?>4 



NATURE 



[May 14. 1Q03 



numbers of gametes G, bearing albino with pink-eye, and G' 

 bearing colour with pink-eye. Consequently from GG'x 

 GG' we expect and obtain GG+aGG'+G'G' ; and from 

 GG'xG equal numbers (approximately) of GG and GG'. 

 So far, GG are pink-eyed albinos ; GG' are dark-eyed with 

 some colour in coat; G'G' are pink-eyed, but with some 

 colour in coat. 



If we do not consider what particular colour GG' and 

 G'G' will have, we may treat all gametes G' as identical. 

 But after crossing with albino such a. condition would be 

 unusual. The colour brought in by the original G' is gener- 

 ally in part resolved, and various sorts of G' gametes are 

 formed, viz. aG', bG', cG', abcG', &x. Therefore when the 

 hybrids breed together there will be GG' zygotes of several 

 colours, viz. G.aG', G.bG', G.cG', &c. ; also G'G' zygotes 

 of several colours, viz. aG'.aG', aG'.bG', &c. Each com- 

 bination will have its appropriate colour and frequency, 

 though (if the regularity be maintained) all GG' will have 

 dark eyes and some colour, and all G'G' pink eyes and 

 some colour. But as the hybrid produces G gametes equal 

 in number to the various G' gametes collectively, GG' x GG' 

 will give on an average one albino in four offspring (ex- 

 periment gave nine in thirty-seven) ; and there is no ques- 

 tion of one in nine. We are only concerned with one hypo- 

 thesis (that I have set forth in " Mendel's Principles of 

 Heredity," p. 29), and with this hypothesis the published 

 facts are in admirable agreement. 



Heterogeneous offspring from crossing two seemingly 

 pure races may seem to Prof. Weldon an " amazing " 

 phenomenon, but it is one with which the breeder early 

 becomes familiar. Even albinos need not be pure or their 

 gametes homogeneous in characters other than albinism. 



Grantchester, Cambridge, May i. W. Bateson. 



Mr. Bateson reconciles his statements in Nature of 

 March 19 and April 23 by explaining that in his first letter, 

 when he describes certain mice as of constitution G'G', he 

 is deliberately denoting a whole series of different gametes 

 by the same name. 



The suggested heterogeneity among the gametes of pure 

 albinos is now said to affect characters other than albinism, 

 and is therefore wholly irrelevant. The avowed vagueness 

 in the use of the symbol G' makes it uncertain whether 

 the fawn-and-white mice are now supposed to produce 

 gametes of different character (with regard to coat-colour 

 and eye-colour) or not. If the gametes of all the fawn-and- 

 white mice used are similar, then all hybrids between these 

 and albino mice are of similar constitution, and the fact 

 that some are yellow, some grey, and some black is left 

 unaccounted for. If the fawn-aad-white mice produce even 

 three kinds of gametes, G',, G'^ and G'3, then on crossing 

 with albinos the hybrids GG',, GG'j and GG'3 may be of 

 ■different coat-colour ; but since the fawn-and-white mice 

 always breed true to colour when paired inter se, it surely 

 follows that the combinations G'^G'i, G'fi'^, G'fi'^, &c., 

 which arise from such unions (some homozygotes and some 

 heterozygotes) give rise to mice of similar colour. It is 

 this consequence of heterogeneity in a pure-breeding race 

 which seems to me amazing. 



In assuming that coat-colour is resolved into simpler 

 elements when hybrids form their gametes, Mr. Bateson 

 follows Mendel ; but in such cases Mendel assumes that 

 all the various kinds of gametes, produced by the hybrid, 

 occur with equal frequency, and Mr. Bateson has elsewhere 

 attempted to bring this assumption into relation with the 

 phenomena of cell-division (" Mendel's Principles of 

 Heredity," p. 30). In trying to fit Mr. Darbishire's facts 

 by a Mendelian formula, Mr. Bateson abandons this hypo- 

 thesis ; he now says that a hybrid mouse produces (i) a 

 series of different kinds of colour-bearing gametes, and (2) 

 a number of gametes bearing the characters white coat and 

 pink eye, equal to the sum of all the other kinds of gametes 

 together. This departure from Mendel's hypothesis is 

 masked in Mr. Bateson 's first letter by the simple device 

 of calling the whole series of different colour-bearing 

 gametes by the same name G'. 



Mendel's own view of the way in which compound 

 characters behave gives a maximum possibility of one pure 



recessive albino among sixteen offspring of hybrids ; a non- 

 Mendelian view, lately put forward by Mr. Bateson in 

 another case of colout-resolution {Proc. Camb. Phil. Soc, 

 vol. xii. p. 52), gives a maximum of one in nine ; the view 

 he now suggests for mice gives one in four. By modifying 

 first one and then another of Mendel's statements, his name 

 is made to shelter almost any hypothesis, and almost any 

 experimental test is evaded. 



In the next number of Biometrika Mr. Darbishire will 

 publish a series of new results, which have an important 

 bearing on the application of Mendel's " principles " to hi': 

 mice. Until these new facts are available, I do not think 

 further discussion will be profitable, and therefore I do noi 

 propose to continue this correspondence. 



Oxford, May 6. W. F. R. Weldon. 



[This correspondence must now cease. — Ed.] 



INTERNATIONAL METEOROLOGICAL 

 COMMITTEE. 



THE International Meteorological Committee ap- 

 pointed by the Paris Congress of 1896 in suc- 

 cession to those appointed by previous congresses, 

 commencing with the Vienna Congress of 1873, will 

 meet this year at Southport during the session of the 

 British Association, September 9 to 16. The com- 

 mittee held a single meeting in the room at the top 

 of the Eiffel Tower in 1900; its last normal session 

 was at St. Petersburg in 1899. It has not met in 

 England for twenty-six years. The original " per- 

 manent " committee was appointed by the Vienna Con- 

 gress in 1873, and consisted of six members under the 

 presidency of Buys Ballot; its successor now numbers 

 seventeen members, representing a large number of 

 the official meteorological organisations of the world. 

 Prof. Mascart, of the Bureau Central M^t^orologique 

 of France, is president, and Prof. H. H. Hilde- 

 brandsson, of the Royal Observatory of Upsala, is 

 secretary, having been elected to that ofifice on 

 the resignation of Mr. Scott, who was secre- 

 tary from 1874 (the Utrecht meeting) until the 

 close of 1899. The other members are Prof, 

 von Bezold (German Empire), Prof. Billwiller (Switzer- 

 land), Captain Chaves (Azores, Portugal), VV. Davis 

 (Argentine), Sir J. Eliot, K.C.I. E. (India), Prof. S. 

 Hepites (Roumania), Prof. H. Mohn (Norway), Prof. 

 Willis L. Moore (United States), Prof. L. Palazzo 

 (Italy), Prof. Paulsen (Denmark), Prof. J. M. Pernter 

 (Austria), Mr. H. C. Russell, C.M.G. (Australia), 

 General Rykatcheff (Russia), Mr. W. N. Shaw 

 (Great Britain), and Prof. H. Snellen (Holland). 



The functions of the committee are to discuss meteor- 

 ological questions of international interest and formu- 

 late proposals for international cooperation in connec- 

 tion therewith. The deliberations have an official 

 character in virtue of the committee being ap- 

 pointed by a congress of representatives dele- 

 gated in response to an official invitation of one or 

 other of the European Governments, but the committee 

 has no executive authority. It has been the practice 

 for the committee to appoint from time to time various 

 " commissions " or subcommittees to prepare reports 

 upon questions that require preHmlnary discussion. 

 The members of these subcommittees are not neces- 

 sarily members of the International comrnlttee. They 

 meet from time to time on the invitation of their 

 respective chalrrrien, and opportunity Is often taken of 

 the occasion of the meeting of a subcommittee to 

 obtain more general discussion by Inviting other per- 

 sons Interested In the special subjects to take part in 

 the proceedings, and sometimes to become members 

 of the subcommittee. There are at present five sub- 

 committees, constituted as follows : — 



NO. 1750, VOL. 68] 



