March 23. 1893] 



NATURE 



485 



and the division of the "generative cell " ; but occasion- 

 ally they persist somewhat longer, and Strasburger 

 figures a pollen-grain in which the three prothallium cells 

 are intact, and the first of them has a partition at right- 

 angles to the walls of the other cells. In this work 

 Strasburger also gives the results of some experiments on 

 the colour-reactions of the male and female nuclei. Rosen 

 discovered that, as in animals, the male nucleus of 

 phanerogams is kyanophilous and the female nucleus 

 erythrophilous. Strasburger found that the small nuclei 

 of the cells formed in the pollen grains of gymnosperms 

 were kyanophilous, whether the cells were vegetative or 

 destined for generation ; but the nucleus of the pollen- 

 tube was more or less decidedly erythrophilous. The 

 second and larger portion of this " Beitrag" is devoted 

 to swarmspores, gametes, vegetable spermatozoids, and 

 the nature of fertilisation. W. B. H. 



Attires Mondes. By Amddee Guillemin. (Paris : 

 Georges Carrd, 1892.) 



Whether the author of this small volume thought that 

 the sequence of the subjects dealt with was really quite 

 unimportant, or whether no order at all was intended, 

 puzzled me considerably when glancing through these 

 pages for the first time. To be suddenly led off without 

 a word of warning into " L'infini dans le temps et dans 

 I'espace," and then to be as suddenly pulled back again 

 to a second chapter deahng with Sirius seems rather a 

 large oscillation to commence with. The same remarks 

 might apply to the next chapters, for they treat consecu- 

 tively of "The Cluster in Hercules," "StructureoftheVisible 

 Universe," " Movement in the Universe,'' and " The 

 Nebula of Orion, " followed up by chapters on " The Age 

 of Stars," and " The End of the Solar System. 



That the work is written by M. Guillemin is quite 

 sufficient guarantee that strict accuracy is throughout 

 adhered to 'Jhe book is one that can be picked 

 up at odd moments and a chapter or two read with 

 delight. The illustrations are excellent copies of lunar 

 and stellar photographs taken by the brothers Henry at 

 the Paris Observatory. W. J. L. 



Somt Lectures by the late Sir George E. Paget, K.C.B., 

 F./i.S. Edited, with Memoir, by Charles E. Paget. 

 (Cambridge : Macmillan and Bowes, 1893.) 



This volume will be cordially welcomed by the late Sir 

 George Paget's friends ; and members of the medical 

 profession, whether they knew him personally or not, will 

 find in it much that cannot fail to interest them. The 

 lectures deal with three subjects — the aetiology of typhoid 

 fever, alcohol as a cause of disease, and mental causes of 

 bodily disease. In dealing with each of these topics, the 

 author presents the results of prolonged and most careful 

 observation ; and it is impossible not to admire the direct- 

 ness, lucidity, and vigour with which his facts and con- 

 clusions are set forth. The memoir, by the editor, is a 

 short and attractive record of Sir George Paget's distin- 

 guished career, and its value is increased by the fact that 

 it is accompanied by an excellent portrait. 



LETTERS TO THE EDITOR. 



a The Editor does not hold himself responsible for opinions ex- 

 pressed by his coi-respondents. Neither can he undertake 

 to return, or to correspond with the writers oj, rejected 

 manuscripts intended for this or any other part of Nature. 

 No notice is taken of anonymous communications.] 



Origin of Lake Basins. 



We may all thank Mr. Alfred Wallace fur putting together so 

 concisely ihe main aiguments on which the glacial theory of the 

 origin ol all lake basins has had a wide acceptance. My time 



NO. I 22 I, VOL. 47] 



is just now so occupied with "earth movements" of another 

 kind that I am unable to marshal all the arguments on the other 

 side. But 1 shall try to put the main points as clearly as I 

 can. 



I accept Mr. Wallace's correction of the word "grinding "as 

 the best word to describe the action of glaciers. It is better 

 than either "digging up" or "scooping." Many men who 

 account for marine gravels on such places as Moel Trefan 

 mountain-top by the action of glaciers, w/kj/ conceive of glaciers 

 as capable of digging out and lifting up. But I agree with Mr. 

 Wallace that "grinding" down is the best expression for true 

 glacier action. This is the mode of action ; but what of the 

 cause oi \\\e motion which effects the grinding? Are we agreed 

 on this ? Mr. Wallace does not explain his view on this point. 

 I hold that the only cause of true glacier action is gravitation, 

 and that masses of ice will not move at all. or exert any grinding 

 action, except when impelled by gravity down gradients more 

 or less steep. Even if they do mount up some slopes, it is only 

 when they are violently pushed by other masses moving down 

 slopes from behind them. If this be true, then glaciers will not 

 tend to dig holes out of the flat bottoms of valleys. Mr. Wallace 

 says they will, if they are exceptionally thick. This is very 

 doubtful : and still more is it doubtful that they can dig holes 

 of a very peculiar character, such as is now proved to be the 

 character of Como and other lakes, with steep and sharp out- 

 lines, or with barriers left untouched. One single fact of this 

 kind, if well ascertained, is quite enough to upset a great theory, 

 because it may be sufficient to prove that at least some lake 

 basins cannot have been made by glaciers. And if some 

 have not, it is not certain that any have been made by glaciers 

 alone. 



The constant association of lake basins with glaciated 

 countries is Mr. Wallace's grand argument. But it is explicable 

 in the theory of earth movements quite as easily as on the 

 theory of glacial action. Glaciated countries are generally hilly, 

 or mountainous. If Mr. Wallace believes that all hills and 

 valleys are due to superficial sculpturing alone, of course his 

 argument is facilitated. But if hills and valle)S are even in any 

 measure due to earth movements — crumplings of the surface — 

 then the formation of lake basins is an inevitable necessity. 

 Every hollow must become a lake basin which has no natural 

 outlet except at a higher level than at its own bottom, ^'et if 

 there be such a thing as earth movements at all, it is in the 

 highest degree improbable that they should have failed in 

 numerous cases to occasion hollows in which water would 

 accumulate. 



Mr. Wallace's unbelief that any earth movements have taken 

 place so lately in geological time as the glacial age— say 100,000 

 years ago — is a declaration that does indeed astonish me. 1 

 can understand great doubt and difficulty as to the extent of 

 these movements!. But that they have taken place to some ex- 

 tent very lately indeed is, in my opinion, demonstiable in the 

 country in which I now write. There is one old sea beach on 

 the Island of Jura where the stones as left by the surf are as 

 bare of vegetation and as unaltered in forms which show surf 

 action, as if the ocean had beat upon it last year. And this sea 

 beach extends for milesat elevations varying from 120 to(I believe) 

 160 feet. If I am not mistaken, recent surveys of the great 

 Canadian and American lakes have proved that they lie in 

 hollows of crumpled and distorted land surfaces. The whole of 

 Mr. Wallace's theory on this subject seems to me to be out 

 of date. 1 he distribution of boulders in the Highlands can, in 

 my opinion, be accounted for in no other way than the transport 

 of masses of stone on floating ice. But putting aside altogether 

 this larger question, if a "great submergence," as one of the latest 

 events in the glacial epoch, smaller elevations of the land are 

 among the most certain of geological facts. But if so, we have 

 lake-basins in all hilly countries easily explained. Very often the 

 elevation of land to a very small extent indeed, if unequal, as it 

 is sure to be more or less, would immediately cause lakes 

 wherever a pre-existing valley had its lower end more tilted than 

 its upper end. The 120 feel which is represented on the coast 

 of Jura in this county is an elevation which would fill half of 

 our glens all over the county with lakes unless it was an elevation 

 perfectly equal along the whole of pre-existing contours. The 

 co-existence of lake-basins with hilly and glaciated countries, 

 therefore, admits of an easy txplanalion without attributing to 

 ice a kind of action which has never been proved to exist at all. 

 Hilly countries are ounipUd countries, and slight increases or 

 decreases of the same action must of necessity produce lakes. 



