78 



NATURE 



[May 



■O' 



189 = 



LETTERS TO THE EDITOR. 



[ The Editor does not hold himself responsible for opinions ex- 

 pressed by his correspondents. A'either can he iinderlake 

 to return, or to correspond with the UTiters of, rejected 

 manuscripts intended for this or any other part of NATURE. 

 Ko notice is taken of anonymous communications.'^ 



The Origin of the Cultivated Cineraria. 



It appears to me that Mr. Bateson very ini|)erfeclly .tppreciates 

 the nature of the problem of which he has hazarded what I 

 venture to think an ill-considered solution. 



In my last letter I pointed out briefly the grave objective 

 ilifticulties which he had to face in substantiating his case. As 

 Mr. Bateson is, by reputation, a serious naturalist, I think it 

 was his duty to take up the challenge which I virtually threw 

 down to him, and deal with the points which I brought under his 

 consideration. This he has not chosen to do, but falls back 

 again upon his " historical eWdence"' and his dialectic. 



Now I must confess that I am myself as nnich bored as 

 I suppose most people must be with the "modern Cineraria." 

 .\nd I grudge the time demanded for the discussion of a point 

 which I brought forward as a merely incidental illustration. 

 It may, however, be useful in saying all that I intend to say in 

 reply to Mr. Bateson, to make a few general remarks on the 

 whole subject. 



It is ap|xirently the fashion nowadays for the younger biologists 

 to undertake the reconstruction of the Darwinian theor)'. The 

 field is undoubtedly open, and posterity may safely be trusted to 

 appreciate the value of their labours. But I cannot but observe 

 that as .between them and the author of the theory, there is this 

 difference. Mr. Darwin, as he has told us, spent the best part 

 of his life in studying patiently and sifting critically a vast nia.ss 

 of observation and fact. Ultimately he permitted himself 

 to draw certain conclusions. The result is thai if you take 

 any statement which Mr. Darwin has |)ut forward, you 

 may feel assured that behind it is a formidable botly of 

 carefully considered evidence not likely to be uiwet. 

 With the mo<lem writers on evolution, the ]X)sition is 

 exactly the opposite. They laimch their theories gaily on the 

 world, and on demanding their substratum of facts, one is lold 

 that that is a matter fi>r future collection. I myself am old- 

 fashioned enough to think that, of the two methods, that of Mr. 

 Darwin is the sounder, the more .scientific, and in the long run 

 the ni<ire convincing. 



I have pointed out again and again the vast wealth of material 

 for lhc..Mientific study of variation which is presented every day 

 to the eyes of any one engaged in horlicullural practice. The 

 difficulty is that few |iersons jxissess either the scientific ca|iacity, 

 the fKilience, or the leisure for its profitable utilis;ition. We 

 want, in fact, for the pur|x)se a .second Darwin, or at least a 

 Herbert. 



In his "Variation of Animals and Plants under Domestica- 

 tion," .Mr. Darwin made a use which was remarkably cfTeclive 

 of the ol»ervations made by " pr.ictical men" in horticultural 

 lileralure. They served his |)ur)iose in establishing, as had never 

 liccn done Ijcfijre, the amount and character of the variation 

 which was pos,sible under artificial conditions, and therefore, by 

 analogy, under natur.il. But this class of evidence ap|)ears to 

 me un.sati.sfactory for the investigation of the further jiroblem 

 which is at the mf)ment of supreme interest, the nature and laws 

 of variation itself. I think that Mr. Darwin s<|ueezed out of it all 

 that it would profitably yield. And for this reason : the evidence 

 is not scientific — that is to say, it w.is never drawn up by persons 

 having in view the re<)iiirenienls of scientific ex.nctilude. Tlmse 

 whf» gave it have lieen prevsed into court in a cause in «hich 

 they never contemplated eng.aging. This has the merit iif en- 

 suring that their evidence is unbi.-i.vsed, but it does not allow 

 of it.s tx-ing pu.shed further ihiui what it is ca|»ble of jiroving. 



The defects of horticultural evidence may Ik: illustrated in a 

 variety of ways. One or I wo will suffice. In the first place, is 

 the wc^akness of its nomencLature. llr>rticullurists are mil, for 

 the mrwl |)art, skilled liolanists. When they give a plant 

 name, it is im|M)ssilile to lie .sure that it is what a technical 

 botanist would accept. It is as if one were reailing the writings 

 of a chcniLsl, and when he mentioned |)ota.ssium, the doubt 

 occurred .-u lo whether it w.ts not lithium which w.is intended. 

 I do not mean to imply any censure on the horticulturists ; 

 they use names current at the m.iment which are giH.d enough 

 for practical imrposcs, though they will not stand a critical lest. 



NO 1334, VOL. 52] 



But in after years no technical botanist would dream of accepting 

 them as unimpeachable. 



.■Vgain, it has often been found that where remarkable hybrids 

 have been recorded, it has been ascertained later that no cross 

 has in point of fact been effected at all. Vet the original 

 announcement will be quoted, and often has been as an undoubted 

 evidence of the fact. 



I arrive, then, at the conviction that if any profitable use is to 

 be made of horticultural experience in the study of variation, the 

 .so-called historical evidence will have lo be discarded. Kvery 

 step of the investigation must be made under the actual eye of 

 a competent observer, and nothing taken at second-hand. 



I will now return to the Cineraria. The feral form had been 

 long lost to cultivation, but some years ago it wets reintroduced to 

 Kew from the Canaries. Mr. Kolfe, a member of my .scientific 

 staff, illustrated it in the Gardeners' Chronicle in iSSS, and 

 ])ointed out the striking changes which it had exhibited under 

 cultivation. These have subsequently interested me because I 

 have been endeavouring to collect facts as to the rate of 

 variation. 



Now Mr. Bateson, solely on what he calls historical evidence, 

 still a.sserls, and in the face of the difficulties which I have pointed 

 out that such a theory jirescnls, that the modern Cineraria is of 

 hybrid origin. \'ery \\ ell : let us assume that as a (novisional 

 hypothesis. How is it to be tested ? It is e.i.sy to see from an 

 analogous case. The horse and the zebra have been crossed ; are we 

 justified in asserting that the last w inner of the Derby is of zebra 

 <lescent ? The criteria are two, and I think two only: (l) an 

 uncontested pedigree ; (2) palpable marks of ]>aienlal characters. 



Now, with regard to(l). jiraclically in ]>lanls it cannot be 

 obtained. We can only fall back upon " historical evidence." 

 I have attempted to show alxne, in a general way, how little 

 scientific value can ordinarily be attributed to this. One cannot 

 be sure that the asserted ]x\renls were what they are staled to 

 be. But my object was not to un<lermine the weight of what 

 Mr. Bateson has brought forward. I accept it and reject it as 

 wholly irrelevant. .\s my friend I'rof. Kolleslon was fond ot 

 saying, it would be valueless evidence even lo com id a i>o.acher. 



The fad that certain shrubby Cinerarias with hoary leaves and 

 one with yellow Ikiwers were crossed (if they really were) early 

 in the century, proves nothing as to the existing Cineraria, any 

 more than the cross between the zebra and the horse does as to 

 the parentage of any existing hor.se. 



These shrubl)y Cinerarias were, as .Mr. Bateson states, pro- 

 jiagated by cuttings (they are not loo easy to strike) ; and like 

 many other inleresling ]ilants, they disappeared from all but 

 botanic gardens towards ihe middle of the present cciUuiy. 



.•\s I am quite unable, then, lo attach any weight to the so- 

 called historical evidence, because I fail to see that it establishes 

 any filiation between the ]ibnts with which it deals, strikingly 

 ilifrerenl as they are, and the plant with which I am dealing, 

 there is nothing left but lo try (2), .and see what evidence of ils 

 |)arentage the |ilant itself alVords. 



Now, it is well known that organisms of hybrid origin pre- 

 serve, in some degree, their parental characters, aiui this has 

 even been shown lo be true of their histological elemenls. 

 Modern taxonomic botany has met with considerable success in 

 the analysis of plants of hybrid origin into their conslituents. 

 The Kloras have in consetjuence been cleared of a multitude ttf 

 dubious plants, the real nature of which can now he accounted 

 for. Anil the validity of the melhoil has been establislied by the 

 results of a corresponding synthesis. We had, then, no hesitation 

 at Kew in applying the lest lo the Cineraria. .Although it had often 

 been examined before, with the .-ussistance of some members of 

 my slafl' I made a fresh examination. I took copious specimens, 

 of Cineraria crueiita, and of an average cultivateil form, and 

 carefully compared them point by ]>oinI. Mxce]>t in the imilli- 

 plicitiijn of ihe llorets in the heads, especially of the ray-florets, 

 we could distinguish no tangible morphological ililVeience. In 

 fad, having accidentally mixed up leaves belonging to the two 

 imrcels, I found myself unable with any certainly to refer them 

 i«ick again. This is jirelly conclusive evidence of the actual 

 morphological iilenlily of the vegetative organs of the two plants. 



The next ihing was to c<impare the cultivated Cineraria with 

 its reputed shrubby "historical" ]»arents. These present 

 well inarke<l ami somewhat peculiar characteristics not re.adily 

 described in nontechnical language. But Ihe cull ivated Cine- 

 raria does not present the smallest trace iif any one of them. .\s 

 far, then, as the matter admits of investigation at all by any 

 known methods, I reganl Ihe cmclusiim which is generally 

 .iccepled here as a sound one. At .any rale, it rests on a careful! 



