;88 



NATURE 



[August 23, 1888 



by your distinguished correspondent was familiar to Mr. Darwin, 

 and that it was dealt with by him in the sixth chapter of the 

 "Origin," in what seemed to me to be the only way which was 

 then, or is now, possible. We should learn to understand it, 

 he said, by observing "by what graduated steps" [electrical 

 organs] "have been developed in each separate group of fishes." 

 By this I understand him to have meant that what we require 

 to know is, under what conditions the development of electrical 

 organs has actually taken place. 



On morphological grounds, we know that a striped muscular 

 fibre taken together with its nerve, and the electrical disk of the 

 organ of the skate taken together with its nerve, are homologous 

 structures — that is, that they are made up of corresponding parts, 

 and have corresponding places in the normal order of. develop- 

 ment ; so that they are in collateral, not in sequential, relation 

 to each other. In other words, both spring from the same 

 origin, not one from the other ; and the development of one is 

 quite as normal as of the other. An electrical organ is no more 

 an abnormal muscle, than a muscle a misdeveloped electrical 

 organ. 



In accordance with Mr. Darwin's teaching, external condi- 

 tions, whether antecedent or collateral, influence development 

 only in accordance with morphological laws — that is, with the 

 normal order of development. In the present instance we have 

 some knowledge of the order, but the conditions are unknown ; 

 and what we have to do is to ascertain what conditions of exist- 

 ence have given predominance to one order rather than to the 

 other, so as, in certain cases, to determine the development of 

 apparatus for producing electrical discharges in place of apparatus 

 for doing mechanical work. • 



This is the problem, and it will take a long lime to in- 

 vestigate it. We know a great deal more now than Mr. 

 Darwin did twenty- five years ago about the structure, develop- 

 ment, and mode of working of the electrical organ, but scarcely 

 more than he did about the "why" of its existence in such 

 animals as the skate. Nor shall we be able to give any better 

 account of it until time and opportunity have been afforded for 

 the examination and comparison of a much larger number of 

 instances than are at present accessible to us. 



I need only add a word as to his Grace's suggestion that the 

 electrical organ of the skate may be regarded as a " prophetic 

 germ." I would observe that, although in some species of skate 

 the organ is imperfect, it shows no sign of incompleteness in 

 others, and therefore cannot be properly designated a germ. As 

 to the organ being prophetic, I am not sure that I understand 

 what the word means. If the prophecy is such as might en- 

 courage the present race of skates to hope to be provided at 

 some future period with more efficient apparatus, I am afraid 

 that any such expectation on their part would be illusory. 



Oxford, August 15. J. Burdon- Sanderson. 



On the part of, I believe, a very large class of unprofessional 

 students of science and theology, I should like to express the 

 profound dissatisfaction, not unmingled with irritation, with 

 which we have read the Duke of Argyll's recent contributions 

 to the subject of evolution. The complete collapse of the 

 grave charges made against the advocates of evolution in the 

 article entitled "A Great Lesson" in the September (1887) 

 number of the Nineteenth Century, is too well known to need 

 comment. 



The letter on " Functionless Organs" affords another in- 

 stance of the illogical and dogmatic style with which we are 

 too familiar. Passing over any notice of the absolute incon- 

 ceivability of any cause for the development of " prophetic 

 structures," the Duke of Argyll once more repeats the ex- 

 ploded notion that " the element of fortuity is inseparable 

 from the idea of natural selection," whereas, as has been 

 proved over and over again, the ideas of fortuity and of evolu- 

 tion, of which process natural selection is so integral a part, 

 are absolutely incompatible. But perhaps the climax is reached 

 in the following quotation : "Hitherto I have never yet met 

 with a case in which an expert interprets functionless organs 

 as structures on the way to use." Having at last found a 

 solitary case which, it is thought, by one expert, may be in- 

 terpreted against the Darwinian conception of evolution, he 

 immediately jumps to the conclusion that " everywhere, in 

 reasoning and observation, it is breaking down." 



Apropos of Mr. J. G. Hurst's pertinent queries on p. 364 of 

 your last issue, it may be well to recall the Duke of Argyll's 



dictum given in the "Reign of Law," i.e. that in man's struc- 

 ture " there is no aborted member. Every part is put to its 

 highest use." Samuel F. Wilson. 



Warsop, August 18. 



Lamarckism versus Darwinism. 



It is to be regretted that Dr. Romanes has not written any- 

 thing which can be considered as a reply to my letter. Although 

 Prof. Weismann's essays, to which I referred, are certainly "two 

 of the most notorious essays in the recent literature of Dar- 

 winism," it is nevertheless equally certain that a large and 

 important part of their contents is devoted to the consideration 

 of the causes of variation. This being the case, I may safely 

 leave the evidence in support of the statement in my first letter to 

 anyone who will take the trouble to read p. 841 of the June number 

 of the Contemporary Reviezo. As it is probable that many people 

 have already read the article in question, and that others may 

 be induced to do so as a result of this correspondence, I think 

 that on this account it may be worth while for Dr. Romanes to 

 notice the criticism, and if possible to show that his remark 

 about Prof. Weismann is intended to bear some other than its 

 obvious meaning. 



I need hardly make any further reference to the second and 

 third paragraphs of Dr. Romanes's letter, for I have already 

 explained my position in my first letter. I need only reassert 

 that I was in no way influenced by Dr. Romanes's remarks or 

 opinions about myself; nor am I concerned to allude to the 

 personal references contained in his letter, except to express 

 regret if anything in the form as apart from the substance of my 

 first letter should have caused the annoyance which Dr. Romanes 

 takes no pains to conceal. 



In conclusion, it may be worth while to draw attention to the 

 curious coincidence which brings into the same number of 

 Nature a letter from Prof. E. Ray Lankester, containing an 

 expression of opinion diametrically opposed to that of Dr. 

 Romanes upon the interesting question of Lamarck versus 

 Darwin. Edward B. Poulton. 



Oxford, August 17. 



With reference to the recent revival of what may be con- 

 sidered as "pure" Lamarckism, it appears to me of importance 

 that those who have followed the course of biological work and 

 thought in this direction should at the present juncture declare 

 their views with respect to the interpretation of such results as 

 those obtained by Mr. Poulton, and referred to by Dr. Romanes 

 in his letter of August 9 (p. 364). I am glad of the present 

 opportunity of discussing this matter, because Mr. Poulton's work 

 is to a large extent an expansion and experimental confirmation 

 of views to which I gave expression in a paper published in 

 1873 (Proc. Zool. Soc, p. 159). I have no desire to enter into 

 the personal question as to whether Dr. Romanes has or has 

 not made himself acquainted with Weismann's essays, but I must 

 express my disappointment that he has not given us a more 

 explicit statement concerning the precise manner in which he 

 interprets the experiments in the Lamarckian sense. For my 

 own part I may add that I have had opportunities of witnessing 

 Mr. Poulton's experiments at intervals during their progress, and 

 of discussing their bearings with him, and I must confess that I 

 am at present completely at a loss to see how they can by any 

 means be interpreted in the manner Dr. Romanes suggests. 



The conclusions at which I arrived in the paper referred to 

 may be very briefly summarized. We find in many species of 

 insects, &c, a variability in colour which is distinctly of an 

 adaptive character, enabling the insect to become adapted to 

 a variable environment, and thus being obviously advantageous 

 to the possessors of such a faculty. From this it seemed but a 

 natural conclusion that such a power of adaptability should have 

 been conferred by the usual operation of the law of the survival 

 of the fittest. This conclusion I ventured to draw in 1873, after 

 carefully considering all the cases which I could collect. But in 

 thus grouping what I called at the time " variable protective 

 colouring" among the biological phenomena capable of being 

 regarded as the result of the action of natural selection, I was 

 careful to point out that the precise mechanism of the process by 

 which this adaptability was brought about remained to be 

 investigated for each case. This is the work which has been so 

 admirably carried out by Mr. Poulton for certain Lepidopterous 

 larvae, pupaj, and cocoons, and the results which he has obtained 

 go far to show that this adaptability in colour is possessed by a 



