324 



NATURE 



[November i8, 191 



fishery investigations consist of an account, by Prof. 

 Meek, of the migrations of the grey gurnard. The 

 eggs and pelagic larvae of this fish drift passively in- 

 shore towards the Northumberland coast with the 

 general set of the current, and with increasing size 

 they then move offshore. The migrations are corre- 

 lated with the direction of the movements of the water, 

 but it is more probable that the seasonal variation of 

 temperature is a more importfint factor. Study of the 

 general direction and the annual shifting of the 

 isotherms would bring out this relationship. Prof. 

 Meek also writes on the migrations of the dab. Mr. 

 Storrow has accounts of the age and rate of growth of 

 herrings and pilchards taken off the coast of 

 Northumberland. The herring investigations form 

 part of the general scheme of biometric research 

 carried on by the Board of Agriculture and Fisheries, 

 but only data referring to the age of the fishes, as 

 determined by a study of the scale-markings, are dis- 

 cussed in this report. 



Mr. J. H. Paul contributes an interesting account 

 of the phenomena of autotomy in the Decapod Crus- 

 tacea, with reference mainly to the lobster and crab. 

 It is well known that injury to, or forcible retention 

 of, a limb leads to the breaking of the latter. Escape 

 is suggested as the object of autotomy on the part of 

 the lobster, but more often a limb is thrown off by 

 the crab as the result of injury and as a means of 

 arresting haemorrhage. Mr. Paul has studied the 

 anatomy of the parts affected, and has also made 

 experiments on the actions of the muscles and nerves 

 involved. His figures are rather difficult to follow, 

 but he shows that autotomy of a limb always occurs 

 by a fracture in the exoskeleton running partially 

 round a "breaking-groove" in the third segment of 

 the limb. The fracture is a pluri-segmental reflex, 

 and it is effected as the result of antagonistic muscles. 

 It occurs, in the lobster, in about four seconds after 

 nocuous stimulation. J. J. 



JAMES GEIKIE'S RESEARCHES IN 

 GLACIAL GEOLOGY. 



AT the meeting of the Royal Society of Edinburgh 

 on November i. Dr. J. Home, F.R.S., president 

 of the society, delivered an address on "The Influence 

 of James Geikie's Researches on the Development of 

 Glacial Geology." At the outset reference was made 

 to the appointment by the council of a committee 

 to conduct investigations in connection with sub- 

 marines, aeroplanes, asphyxiating gas, and high ex- 

 plosives. The experimental work had been carried 

 out with the financial aid of an anonymous donor, 

 whose generosity and patriotic spirit had been highly 

 appreciated by the council. 



The subject of the address had been chosen because 

 James Geikie's researches in Glacial geology were 

 the most striking feature in his scientific career. They 

 stimulated inquiry and at the same time aroused 

 keen opposition. Brief allusion was made to the 

 state of research in this country when he began his 

 investigations, how glacial phenomena were errone- 

 ously attributed to the action of icebergs, and how 

 the clue to the correct interpretation was furnished by 

 Agassiz during his visit to Scotland in 1840. From 

 the evidence which he obtained in the midland valley 

 and in the Highlands he inferred that glaciers for- 

 merly existed there in post-Tertiary time. 



The land-ice theory of Agassiz was adopted and 

 confirmed by Buckland, Ramsay, Archibald Geikie. 

 and Jamieson, but nearly a quarter of a century elapsed 

 before the accuracy of this interpretation was ade- 

 quately recognised. As James Geikie's field work in 

 the Geological Survey proceeded he evolved certain 



NO. 2403, VOL. 96] 



ideas regarding changes of climate in Pleistocene 

 time, based on the succession of boulder-clays with 

 intercalations of sand, gravel, and peat, and on the 

 cave deposits and Paleeolithic gravels in the south of 

 England, which he afterwards published in 1874 in 

 his volume "The Great Ice Age." He therein gave 

 an account of the Glacial and post-Glacial deposits 

 of the United Kingdom, Scandinavia, Switzerland, 

 and North America. Through the whole description 

 runs the ])rinciple, which , he believed to be funda- 

 mental, that the Glacial epoch was not one continuous 

 age of ice, but consisted of a series of cold and genial 

 periods. In his discussion of the question of the age 

 of the Palaeolithic gravels and cave deposits in the 

 south of England, he opposed the view held by many 

 that they were post-Glacial, and referred them to 

 inter-Glacial or pre-Glacial times. As regards the 

 commingling of northern and southern mammals in 

 these deposits, he combated the theory that this 

 assemblage was due to seasonal migrations. He con- 

 tended that the phenomena pointed to changes of 

 climate. 



These were the essential points in James Geikie's 

 teaching which he never discarded. They encountered 

 persistent opposition from the monoglacialists, who 

 maintain the unity of the Glacial epoch, and ascribe 

 the intercalated deposits to local movements of reces- 

 sion of the ice within one period of glaciation. Atten- 

 tion was next directed to his elaborate classification 

 of European deposits, comprising six Glacial epochs 

 separated by five genial periods. It was suggested 

 that the fifth and sixth cold phases were not sufficiently 

 severe to entitle them to be ranked as distinct Glacial 

 epochs. If we eliminate the two last cold phases, his 

 classification agrees with that of Penck and Bruckner 

 in the Alps. The evidence furnished bv the Eemian 

 clays, the Hotting breccia, the Diirnte'n lignite, the 

 Don Valley section near Toronto regarding climatic 

 changes in inter-Glacial time was reviewed. The 

 opinion was expressed that sufiicient evidence had 

 been obtained to establish the general principle of 

 oscillations of climate in the Glacial epoch, though 

 the^ number of inter-Glacial periods may remain a 

 subject of controversy. 



ZOOLOGY AT THE BRITISH 

 ASSOCIATION. 

 AT its first meeting Section D heard with profound 

 -^~^ regret that owing to serious illness the President 

 of the Section, Prof. E. A. Minchin, was unable to be 

 present. The presidential address, his last work, was 

 read by Mr. Heron-Allen, and a telegram was then 

 sent to Prof. Minchin conveying to him the sympathy 

 of the section and thanking'^him for his able address. 

 The following is a summary of the communicatiohs 

 presented to the Section. 



The Relation of Chromosomes to Heredity. 

 In opening a discussion on this subject Prof. 

 MacBride said that there seemed to be no escape from 

 the position that the chromatin, viewed as a whole, is 

 the bearer of the hereditary tendencies, for the in- 

 fluence of the father in determining the character of 

 the offspring is as potent as that of the mother. The 

 head of the spermatozoon, which is the only part of 

 the father which enters into the constitution of the 

 progeny, appears to consist practically exclusively of 

 chromatin. The formation of the organs of an 

 embryo is known in many cases to be due to sub- 

 stances localised in the cytoplasm, but the formation 

 of these substances can be shown to be due tc 

 chromatic emission from the nucleus of the unripe 

 egg. Prof. MacBride then considered the difficult 



