October 13, 1923] 



NATURE 



539 



during the development of the human embryo, taking 

 as examples the development of the eye, of young 

 nerve-cells, of muscular adaptations. In the adult 

 human leg the'peroneus tertius is separate in 90 per 

 cent, of cases, having thus an advantageous position 

 for the performance of its function in walking. In 

 the anthropoid apes this muscle is quite unseparated 

 "rom the long extensors of the toes. In the developing 

 luman foetus the rudiment of the peroneus tertius 

 sparates from the long extensors with which it was 

 Originally continuous. To most biologists this would 

 )e a typical case of recapitulation. 

 Sir Arthur Keith says he agrees with Huxley that 

 lere are no grounds for believing that the behaviour 

 )f embryonic muscle cells is in any way influenced 

 >y experiences gained by adult muscle fibres. He 

 then makes the statement that " The evolutionary 

 lachinery lies in the behaviour of the embryonic 

 luscle cells or myoblasts," which to me, as it stands, 

 quite unintelligible. The behaviour of the em- 

 jryonic muscle cells can explain nothing but the 

 lode in which the adult structure is developed, 

 such behaviour begins and ends with the individual 

 jrganism, and cannot possibly contain any evolu- 

 ionary machinery. It is merely one detail of the 

 )mplicated embryological changes by which the 

 idult structure is developed. In relation to evolution 

 the question is how are we to explain the fact that 

 the " behaviour of the embryonic cells " is different 

 the human foetus from what it is in the anthropoid 

 ipes, which presumably resemble the ancestral 

 jndition ? On this question Sir Arthur Keith says 

 lothing, except the assertion quoted of his agreement 

 Vith Huxley. 



In another part of his lecture Sir Arthur Keith 

 iiscusses the action of hormones in the course of 

 jntogeny in co-ordinating the development of 

 lifferent parts and tissues. He concludes that more 

 )mplete knowledge " will reveal in full the true nature 

 jf the machinery which underlies the production of 

 Structural adaptations which occur in everv part of 

 "le animal body in every stage of its evolution." 

 [ere, again, he is confounding the evolution or origin 

 )f the adaptations with their mere development in 

 "le individual. 



Nevertheless, Sir Arthur, while denying the in- 

 iuence of external influences in human evolution, 

 Idmits the heredity of " acquired characters " and 

 jven injuries in certain cases. He states that 

 imarckism cannot explain the characters which 

 iifierentiate one racial type of modern man from 

 lother. On this last point I am entirely in agree- 

 ment with him, for Lamarckism is a theory of the 

 solution of adaptive characters, and racial characters 

 )f man are for the most part not adaptive. 

 I should like in conclusion to contrast two passages 

 Sir Arthur Keith's lecture. He writes, " Nothing 

 better known than that, if a bone of a rickety child 

 ends under the weight of the body, the bone cells 

 ^ing in its concavity will proliferate and build a 

 ^uttress to strengthen the shaft." The bone cells 

 'jreact to fulfil an end necessary for the occasion." 

 "lis seems to me quite inconsistent with the state- 

 lent, " there are no grounds for believing that the 

 jhaviour of embryonic cells is in any way influenced 

 >y experiences gained by adult muscle fibres." The 

 first of these two passages admits the reaction of the 

 tissues of the body to external stimuli, while the 

 second passage and the whole tendency of the lecture 

 apparently denies the occurrence of such reaction. 



Chiswick, \V.4, 



September 11. 



NO. 281 5, VOL. I 12] 



J. T. Cunningham. 



Curious Spherical Masses in Ashdown Sands. 



]Mr. Harry E. Burns, of Crowborough, this spring 

 informed me of some remarkable spherical masses of 

 sandstone in the Ashdown Sands at High Hurst Wood 

 Quarry, and was good enough later to supply one about 

 10 inches in diameter to our Museum. He suggested 

 that they might be sand casts of reptilian eggs like 

 that of the Iguanodon. They consist of fine-grained 

 nearly white stone— much of the iron having been 

 leached out. I expected but failed entirely to find on 

 section any pan or stains of limonite such as in the 

 well-known balls of Folkestone Sands. 



Recently I have visited the quarry with Mr. Burns, 

 and was able to see a ball 30 inches in diameter in 

 position. We were told they are confined to an upper 

 bed about 14 feet thick, and vary in size from 10 to 30 

 inches in diameter. We could discover no evidence 



Fig. I. 



of a foreign body or of concretionary growth, although 

 such growths are not rare in the Wealden Sandstones 

 — often, too, in a decalcified condition. Those at 

 Crowborough are found loose in a narrow cavity, and 

 the stone appears identical in colour, etc., with that 

 of the surroimding bed. The adjacent stone for a 

 few inches is shattered — due, I suppose, to the press- 

 ure of overlying beds against the unyielding sphere, 

 while the narrow clefts are filled with clay, doubtless 

 washed there from the once overlying Wadhurst Clay. 

 Strangely enough, some of these balls have been used 

 as ornaments at the tops of wooden gate - posts ! 

 During the forty-five years I have lived in the neigh- 

 bourhood I have not met such masses before, and find 

 them difficult to explain. The photograph (Fig. t) 

 shows a group of these stones taken by Mr. Burns, who 

 kindly allows me to use it. Geo. Abbott. 



2 Rusthall Park, Tunbridge Wells, 

 September 10. 



Stereoisomerism among Derivatives of Diphenyl. 



Dr. Turner's remarks (Nature, September 22, 

 p. 439) appear to have been made without his having 

 seen my letter of some eighteen months ago (Nature, 

 May 6, 1922, p. 581), which was concerned with 

 the importance of stereoisomerism among diphenyl 

 derivatives in relation to Sir William Bragg's conclu- 

 sions as to the molecular structure of benzene in 

 the crystal. At that time, reasons for reviving the 

 Dewar para-linkage formula for benzene had not been 

 published (Ingold, Trans. Chem. Soc, 1922, 1143), 

 but since this bridged formula " is stereochemically 



