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NATURE 



[Jan. 30, 1890 



easily understandable manner. There are some very few i 

 points in the author'sexplanationsof phenomenaas regards I 

 which we cannot quite agree with him. For instance, when 

 he is considering the action of light on silver chloride he 

 states that an oxychloride is formed (on the authority of 

 Dr. Hodgkinson). That this is not always the case is 

 shown by the fact that silver chloride is darkened when 

 exposed in the presence of bodies which contain no 

 oxygen, as, for instance, when the exposure is given in 

 benzene. The author has adopted the plan of calling his 

 chapters lectures, and in this instance we shall find no 

 fault with what often is an artifice to cover slipshod 

 writing, since the subject-matter is good, the language 

 clear, and descriptive experiments are appended after each 

 note in the narrative. We feel assured that if a student 

 be fairly grounded in elementary chemistry and carries 

 out these experiments, he will have a far better knowledge 

 of the theory of photography than nine out of ten students 

 possessed before this work was written. The author 

 rightly points out that much in the theory of photography 

 still requires elucidation, and with this we quite agree ; but 

 by putting into a connected shape those portions of the 

 theory which may not require reconsideration, he has 

 done much towards facilitating the solution of the remain- 

 ing problems which are still sicb judice. 



The Popular Works of Johatm Gottlieb Fichte. Trans- 

 lated from the German by William Smith, LL.D. 

 With a Memoir of the Author. Fourth Edition. In 

 Two Vols. (London : Triibner and Co., 1889.) 



These volumes form part of the well-known " English 

 and Foreign Philosophical Library." The translations 

 included in them were first published in 1845-49, when 

 German philosophy had only begun to attract attention 

 in England. Fichte holds so clearly marked a place in 

 the development of modern thought that it is still worth 

 the while of students to make themselves famihar with 

 his governing ideas ; and there can be no disadvantage in 

 their beginning with his popular rather than with his 

 more systematic works. So far as the form of Fichte's 

 teaching is concerned, it cannot of course be said to meet 

 the needs of the present day. To many minds there is ! 

 something even irritating in his use of large, abstract 

 expressions, which are incapable of precise definition, 

 and in the dogmatic tone in which he proclaims his con- 

 victions, as if he had somehow had special access to the 

 sources of absolute truth. But his effort to solve the 

 questions which lie behind the problems of physical 

 science has at least the interest that belongs to perfect 

 sincerity ; and his methods and conclusions, whether 

 they commend themselves to our judgment or not, are 

 often in a high degree suggestive. He was personally of 

 so manly and noble a character that his popular writings, 

 in which he expressed his sympathies and tendencies 

 freely, are perhaps more valuable from the ethical than 

 from the strictly intellectual point of view. Dr. Smith's 

 work as a translator is, we need scarcely say, excellent ; 

 and the like may be said of his work as a biographer. 

 His memoir of the philosopher is written in a thoroughly 

 appreciative spirit, and with adequate knowledge. 



Travels in France. By Arthur Young. With an In- 

 troduction, Biographical Sketch, and Notes, by M. 

 Betham- Edwards. (London : George Bell and Sons, 

 1889.) 



Everyone who has given even slight attention to the 

 pre-revolutionary period of French history knows, at 

 least by hearsay, something about Arthur Young's 

 " Travels in France." No other work of that time 

 throws so clear and steady a light on the social and 

 economic conditions which prevailed among the mass of 

 the French people immediately before their great national 

 convulsion. This is well understood by French historical 

 students, who have found in the record of Young's ob- 



servatiolis a tnine of information on the very subjects 

 about which they are most anxious to obtain trustworthy 

 contemporary statements. The present reprint deserves, 

 therefore, to be cordially welcomed. It has been care- 

 fully edited by Miss Betham-Edwards, who, in an in- 

 teresting introduction, prepares the way for the study of 

 the book by presenting " a contrasted picture of France 

 under the ancien regime and under the third Republic." 

 She also gives a valuable biographical sketch of Arthur 

 Young, the materials having been supplied by his grand- 

 son. 



LETTERS TO THE EDITOR. 



yrht Editor does not hold himself responsible for opinions ex- 

 pressed 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. '\ 



Acquired Characters and Congenital Variation. 



Mr. Dyer accuses me of invading the pages of Nature by 

 methods of discussion characteristic of the political debater. 

 Those methods, however, may be good as well as bad. In 

 addition to direct affirmative arguments in support of a particular 

 conclusion, they may trace the working and the power of pre- 

 conceptions which in science, as well as in other things, are an 

 abounding source of error. On the other hand, methods of 

 debate may be confused and declamatory, dealing in vague 

 phrases, and delighting in clap-trap illustrations. If I could not 

 handle a scientific question by some method less adapted to the 

 " shilling gallery " than the method of my censor in this case, 

 I should wish to be silent for evermore. In his letter I see 

 " Teleology " compared to "a wise damsel ". who is "tempor- 

 arily ruffled," but who nevertheless "gathers up her skirts 

 with dignity." I see Addison brought in, head and shoulders, 

 with "the vision of Mirza." I see Fortuity described as "in- 

 separable from life," with the somewhat obscure oratorical 

 addition that "it is at the bottom one of the most pathetic 

 things about it." I see mixed metaphors of all sorts and kinds, 

 "the church," and "orthodoxy," and "automatically self-re- 

 gulating machines," and "tenacity about outworks " — and many 

 other such words and phrases — all handled according to methods 

 which do not strike me as at all perfect examples of true scientific 

 reasoning. 



Nor am I able to follow Mr. Dyer's logic better than I can 

 admire his declamation. The object of my last letter, which he 

 attacks, was to lay down and defend the proposition that " there 

 is no necessary antagonism between congenital variation and 

 the transmission of acquired characters." Mr. Dyer admits this 

 proposition to be " perfectly reasonable," adding, in respect to 

 this supposed antagonism, "theoretically there is none." But 

 then he proceeds to say, " this does not make the transmission 

 of acquired characters less doubtful." In other words, the com- 

 plete and effectual removal of an adverse presumption is of no 

 value in an argument which rests altogether on difficulties and 

 doubts. This would be unreasonable enough considered merely 

 in the abstract. But it becomes still more unreasonable when 

 we recollect that the whole doctrine of evolution implies, of 

 necessity, the continual rise of new characters and the transmis- 

 sion of them. These new characters are "acquired" in one 

 sense, and they may be congenital in another. They not only 

 may be, but probably they must be, acquired from latent con- 

 genital tendencies, and they may be fixed and transmitted only 

 by those tendencies ceasing to be latent. On this view of the 

 matter, the present controversy between the two conceptions 

 becomes a mere logomachy. The diffisrent breeds of dog do 

 undoubtedly transmit characters which have been "acquired." 

 But it is always possible to assert, and always impossible to deny, 

 that these characters arose out of congenital tendencies latent in 

 the species. Mr. Dyer's assertion that this method of reconcil- 

 ing the two ideas ' ' does not make the transmission of acquired 

 characters less doubtful," is an assertion, therefore, which is 

 obviously wrong. The reconciliation attacks the difficulty about 

 the " inheritance of acquired characters " at its very heart and 

 centre. It shows it to lie — as a thousand other difficulties have 

 lain before — in an ambiguous word. ' ' Acquired " ? Yes ; but from 

 what? From "use"? Yes, but whence came the possibility 



