintenance of youthful vigour.

Here again we have just a clue. A Russian pathologist, Belonovsky, has recently shown that the hemolysins, the poison serums which in quantity destroy red corpuscles, stimulate the production of the corpuscles when administered in very minute doses. This discovery has already been utilised to good effect in the treatment of the familiar disease of anæmia. Whether it will be of avail in warding off the kindred conditions of old age remains for the future to show.

VIII

We here reach the borderland of acquired knowledge. What lies beyond we can only conjecture. The enormous body of more or less connected knowledge already built up, regarding the vital chemism, the rôle of the ferments, the serums, the anti-toxins, the body destroyers and the body builders, can hardly fail to prove a powerful engine for further advance. The marvellous progress realised in the past thirty or forty years will not stop short now. It is but a halting imagination which conceived that it will cease before it has reduced all vital phenomena to the action of known chemical and physical forces.

And this complete descriptive knowledge is but the prelude to the higher achievement which is the more or less conscious aim of all rational scientific investigation; this, in the phrase of one of the most distinguished of presentday physiologists, is the control of phenomena.

At the present moment the especial need in the study of old age is concerted investigation. There is need first of all of a complete and accurate knowledge of the changes in which old age consists. As yet the facts are slight. Instead of the finished picture we have but a bald sketch. Investigators can be had in plenty; the need is money, and its intelligent expenditure. Amid all the millions so recklessly thrown about nowadays, the half of it perhaps with little chance for gain or good, surely it seems as if some of it might be diverted for a thorough exploration of this little known field.

It is curious to reflect what might already have been achieved if twenty years ago even a slender corps of investigators could have been set at work with adequate funds. Possibly some Mecanas may yet arise, interested enough, either on his own account or for his kind, to look forward to what might be realised ten or twenty years hence if we begin now-and set the search going.

DR. CARL SNYDER.

THE EFFECTS OF CIVILISATION

A

UPON CLIMATE

LTHOUGH men in their pride may on occasion think otherwise, nothing can alter the eternal purposes of Nature. Over and above the fretful workings of humanity, the great mother, supremely calm, pursues the even tenour of her way. Countless generations may come and go, each more energetic than the last, vast and far-reaching schemes be carried into effect, yet "they shall all wax old as doth a garment." Nevertheless, it would be idle to deny that mankind is often able, for a while at any rate, to work in opposition to natural laws; any mark which he may leave, however, will be purely temporary, to be effaced completely by the passage of time. Still the fact remains that the human race may continue to hold its own against the forces of nature over a comparatively long period.

One of the most interesting points which arise out of the consideration of man and the natural world is the question as to whether the developments of civilisation may in any way affect the climatic conditions prevalent in the different countries of the earth. The subject is not by any means new, neither is it one concerning which there is universal agreement. Indeed, it is an oft debated matter upon which many authorities find themselves at variance. By some it is positively asserted that the relatively tiny efforts of man cannot have the least power to bring about meteorological

change; and, whilst one fully appreciates the insignificance of human endeavour, yet the evidence which can be brought forward in favour of the theory of artificial interference with climate serves to show that the idea is not such a fanciful one as some would have us believe. There is no doubt that when the possibility of artificial climatic change was first mooted a great deal of exaggerated statement was brought forward, and in recent years there has been a strong tendency to discredit the theory as a whole on the ground that so many of the original assertions have been proved to be entirely fictitious. The question is very fascinating and one of peculiar interest to the citizens of the vast British Empire, which in its many parts, covering one-fifth of the globe, is subject to every conceivable form of climatic condition.

It has always appeared to the writer that people who scout the idea of anything that man may do affecting the weather (putting aside the question of climatic change for the moment) can scarcely realise the extremely local character which is often a feature of meteorological conditions. An instance like the following is no uncommon happening: In a particular district fine, bright weather may be constant throughout the day, whilst a few miles distant heavy storms of rain will be experienced. This clearly shows that the area over which a particular type of weather is prevailing may be comparatively small in extent. Viewed in this light it does not seem so difficult to believe that in a given locality the weather might be influenced by some artificial feature. We need not go very far away to find an incontrovertible proof that this is so. No one will say that the huge city of London does not affect its own weather. The volume of smoke which arises from hundreds of thousands of chimneys turns day into night on many occasions when it would otherwise be fine and sunny. Moreover, the smoke from the great city is not only obnoxious within the borders of the metropolis, but its influence is felt over a much greater tract of country than is generally supposed. In Berkshire, forty miles away

from London, an observer has remarked that the prevalence of an easterly wind during a number of hours frequently results in the sky being overcast with dull yellow clouds, evidently charged with sooty smoke. The people of the Oxfordshire hill villages are well acquainted with the effects of London smoke, and even during bright summer weather, should the wind happen to shift to the right quarter, the clearness of the atmosphere will be obscured by a blue haze and a distinctly sulphurous smell will be noticeable in the air. Of course, it may be truthfully said that London does more than influence its weather-it affects its climate as a whole. Even in the finest weather the canopy of sky over the metropolis is more or less obscured by the smoke veilit is never entirely clear.

The presence of a large number of buildings in any situation will raise the temperature of the locality, whilst the influence of the warmth arising from a large number of fires must not by any means be overlooked. Experiments conducted in London, Berlin, and Paris serve to show that the average annual temperature in the cities is two or three degrees higher than in the surrounding country. At certain times of the year there is often a greater difference still, and it is noticeable that in cities sudden changes are not felt to the same extent that they are in the open country. In fact, we may imagine that London is enveloped by a great covering of warm air, which serves to repel the onslaughts of cold, for a time at any rate. Most people must have noticed how the trees and shrubs in the London parks burst into leaf a good deal earlier than is the case with specimens under less sheltered surroundings, and we may take it that plants are the best guarantee as to the mildness of any situation.

After all, of course, London and its like are not very big matters as far as area is concerned; at best the influence which these cities may bring to bear will extend not more than a few square miles. It will be necessary to push the point of the possible effects of civilisation upon climate to a much greater