June 17, 1922] 



NATURE 



777 



One would almost suppose that Mr. Bateson was 

 a bio-chemist. But how much chemistry is there 

 111 the analysis of Mendelian factors, or the identi- 

 lication of spots in chromosomes which represent 

 particular genes ? The suggestions of the nature of 

 the " chemical process " have come from the physio- 

 logists and from those who, without ignoring the 

 methods and discoveries of genetics, have not ceased 

 to discuss evolution and adaptation. It is true 

 iiat some geneticists have discussed the question 

 liether factors for colour might be chemical com- 

 umds reacting on each other, but they have not 

 < plained how chemical compounds such as enzymes 

 ul chromogens could be contained in separate 

 .romosomes and segregate from each other in the 

 luction divisions of gametes. I do not remember 

 • iiv case in which " modification by descent," that is 

 the loss or gain of a unit character, has been shown by 

 <j;eneticists to be due to any chemical process. The 

 latest results of the American investigators concern- 

 ing the localisation of genes in the chromosomes, 

 oncerning which Mr. Bateson states that all his 

 epticism has been removed, are purely morpho- 



W\ the progress that has been made in our know- 

 ledge of unit characters and of specific characters has 

 tended to exhibit more and more clearly the difference 

 between such characters and adaptational features. 

 It is seldom that an adaptation is confined to a single 

 species, and it is impossible to perceive any connexion 

 between mutations or unit characters and the relation 

 of adaptations to function and external conditions. 

 One great event in the evolution of both animals and 

 plants was the adaptation of the descendants of 

 aquatic forms to terrestrial and atmospheric condi- 

 tions. In the case of animals, we have, in the meta- 

 morphosis of Amphibia and the embryonic develop- 

 ment of higher vertebrates the recapitulation of this 

 transition from aquatic organs of respiration to 

 atmospheric organs, not by conversion but by 

 substitution. It is certain from this evidence that 

 I the change was perfectly gradual and continuous, and 

 parallel to the gradual change of conditions and mode 

 of life. Recapitulation in this case, however ancient 

 a subject it may be, is an obvious fact, and nothing 

 that the geneticists have discovered throws any light 

 on it, or diminishes its importance. It is no use 

 dismissing it as early Victorian. The question is, 

 have the recent, much vaunted discoveries explained 

 it, or have they anything to do with it ? Variations 

 in wings, eye colour, etc., of flies bred in milk-bottles 

 are important in their own sphere, but they throw no 

 light on the annual growth, denudation, death, and 

 recrescence of the antlers of a stag, or on the remark- 

 able relation between these processes and the hor- 

 mones from the gonads. The origin of species is a 

 very important problem, but it is not the whole, or 

 the most important part, of evolution. The origin of 

 adaptations is not the same problem as the origin of 

 species, and the methods of modern genetics have 

 very little bearing upon it. Mr. Bateson's address 

 suggests that he has not yet realised the difference 

 between the two problems, or paid serious attention 

 to modern physiological knowledge bearing on 

 functional adaptation." The phenomena of recapitu- 

 lation, so closely associated with adaptation, imply 

 wherever they occur a continuity in the evolu- 

 tionary change of which the adaptation was the 

 result, and these phenomena are quite incompatible 

 with the discontinuity which is characteristic of non- 

 adaptive variations, and which is the cardinal prin- 

 ciple of Mendelians and mutationists. 



J. T. Cunningham. 

 35 Wavendon Avenue, Chiswick, W.4. 



NO. 2746, VOL. 109] 



Evolutionary Faith and Modern Doubts. 



No one can have read without interest Dr. Bateson's 

 admirable address on evolution published in Nature 

 of April 29. While Dr. Bateson's reputation is justly 

 high and his views necessarily command respect, it 

 must be admitted that some of his arguments are 

 very difficult to follow. When, for example, he says 

 that " the conclusion that species are a product of a 

 summation of variations, ignored the chief attribute 

 of species, that the product of their crosses is fre- 

 quently sterile in greater or less degree," I am 

 frankly puzzled. The proposition is certainly not 

 self-evident. If a sword and its scabbard are bent 

 in different directions, it will happen sooner or later 

 that the sword cannot be inserted, and the result will 

 be the same whether the bending be effected by a 

 single blow, or whether it be, in Dr. Bateson's words, 

 " a product of a summation of variations." Is this 

 illustration inapt ? The sword and its scabbard are 

 the homologous chromosomes. These presumably 

 have to co-operate to produce the somatic cell of the 

 hybrid, and their co-operation might be expected to 

 require a certain resemblance, but for the production 

 of sexual cells they must do more, they must con- 

 jugate ; and for conjugation it is surely reasonable 

 to suppose that a much more intimate resemblance 

 woiild be needed. 



We might, therefore, expect, on purely theoretical 

 grounds, that as species and genera gradually diverged, 

 it would be increasingly difficult to breed a hylSrid 

 between them ; but that, even while a hybrid could 

 still be produced, a fertile hybrid would be difficult 

 or impossible, since the cells of the germ-track would 

 fail to surmount the meiotic reduction stage, w^hen 

 the homologous chromosomes conjugate. This is ex- 

 actly what happens : the cells go to pieces in the 

 meiotic phase. 



It would even seem that the argument is exactly 

 contrary to Dr. Bateson's statement of it : it seems 

 easier to imagine sterility arising from a gradual 

 modification, spread over a length of time, and in- 

 volving many chromosomes, than from the half- 

 monstrous variations chiefly studied by Dr. Bateson 

 and his school, variations which appear to affect only 

 a few chromomeres, and those by loss alone. 



Now I certainly cannot pretend to much or special 

 knowledge, either in genetics or cytology. But I 

 would ask Dr. Bateson in all humility whether there 

 is any difficulty involved in this simple solution of 

 his problem. Very likely there is, but he does not 

 indicate it. C. R. Crowther. 



2 Mutley Park Villas, Plymouth. 



Transcription of Russian Names. 



In Nature of May 20, p. 648, is published a 

 letter from Maj.-Gen. Lord Gleichen, who raises 

 objections to Prof. Brauner's suggestion (Nature, 

 April 29) that we should adopt the Czech tran- 

 scriptions for the names of Russian men of science. 



The argument that there are typographical diffi- 

 culties is surely a very small one, since Nature and 

 other journals {e.g. that of the Chemical Society) 

 already employ letters with diacritical marks in 

 writing the names of Czech and other authors. 

 Whilst diacritical marks are undesirable for place 

 names on maps, the same need not apply to the 

 names of persons. 



The main points raised by Prof. Brauner in support 

 of his suggestion, remain unchallenged, and in 

 addition to these it may be mentioned that the 

 Czech language is phonetic and Russian names 

 can thus be accurately pronounced according to it. 



2C 2 



