5. THE CONTEMPORARY REACTION TO MENDEL'S WORK. The peculiarities of Mendel's work, to which attention has been called in the previous sections, seem to contribute nothing towards explaining why his paper was so generally overlooked. The journal in which it was published was not a very obscure one, and seems to have been widely distributed. In London, according to Bateson, it was received by the Royal Society and by the Linnean Society. The paper itself is not obscure or difficult to understand ; on the contrary, the new ideas are explained most simply, and amply illustrated by the experimental results. In view of the parallel failure of the biological world to appreciate and follow up Darwin's experiments, it is difficult to suppose that, had Mendel's paper been more widely read, there would have been many mentally prepared to appreciate its significance. Some there certainly were ; and, had the new facts and methods come to the knowledge of Francis Galton, the experimental an*lysis of heredity might well have been established twenty-five years earlier than it was in fact; but minds equally receptive were certainly rare.
Among German biologists the one with whom Mendel is known to have corresponded is von Nägeli. From his writings it is apparent either that Mendel's researches made no impression on his mind or that he was anxious to warn students against paying attention to them. In a paper published December 15, 1865, only ten months after the delivery of Mendel's paper on peas, and before its appearance in print, he seems to reprove observers who venture to think for themselves and to plan their own experiments instead of using the results of Gartner and Kölreuter (p. 190) : "The knowledge of hybridization would in recent times have made more progress, if many observers, instead of beginning anew, had made use of the results of the two first-named German investigators, who applied the labour of their lives to the solution of this problem." In the beginning of his paper Mendel had, with modest confidence, contrasted his method of procedure with that of these two distinguished predecessors. In his final discussion, also, he reinterprets the results of Gartner in terms of the factorial system, show ing that Gartner's observations agreed with Mendel's theory, while dissenting from Gartner's opinion that they were opposed to the theory of evolution.
In spite of his correspondence von Nageli does not refer to Mendel's recent paper, and the following pa**age seems designed positively to ignore it (p. 231) : "Variability of the hybrids, that is to say, the diversity of forms which belong to the same generation, and their behaviour on propagation once or many times by self fertilization, form two points in the study of hybridization which are still least ascertained, and which appear to be the least subject to strict rules." Mendel had claimed to have established precisely such strict rules. Another pa**age in the same paper seems designed directly to contradict Mendel's claims as to the dominance and independence of genetic factors (p. 222): "The characters of the parental forms are, as a rule, so transmittedthat, in each individual hybrid both influences make themselves felt. It is not that one character is transmitted, as it were, unchanged from the one parent, a second unchanged from the other ; but there occursan interpenetration of the paternal and the maternal character, and a union between their characters." It is difficult to suppose that these remarks were not intended to discourage Mendel personally, without drawing attention to his researches.
No such dishonourable intention can be ascribed to W. O. Focke, who, in his Pflanzenmischlinge, makes no less tha n fifteen references to Mendel. As in the case of other voluminous compilers, most of these references, though doubtless relevant to the different topics Focke had in mind, ignore the point of Mendel's work. The nearest Focke comes to giving any idea of what Mendel had done is found in the following sentence. This may stand as a good example of the limitations of even the best intentioned compilers of comprehensive treatises (p. 110) : "Mendel's numerous crossings gave results which were quite similar to those of Knight, but Mendel believed that he found constant numerical relationships between the types of the crosses." The fatigued tone of the opening remark would scarcely arouse the curiosity of any reader, and in all he has to say Focke's vagueness and caution have eliminated every point of scientific interest. Could any reader guess that the "constant numerical relationships" were the universal and concrete ratios of 1 : 1 and 3:1, or even that Focke was speaking of the frequency ratios of a limited number of recognizable genotypes?
It is not an accident that Focke was vague. In this case, as perhaps in others, he had not troubled to understand the work he was summarizing. Mendel's discovery of dominance and the great use he had made of seed characters had escaped him altogether. His comment continues : "In general, the seeds produced through a hybrid pollination preservealso, with peas, exactly the colour which belongs to the mother plant, even when from these seeds themselves plants proceed, which entirely resemble the father plant, and which then also bring forth the seeds of the latter." H. F. Roberts makes an instructive comment on Focke's book : ''A careful study of Focke's report brings into interesting relief the reason for his having failed to appraise the Mendel paper at its present value. In the first place, Focke was especially interested in theworks of those who produced more extended contributions. The work of Kölreuter, Gärtner, Wichura and Wiegmann, whose works weremuch more voluminous in the field which they occupied, receive appropriate consideration, as do also Naudin's and Godron's prize contributions; but Mendel's paper evidently appeared to Focke simply in the guise of one of the numerous, apparently similar, contributions to the knowledge of the results of crossing within some single group . . . It was supposedly not at all conceivable that the laws of hybrid breeding could be compa**ed within a series of experiments upon a single plant." Roberts ends his comment on a note of appreciation : "The details of his (Focke's) data are laborious, exact, well-cla**ified and scientifically arranged, comprising 79 families of dicotyledons, 13 families of monocotyledons, 2 families of gymnos**ms, 2 of pteridophytes, one of the musci and one of the algae." It is very well to be reminded that the high qualities catalogued in the sentence last quoted are yet compatible with the learned author having overlooked, in his chosen field, experimental researches conclusive in their results, faultlessly lucid in presentation, and vital to the understanding not of one problem of current interest, but of many.
The peculiar incident in the history of biological thought, which it has been the purpose of this study to elucidate, is not without at least one moral—namely, that there is no substitute for a careful, or even meticulous, examination of all original papers purporting to establish new facts. Mendel's contemporaries may be blamed for failing to recognize his discovery, perhaps through resting too great a confidence on comprehensive compilations. It is equally clear, however, that since 1900, in spite of the immense publicity it has received, his work has not often been examined with sufficient care to prevent its many extraordinary features being overlooked, and the opinions of its author being misrepresented. Each generation, perhaps, found in Mendel's paper only what it expected to find ; in the first period a repetition of the hybridization results commonly reported, in the second a discovery in inheritance supposedly difficult to reconcile with continuous evolution. Each generation, therefore, ignored what did not confirm its own expectations. Only a succession of publications, the progressive building up of a corpus of scientific work, and the continuous iteration of all new opinions seem sufficient to bring a new discovery into general recognition.