i88 



NATURE 



[January 28, 19 15 



useful addition to a subject the literature of which 

 is not extensive. 



In dealing with the more theoretical matters 

 concerning- the laws of expansion and compression 

 of g-ases the author is not so fortunate, and there 

 are a number of loose and careless statements. 

 Thus on p. 160 we find Boyle's law stated as 

 follows : At constant temperature the volume of 

 gas is proportional to the absolute pressure. The 

 author is not unaware of the fact that the volume 

 is inversely proportional to the absolute pressure, 

 but this and other similar careless statements of 

 facts mar an otherwise good and useful volume, 

 and call for a thorough revision for the second 

 edition. 



LETTERS TO THE EDITOR. 



[The Editor does not hold himself responsible for 

 opinions expressed by his correspondents. Neither 

 can he undertake to return, or to correspond with 

 the writers of, rejected manuscripts intended for 

 this or any other part of Nature. No notice is 

 taken of anonymous communications.'] 



Electrical Notation. 



Sir Joseph Larmor's letter in Nature of January 

 21 (p. 561) reminds me that I have long wished to 

 protest against the misuse of alphabetical symbols to 

 designate the names of units. The word ohm, for 

 instance, ought not to be abbreviated to w ; and the 

 apparently authoritative suggestion now made that 

 other names shall be written in the same sort of 

 unreadable and worrving shorthand is essentialh, 

 though not superficially, illiterate as well as utterly 

 unmathematical. 



The naming of units has been conspicuously useful ; 

 the consumption of much-needed and already over- 

 worked symbols as substitutes for names is a 

 wasteful practice which should be resisted among 

 physicists, and be only tolerated in microscopy for 

 purely biological use. 



Oliver Lodge. 



University of Birmingham, January 23. 



Mendelism in the Seventeenth Century. 



The Mendelian revival of breeding has brought to 

 light many interesting facts concerning the inheritance 

 of coat-colour in rabbits. From the work of Hurst, Cas- 

 tle, Punnett, and others, it is now known that when the 

 wild "grey " or "agouti " rabbit is mated with white, 

 black, or " blue " specimens, the offspring produced all 

 display the colour of their wild parent. Although this 

 is doubtless well known at the present day, it is, I 

 believe, not generally known that these facts had 

 been ascertained by rabbit-fanciers in Holland in the 

 seventeenth century, and were put on record b}' the 

 illustrious Leeuwenhoek in 1683. 



In a letter from Leeuwenhoek to the Royal Society, 

 addressed to Sir Christopher Wren, and dated July 26, 

 1683, the following remarkable passage occurs : — 



'■ Multi nostratium civium alunt cuniculos, cum ad 

 voluptatem, turn ob lucrum : suntque hi cuniculi 

 plerumque magni atque albi, auribus praelongis 

 donati, quod pulchritudinis loco ducunt. Ut vero hi 

 cuniculi in lucem edant pullos grisei sive cinerei 

 coloris, qualis est sylvestrium, utque pro his possint 

 verno tempore vendi, foemellae albae marem griseum 

 ac sylvestrem ex tumulis arenarum petitum, ubi 

 omnes grisei coloris sunt, sociant : atque tales 

 masculos intense griseos committunt non tantum cum 



albis, sed & versicoloribus, nigris, caeruleis foemellis : 

 Ex quibus tamen quicquid procreatur, colorem patris 

 refert ; ut nunquam etiani observatus sit ullus ex tali 

 jugatione productus cuniculus, qui fuerit capillo albo, 

 aut alio quain griseo. Praeterea tales nunquam 

 attingunt niagnitudineni matris, neque aures acquirunt 

 praelongas, neque pro matris natura plane cicurantur 

 ac mansuefiunt, sed rctinent semper aliquid ferocioris 

 ferinaeque naturae ac indolis." 



The letter will be found in the so-called " Opera 

 Omnia" of Leeuwenhoek (Lugd. Batav., 4 vols., 

 1722). Owing to the confusing arrangement and 

 pagination in this work^ — which consists of a number 

 of separate sections, published at different dates, each 

 with its own pagination — it is not eas}- to give an 

 exact reference to a particular passage. In the copy 

 of the " Opera Omnia " which I have consulted, the 

 letter occurs on p. 49 (first pagination) of vol i. 

 ("Anatomia et Contempiationes "), under the title, 

 " De generatione Ranarum," etc. The passage in 

 question begins at the foot of the following p. 53. 



I may add that the letter is not to be found in 

 Samuel Hoole's English edition of Leeuwenhoek's 

 "Select Works" (London, 2 vols., 1798, 1807). This 

 translator expurgated all Leeuwenhoek's letters deal- 

 ing with spermatozoa. He calls them " Disquisitions 

 I of a peculiar kind, which to many Readers might be 

 offensive." 



Eeeling some doubt as to the colour or marking 

 which ''versicolor'' is intended to denote, I compared 

 the Latin letter with an English version which was 

 published under the title, "An Abstract of a Letter 

 from Mr. Anthony Leeuwenhoeck of Delft about 

 Generation by an Animalcule of the Male Seed, etc.."" 

 in the Philosophical Transactions of the Royal Societ\ 

 vol. xiii. (xii.), p. 347, 1683. Both Latin and English 

 versions are translations from the Dutch : for Leeu- 

 wenhoek could write no language but his own. In 

 the English version, which is somewhat differently 

 worded from the Latin, the words " versicoloribus, 

 nigris, caeruleis " are rendered " Blew, Black, and 

 Pyed." " Versicolor " evidently denotes some kind ot 

 piebald marking ; though it probably does not mean- 

 as one might perhaps conclude — the modern " Dutch 

 pattern. This, Prof. Punnett tells me, is of com- 

 paratively recent introduction, and has superseded an 

 earlier or "original Dutch" marking which "has less 

 white and has practically dropped out of the fancy." 



It is clear from Leeuwenhoek's words that the 

 Dutch rabbit-fanciers had, as early as 1683. discovered 

 that the offspring produced by mating wild " grey " 

 buck rabbits with tame long-eared white, black, blue, 

 or piebald does, are always exclusively grey in colour; 

 and that they are sufficiently like the wild rabbit in 

 other respects also for them to be marketable as such. 



Leeuwenhoek's statement that the hybrids produced 

 by crossing piebald with wild rabbits are invariably 

 "grey" in colour — without any white — seems open to 

 question. Recent experiments have not yet solved 

 the problems of the inheritance of pied patterns jS 

 rabbits. Prof. Punnett, who has been studying tc| 

 matter for some years, tells me that when wild rabbits 

 are crossed with modern Dutch, " the F, animals may 

 be, though rarely, completely self-coloured. General 

 they have a little white. The amount of this vari< 

 but never approaches the amount found in the Dutch* 



The statement that the progeny of long-eared tartW 

 doe-rabbits and wild males never possess such long 

 ears as their mothers, appears to have been confirmee 

 by Castle. " He crossed the long-eared lop rabb^ 

 with ordinary short-eared individuals. F, had ears 

 intermediate length " (Bateson, " Mendel's Princip||^ 

 of Heredity," 1909, p. 251). I do not know of a 

 confirmation or contradiction of Leeuwenhoek's fir 



NO. 2361, VOL. 94] 



