426 



NATURE 



[June 2, 192 1 



take me between finger and thumb and eat me like a 

 shrimp. 



At least one great biologist, Darwin, tried to 

 test his supposition with Newtonian candour and 

 thoroughness. So far as I am able to judge, dis- 

 belief in natural selection is now felt only by people 

 who decline to submit their opposing suppositions to 

 a similar course of rigorous testing. But, to judge 

 from literature, as a general rule, biologists seem to 

 think that, as in description, the facts (or similar 

 facts) on which an hypothesis is founded sufficiently 

 prove the truth of it. Hence, in the lack of crucial 

 testing, the chaos of opinions. Hence the rival 

 doctrines and schools. Hence the unending con- 

 troversies. Hence the absence of truth accepted 

 by everyone. Hence the particular value set by 

 this sect or that on evidence collected in this 

 way or that, and the neglect of all other evidence. 

 Hence, its inaccuracies undetected, the perpetuation 

 of a loose terminology. Hence, for example, the two 

 hundred explanations of sex. All these explanations 

 must have been guesses ; or, if one was fully tested 

 and established, biologists have not recognised it. 

 Biology is happy in the possession of vast and diver- 

 sified arrays of facts suitable for crucial testing. Bio- 

 logists are unhappy in that they do not use them. 

 Their scientific methods are four hundred years 

 behind those of physicists, and I suppose four 

 thousand years behind those of mathematicians. I 

 think all biologists must agree to this, if not as 

 regards themselves, yet as regards the prejudiced 

 adherents of rival sects. Crucial testing is the very 

 soul of interpretative science. It is that which guides 

 and controls the scientific imagination. But, as 

 religious enthusiasts, politicians, and some men of 

 science demonstrate, if you have not been trained to 

 use it and submit to it,' it is often nothing to you. 



May I, by way of example, give one instance of 

 what appears to me wasted opportunity? I choose a 

 subject which does not seem to have gathered sec- 

 tarian odium. It is not especially easy as biological 

 problems go. I imagine every other problem now in 

 dispute could be solved as simply if crucial testing 

 were employed and its results accepted. Judging 

 from embryos, some biologists have concluded 

 that the individual in his development recapitu- 

 lates the evolution of his race. On the same, 

 or similar, evidence other biologists have reached a 

 contrary conclusion. Both opinions are mere guesses, 

 and, used in this way, the facts afford no opportunities 

 for crucial testing. But consider them from another 

 aspect. Consider the evolution of a structure — for 

 example, an antler — in a line of individuals A, B, . . . 

 Y, Z. 



The first rudiments of the structure appear in A. 

 The structure increases by progressive variations in 

 B, C, . . . L, M. But B cannot produce his own 

 variation without recapitulating that of A, C cannot 

 achieve his development without recapitulating first 

 A and then B. M cannot develop without reproducing 

 in turn every ancestor up to A. To this point the 

 development must necessarily have been an accurate 

 recapitulation of the life-history of the race. But 

 now N varies retrogressively — that is to say, he omits 

 some part of the development, and therefore of the 

 evolution. If N reverts to K, L and M disappear 

 from future editions of the life-history, which thus 

 becomes inaccurate. O resumes the progression. _ P 

 interpolates a variation {e.g. the beginning of a tine) 

 at the stage reached by F, introducing another in- 

 accuracy. So the evolution continues until in Z the 

 development, recapitulating not only some of the 

 original history, but also many additions and sub- 

 tractions, presents onlv a vague, inaccurate, fore- 

 shortened outline of the evolution — most vague, as 

 NO. 2692, VOL. 107] 



a rule, in its earlier parts, which have been most often 

 repeated, and, therefore, subjected to most alteration. 



There is a history in all men's lives 

 Figuring the nature of the times deceased. 



This history is not told in words, but in graphic 

 signs, in mimicry ; and like a written history, copied 

 by a thousand hands and altered to suit the times, it 

 has become inaccurate. 



To put the thing in others words : if the son copies 

 with alterations the development of the parent, if 

 the parent copied the grandparent, and so on up to 

 the remotest ancestor — the unicellular represented by 

 the germ — how is it conceivable that development can 

 be other than a recapitulation, however inaccurate, 

 of evolution ? But inconceivability is not sure proof. 

 It may result from the incapacity of the thinker. 

 Turn, therefore, to crucial testing, for which facts 

 are now available. If it be true that development is 

 inaccurate and incomplete recapitulation, embryos 

 should present the appearances, however vague, of 

 ancient ancestral types. This is exactly what we find. 

 Consider a butterfly. It begins life in the egg, where, 

 quiescent and sheltered, it develops in an environ- 

 ment very unlike that in which the ancestral proto- 

 types struggled for existence. At this stage, there- 

 fore, recapitulation should be much altered, vague, 

 rapid, foreshortened, a mere scaffolding. The cater- 

 pillar must fight actively for existence in an environ- 

 ment which probably resembles closely that of its 

 prototypes. Probably, therefore, the animal itself 

 closely resembles its prototypes. It increases in bulk, 

 but otherwise changes little. Quiescent and shel- 

 tered, a chrysalis, on the other hand, alters rapidly and 

 enormously except in bulk. In the butterfly develop- 

 ment has ceased. In man, sheltered and quiet in the 

 uterus, there undergoing vast changes, but afterwards 

 altering little save in bulk, development pursues the 

 same lines. So also in every other type of multi- 

 cellular being. Consider how sheltered is the develop- 

 ment and how rapid the recapitulation in the seeds 

 of plants, and how small, relatively, are the subse- 

 quent alterations, except in bulk. 



If anyone can now think of development as other 

 than recapitulation, he is capable of an intellectual 

 feat beyond my powers. If I am right, I have fur- 

 nished evidence that it is possible to solve even the 

 more difficult biological problems by paying atten- 

 tion to the ordinary rules of scientific procedure. If 

 I am wrong, biologists should, like the physicists, be 

 able to eat me like a shrimp. 



Here is a significant thing. No man of science, 

 not a biologist, who knows the facts and has read 

 what I have written will ever again be able to 

 conceive of development as other than recapitula- 

 tion ; and often, when he thinks of a seed, an egg, 

 an embryo, or a chrysalis, he will wonder what aeons 

 are being traversed within these amazing time 

 machines — the " resting stages " of the biologists. 

 But no biologist will be interested or will alter his 

 antecedent opinions a hair's-breadth. He will merely 

 be shocked at the impudence of one who is neither 

 a botanist nor a zoologist. G. Archdall Reid. 



9 Victoria Road, Southsea. a^^ X 



The Great Sun-spot Group and Magnetic Disturbances, 

 May 8-21. 



On May 8 there appeared on the sun's eastern limb 

 an equatorial sun-spot in a region which has been 

 without disturbance for some considerable time. It 

 was an active spot which had Separated by May 12 

 into two large spots. The maximum area of the group 

 was 16-5, in units 1/5000 of the sun's visible disc, 

 and this was attained on May 14. The leader spot of 

 the group was a composite spot containing two umbrae. 



