February 15, 19 12] 



NATURE 



515 



the curves are in each case all but straight, and are nearly 

 parallel to the vertical. They show (i) that the skull of 

 the living Englishman, that is to say, of the Royal 

 Engineers, is a little narrower than that of the seventeenth- 

 century Londoner, the difference being greatest across the 

 ears, and that, in like manner, the skull of the Batetelu 

 Negro is a little broader than that of the Negro from 

 Fernando Vas. In both cases the general similarity, or 

 identity of type, between the two skulls under comparison 

 is clearly brought out. 



Lastly, we may use the method to compare the left side 

 of the skull with the right. And so we find (Fig. 5) that 



VIO 



uo 



100 



90 



Fig. 5. 



in the English skull there is approximate identity through- 

 out most of the section, the left side being narrower in the 

 upper portion only ; in the Negro (Fernando Vas) the left 

 side is throughout inferior, while the Cro-magnon skull is 

 markedly unsymmetrical, the left side being the narrower 

 below, but expanded or flattened above in a striking degree. 

 January 27. D'Arcy W. Thompson. 



Microscope Stands. 



The correspondence which has ensued on the interesting^ 

 article on the above subject which appeared in Nature of 

 December 21, 191 1, has afforded much material for reflec- 

 tion. There must be a best possible design for a micro- 

 scope stand, but it is evident that the one required by the 

 ■expert amateur is different from that which is acceptable 

 and advantageous to the professional in the laboratory. 

 The former demands, and can wif.i advantage utilise, 

 many refinements that never appeal to the latter. The 

 best English microscopes undoubtedly supply the needs of 

 the expert — that appears to be admitted — and assuming 

 that the design of the Continental instrument is preferred 

 in the laboratory, it might be that the worker would 

 derive fuller benefit from his microscope if only some 

 additional conveniences were at his disposal and he knew 

 'W to use them. 



"^o far, the correspondence has been contributed by 

 perienced technical microscopists ; but the views of the 

 lier side would be welcome and informing. 

 To revert to the article in question, no one who has 

 id the use of a centring substage would be disposed to 

 ' cept a centring adjustment to the nosepiece in prefer- 



NO. 2207, VOL. 88] 



ence. It is stated that the latter adjustment is provided 

 in the Continental models, but I am unable to find a 

 centring nosepiece listed or described in either of the cata- 

 logues of the two leading German manufacturers of micro- 

 scopes, excepting only in connection with petrological 

 microscopes. Some centring device is admitted to be 

 necessary, and continual working with condensers having 

 large aplanatic cones soon reveals the necessity for the 

 centring substage. 



It is suggested that the correction collar fitted to 

 objectives is superior to the rackwork draw-tube for 

 adjusting for varying thicknesses of cover glasses. This 

 is quite correct ; but probably not more than i per cent. 

 of the objectives that are sold have correction collars, and 

 in consequence of the perfection in which even students' 

 lenses are now made, the sensitiveness to thickness of 

 cover glass necessitates careful adjustment by variation of 

 tube length. There is another important feature of the 

 mechanical draw-tube, and that is it gives a maximum 

 and a minimum body length which permits of the use of 

 any objective, whether corrected for the short or the long 

 tube, though this is subsidiary. 



As to the standardisation of the substage fittings, a 

 definite size is given by the Royal Microscopical Society, 

 and if this is adhered to there can be very little trouble 

 about interchanging. It has to be remembered that one- 

 thousandth of an inch in the diameter of a tube makes all 

 the difference between a tight and a slack fitting ; tube 

 fittings are particularly liable to variation in consequence 

 of slight bending. Objectives do not always interchange, 

 though all are ostensibly made to the standard size ; but 

 the alterations needed are exceedingly slight, and the 

 differences in the substage apparatus of standard size are 

 rarely such as cannot be quickly corrected. It seems 

 reasonable to assume that if it be good to have a standard 

 size for eyepieces and objectives, it is equally advantageous 

 to have one for the substage. The English makers work 

 loyally to the one standard of the Royal Microscopical 

 Society, while the Continental makers each have two or 

 three different ones. 



At the bottom of all questions relating to the use of the 

 microscope is the urgent necessity for systematic teaching 

 in the elementary technique of the instrument. It is not 

 unusual to meet men of eminence who are constantly 

 working with microscopes who do not even know that a 

 substage condenser requires to be focussed. How is it 

 possible that the refinements of the English microscope 

 can appeal to their students? F.R.M.S. 



The Inheritance of Mental Characters. 



To the discussion on the question of the inheritance of 

 mental characters [y. Nature,. December 28, 1911, p. 278) 

 as one who takes an interest in the subject, but can 

 lay no claim to having expressly studied it, I should be 

 glad to be allowed to contribute a few experiences 



In a girls' primary school the writer knew a child who 

 from the age of five until eleven (when her education was 

 complete) was, owing to her daring athletic feats, a 

 torture to her teachers. They were in a perpetual worry 

 lest she should break her bones or her neck. Punishnient 

 —and it was pretty liberal— was of no use; when their 

 backs were turned she was at it again. They— and some 

 of them were old teachers— had never met one like her. 

 The other children, about 150 in number, were normal. 

 This one had no peculiar environment, no special oppor- 

 tunities. But her father was a professional showman. 

 She like the Greek CEdipus. had never seen him. nor 

 did her mother ever speak of him. He had been raised 

 on a small farm. His brothers were commonplace work- 

 men. The teachers were unaware of the showman 

 parentage. Some few of us knew, and watched with 

 interest the developments. ,,•,-. ^< „« 



This case seems an instance of tb. inheritance of an 



acquired taste. , , ,,^1.* 



True it, no more than any case that can be brought 

 forward is not bevond question; for just possibly in the 

 child— as very likely previously in the father— the mere 

 abnormal potentiality was there. This ,Pe'.h«P«. ^f «»« 

 accident revealed to her. We always like to do what we 



