December 15, 1923] 



NATURE 



86' 



the " reaction of the animal as a whole " explains the 

 fact. 



Prof. MacBride has a photograph of an operated 

 Ciona and a noirmal one side by side. What is the 

 proportional length of the oral siphon in a " normal " 

 Ciona, and what was that length in the operated 

 siphon before operation and after regeneration ? 



J. T. Cunningham. 

 East London College, 

 Mile End Road, London, E., 

 November 24. 



Mrs. Hertha Ayrton. 



It must be a matter of pain and surprise to many 

 readers of Nature that Professor Armstrong should 

 have written such an article as that which appears on 

 p. 800 of the issue of December i. 



I was privileged to know, with the intimacy which 

 is only possible to a doctor, both Prof, and Mrs. Ayrton 

 during many years. He was my patient until he 

 died — prematurely in one sense, but in another he 

 lived long, and accomplished more than many men 

 who live to extreme old age. It seems almost sacri- 

 lege to speak of their married life, or of the perfect 

 sympathy and companionship which distinguished 

 it ; it is difficult to understand how any one professing 

 to have been their friend could suggest that they 

 were " an ill-assorted couple." 



No woman could have nursed her husband with 

 more untiring, unselfish, and tender devotion. Of 

 their scientific work I leave others to speak ; there 

 will surely be many who will vindicate their memory 

 in this respect. But as an old and intimate friend I 

 am well qualified^ to protest against the heartless 

 comments upon the private life of a very noble woman 

 of whose living presence we are so recently bereaved. 

 The Latin races respect their dead friends with an 

 emotion we can at least respect. The Day of the 

 Dead, held in reverence probably surpassing any- 

 thing in the Christian ritual, has scarcely passed this 

 year, and yet Prof. Armstrong can write such an 

 article upon his dead friends. Surely for the rest of 

 his life he will regret not having declined that 

 " appeal " for an obituary notice. H. H. Mills. 

 21 St. Mary Abbot's Terrace, 

 Kensington, W.14. 

 December 3. 



The only comment I can possibly make on the 

 above is, that the writer must be strangely lacking in 

 .sense of humour. 



When I used to tell my friends that they were " ill- 



issorted," knowing this full well and knowing me, 



they did but smile. As did Mrs. Ayrton — when, to 



terminate one of our fruitless discussions on the 



> oman as man, I sometimes said : " We will admit 



')U are 'up to us' (apart from being yourselves), 



hen you are regularly engaged as chefs and produce 



;ie to go down to posterity with Soyer." 



May I here note the need of a correction in my 



• irticle — the insertion oi the accent over the first e in 



NIelisande ? So beautiful a name should not be reft 



it the least shade ot its charm. 



Henry E. Armstrong. 



Zoological Bibliography. 



Lest it should be assumed from my friend Dr. 

 Bather's communication to Nature of December i, 

 page 794, that my letter was premature, let me state 

 that my communication was forwarded to Nature at 

 the express wish of the Conference of Delegates and 



NO. 2824, VOL. 1 I 2 j 



with the concurrence of the various officers of the 

 British Association, who were present at the time. 



There is no misunderstanding whatever as to the 

 wishes of the representatives of the numerous 

 scientific societies present in regard to the size of 

 publications, and if Dr. Bather will consult such a 

 publication as CoUins's " Authors' and Printers' 

 Dictionarv," issued by the Oxford University Press, 

 he will find that demy-octavo is slightly less than the 

 measurements he gives, namely, 8| x 5^ in., and this 

 is the size which that particular committee re- 

 commends to all societies publishing annual reports, 

 etc. T. Sheppard. 



The Municipal Museums, Hull. 



Micelles and Colloidal Ions. 



Mr. W. B. Hardy in his letter to Nature of 

 October 13, p. 537, entitled "The Micelle — A Ques- 

 tion of Notation," advocates the conception of the 

 colloidal ion and postulates that the ideas of other 

 workers coincide with his own, so that merely a 

 question of nomenclature is involved ; nevertheless, 

 in his opinion, it is positively wrong to refer to a 

 colloidal ion as a micelle. 



It will be shown in a paper by Miss M. E. Laing 

 which we hope to publish in an early number of the 

 Journal of Physical Chemistry, that all movement in 

 an electric field can be summed up in a single formula 

 which applies equally to ions, diaphragms, gels, sus- 

 pensions, micelles, etc., and governs the movement of 

 any such charged constituent relative to the solvent. 

 The experimental evidence shows that there is a 

 gradual transition from uncharged or isoelectric 

 colloidal particles, through those which are very 

 slightly charged, such as the neutral micelle in soap 

 solution or the particles in a gold sol, to those which 

 are much more highly charged, like the ionic micelle 

 of soaps, and then to the true ions which are fully 

 charged. 



Now comes the question of nomenclature. There 

 is no question as to the fully charged ion where this 

 coincides with the chemical unit. In soap solutions, 

 however, there is a sharp distinction between the 

 behaviour of the single crystalloidal molecules or ions 

 and their respective aggregations, the neutral and 

 ionic micelles, which, for example, can be held back 

 by an ultrafilter. 



It would seem as repugnant to designate an aggre- 

 gate of soap ions containing substantial proportions 

 of undissociated soap and of solvent a " colloidal ion " 

 as it would be to call aggregates of hydrated neutral 

 soap, which are probably the structural basis of soap 

 jellies, " colloidal molecules," although one is as 

 logical as the other. I have called each of these 

 aggregates a micelle, and have described their elec- 

 trical condition by adding the prefixes neutral and 

 ionic respectively. The term micelle is customarily 

 employed in a similar sense in contemporary French 

 and Gierman science. James W. McBain. 



Dept. of Physical Chemistry, 

 University of Bristol. 



Biography of Richard A. Proctor. 



We are at present engaged in the preparation of a 

 " Memoir " of the late Richard A. Proctor, and to 

 assist us in our work we should be deeply grateful for 

 the loan of any letters which readers of Nature may 

 have received from him. Wc will carefully preserve 

 the letters and return them as soon as possible. 



S. D. Proctor-Smyth. 

 Mary Proctor. 

 9 Orchard Road, .Vltrincham, Cheshire, 

 December 3. 



2 A 2 



