Moggridge states that he has found abundant proofs that they descended to the level of the present Mediterranean, near Mentone.* If, at the time the Atlantic ice and that of the southern ranges I have mentioned blocked up the drainage of Europe, the upper end of the Northern Pacific was also filled with ice, or only so far as the mountains of Kamtchatska, a great continental basin of water would be formed, rimmed in on its southern side by the ranges of mountains that extend from the extreme north-east of Asia to the Alps. The only break now existing in that rim is through the Bosphorus, and both physical geographers and naturalists have come to the conclusion, on independent grounds, that the Black Sea did not communicate with the Mediterranean until after the close of the Tertiary period, and the excavation of the channel that connects them must have been effected about the time of the Glacial period. Probably it was made when the whole drainage of northern Europe and Asia was intercepted and turned in that direction. That the waters of the Great Lake flowed that way is indicated by the Scandinavian drift having been carried far over the plains of Russia, and by the vast extent of diluvial clay spread out around the north-western shores of the Black Sea. In this way I consider the waters were raised, over which floated icebergs from the north carrying the Scandinavian drift, and into this great lake the Danube and the Rhine, or the upper portions of them above its level, brought down fine mud from the glacier-capped Alps, which was deposited as loess. The waters everywhere were muddy, for glaciers were still triturating the mountains of Scandinavia, and thus the fine clay was spread over Europe as far as the lake extended. The very fact that the glacial waters carried fine mud in suspension to such great distances is another proof that they were fresh, for it has been abundantly proved by Dr. Sterry Huntt and others that in salt water mud is quickly precipitated, whilst in fresh it remains a long time in suspension. I think there is evidence that the lake reached a height of 1700 feet above the sea, and that it remained for a long time at about 1200 feet. It was once completely drained; at first gradually, but from about 500 feet above the present level of the sea suddenly and tumultuously by the breaking away of the icy barrier, and thus was produced a great deluge or debacle that swept over the lower lands and Proc. Geol. Soc., London, 1876, p. 127. covered them with a mantle of false-bedded sands and gravel. The evidences of this debacle were insisted upon by the last generation of geologists, and they are to be found everywhere over the south of England; but of late years they have been almost ignored, Prof. Prestwich being, I think, the only one who still advocates the old theory. After being thus broken, the icy barrier soon closed up again, and the great lake was reformed, and this time was much more permanent, and probably existed until the communication between the Black Sea and the Mediterranean was cut through. The areas with which this paper has had especially to deal are at an altitude of more than 500 feet, and no traces of the debacle could be expected, though I think there is evidence of the more gradual lowering of the upper part of the first lake in the separation of the loess into two divisions, as at Wurzberg. It is to the first rising of the waters that I attribute the destruction of the mammoth and the woolly rhinoceros, and probably of palæolithic man in Europe. The evidence is perhaps not so conclusive with regard to palæolithic man, but as concerns the two great quadrupeds it is clear and decisive. I can find nowhere in Europe a trace of their existence after the first rise of the waters. In the great debacle their bones were carried and spread out over the low grounds along with the lowland gravel, and doubtless often carried unto the top of low-lying patches of boulder clay, but in these cases they are broken, single, or rolled. And in the valley of the Rhone, as the great advance of the Alpine glaciers preceded by a long time the culmination of the ice of the Atlantic and Pyrenees, and the destruction of the great mammals did not take place until the approach of the latter event, there are apparent proofs of their postglacial existence, but the evidence only shows that they lived after the culmination of the Alpine ice, not after that of the Glacial period. The evidence of the latter is not the glaciation of the rocks of the Rhone above Lyons, but the gravels and clays spread out in the same area by the great lake when there was a high ridge of ice to the southward and that of the Alps had shrunk back. Probably palæolithic man, the mammoth, and the woolly rhinoceros survived through the culmination of the Glacial period in Asia, though the two quadrupeds soon afterwards became extinct. Mr. Boyd Dawkins and Sir John Lubbock have given cogent reasons for supposing that the Eskimos are the descendants of palæolithic man, and they still survive in north-eastern Asia. I found evidence when I crossed Siberia in 1873 that the high lands to the north of the Altai had not borne glaciers even in the Glacial period, and they would thus afford a refuge from the great flood. But in western Europe most of the land that was not submerged was covered with ice, and there were few places of safety to flee to. What few there were, were in the east of Europe, and therefore it is, I think, that after the Glacial period passed away the animals that survived mostly spread from the south-east across Europe again, and only a few had reached England, and still fewer Ireland, before the waters of the ocean resumed their old channels, and cut off the communication with the Continent. After the Glacial period, neolithic man, who had probably lived to the south and south-east for ages before that time, found central and northern Europe open to him. Not only the mammoth and the woolly rhinoceros had been destroyed, but, what was of much greater importance to him, the great Carnivora-the cave bear, the lion, and the tiger. The whole of northern Europe had also been covered by the fertile mud deposited from the Great Lake, and thus in every way the conditions of existence had been made more suitable for him. The Glacial period is thus invested with a double interest; it is the first step backward in geology, the first forward in archæology, and in neither sciences can we make our footing secure until we clear away the doubts that beset us here. I claim for my theory that it shirks none of the difficulties and embraces all the facts. I have only dealt with a few of the problems in this and other papers, but I hope to find time to show in future communications that the theory affords a key to all. I can only trust that through time the faith of geologists in great upheavals and depressions of the earth's surface within a comparatively short period, in the possibility of the ocean having covered vast continental areas and retired without leaving any marine remains behind it, and in a succession of glacial periods having alternated with inter-glacial warm ones, will be shaken, and that they may look more favourably upon a theory that explains all the phenomena by one great advance southwards of the ice of a single glacial period. VI. PHYSIOLOGY AND ITS CHEMISTRY AT HOME AND ABROAD. By CHAS. THOS. KINGZETT and HENRY WILSON HAKE. HE acquisition of any new and important fact in any branch of Science, in affecting more immediately that special branch whose pursuit has led to its discovery, exerts a further influence throughout all Science, which, in its gradual but universal action, may not inaptly be compared to the unlimited progress of a concentric wave. Not a few sciences owe their origin to the discovery of a single fact. Thus the discovery of Frauenhofer's lines gave rise to the great Science of Čelestial Chemistry. In similar wise the Chemistry of the Carbon Compounds dates from Liebig's elaboration of the methods of organic analysis. So great was the impulse communicated by this perfection of method that from darkness it has led us to darkness again; for, in teaching us the composition of bodies, it has brought us to isomerism. When a new method of investigation shall impart a new impulse we shall again emerge into light. The influence thus originating with Liebig did not extend alone to pure chemistry; at the same time an impetus was given to Chemical Physiology, so brilliantly exampled by the work of Liebig himself. Progress has not, however, in the case of this Science been nearly as rapid as in the sister Science, and for obvious reasons. While Chemistry itself was by no means a new science, Physiology scarcely merited its name. Up to the time of which we are speaking physiologists had concerned themselves only with the study of anatomy and life functions, so far as these could be observed and explained without the aid of chemical science. Physiology, then, was at that period a science of observation and deductive reasoning, while metaphysical speculations entered largely into its narrow sphere. Liebig perceived that it was futile to appeal to the preconceived opinions of his contemporaries, and as regarded their metaphysical views he argued that such must render men powerless in time to perceive the relations of cause and effect. He devoted himself with much earnestness of purpose to expose the unscientific methods of reasoning and research then so prevalent among physiologists: he therefore addressed himself to a younger generation, and strove to impress their more plastic minds with the principles of that inductive method of reasoning so ably interpreted by J. S. Mill, and of which he was so professed an admirer. Thus he gathered around him a group of men who, by adopting and disseminating his teachings, gave rise by their labours to a new epoch in Physiology and its Chemistry. And this brings us to the subject of our Essay. Let us put ourselves at once en rapport with the reader as regards our immediate object in writing it. Since the time above alluded to, while opportunities for advancement have been daily increasing, the study of Chemical Physiology has, in many respects, deteriorated. There is a necessity for reform. A reference to a few researches in Physiological Chemistry, published in certain leading scientific journals, will serve to substantiate this statement. We will commence by considering the alleged discovery of a new body, to which has been given the name of "nuclein." We shall enter into a minute account of this body, because its history is typical of a hundred others of a like kind. Its first appearance was in 1871, in which year a paper by F. Miescher* appeared in "Hoppe-Seyler's Med. Chem. Untersuchungen." It was regarded as a peculiar albuminous body, rich in phosphorus, and as constituting the principal component of the nuclei in pus-cells. Lubavin* next obtained an "entirely similar body" by long-continued digestion of milk-casein with artificial gastric juice. Dr. P. Plosz* states to have obtained the same body from the bloodcorpuscles of birds and snakes, and also from brain albumen. Hoppe-Seyler* obtained, further, a substance from yeastcells which he compares to "nuclein." Ignoring details, for the moment, "nuclein" is said to be obtained from these various matters after they have been freed from substances soluble in water, dilute acids, alcohol, ether, &c., by a process of artificial digestion with dilute hydrochloric acid and pepsin. The body in question is soluble in alkaline solutions, and has, as admitted even by those who have worked with it, the further general characters of a form of albumen. Thus it gives a xantho-proteic reaction with nitric acid, and its soda solution gives no reactions which can be said to be characteristic of a new substance. From this it will be seen, the only evidence that the body is at all new to science consists in its contained phosphorus. More recently Dr. Miescher, of Basel, asserts once more to have obtained this "nuclein" accompanying "protamin" (of which more anon) MALY, Jahresbericht der Thier-Chemie für 1874. Wiesbaden, 1875. + Ibid, p. 337. |