Decembek 19, 1913] 



SCIENCE 



875 



I suggested some experiments something lilse 

 yours, and many otliers. I do not quite agree 

 with you that if acquired characters are inherited, 

 they might only be so very rarely. If inherited 

 (to be of any vise in the theory of evolution, and 

 that is the whole question) they ought to be in- 

 herited as frequently as other characters are in- 

 herited, that is, I presume, in about half the off- 

 spring. If only one in 100 exhibited the character 

 how could you possibly say it was not a normal 

 variation in that individual? Only by the very 

 frequent inheritance could you prove that there 

 was any inheritance at all! I think you will see 

 this. But it is too elaborate a question to discuss 

 in letters. 



On February 18, however, lie discussed the 

 matter at greater length: 



As you are a student of variation I thought you 

 would see my point without explanation. Now I 

 will explain. The following three points I con- 

 sider to be proved by overwhelming evidence, a 

 summary of which is given in ' ' Darwinism, ' ' 

 Chap. III. 



1. All increasing or dominant species (and it is 

 from these that new species arise) vary consider- 

 ably, in all their parts, organs and faculties, in 

 every generation. 



2. The amount of this variation is so large that 

 when only 20 to 50 adults are compared it reaches 

 from 10 to 20 per cent, of the mean value of such 

 characters as can be accurately measured. 



3. The proportion of individuals which vary con- 

 siderably is large, reaching to one fourth, or one 

 third of the whole number compared. In other 

 words, the curve of variation is low. . . . 



Hence it follows that whatever character is in- 

 creased or diminished in individuals by the effect 

 of the environment, a similar increase or diminu- 

 tion will occur by genetic variation, in each genera- 

 tion, and in certainly 5 or 10 per cent, of the in- 

 dividuals dealt with. Hence your supposition that 

 in the check lots no such modification would occur 

 as in those exposed to special conditions is almost 

 an impossible one; and an effect produced on one 

 or even on five or 10 per cent, by special conditions 

 would be imperceptible, because similar effects 

 would occur through normal variation and often 

 to a much greater amount. Hence I said, that to 

 be clear and decisive the effect produced by the 

 conditions should be inherited by a large propor- 

 tion of the offspring. You may say that the effects 

 of conditions would be additional to the normal ef- 

 fects of variation. True. And if largely inherited 



they would soon show it, but if as you first sup- 

 posed only one per cent., that would be entirely 

 swamped by the irregularities of normal variation 

 and inheritance. Tou must remember too that ex- 

 periments on a very large scale, and with check ex- 

 periments on an equally large scale, and all carried 

 on for many years, would require a very large es- 

 tablishment and ample funds not likely to be ob- 

 tained. Again, the whole raison d'etre of this en- 

 quiry is to decide whether inheritance of ac- 

 quired characters is of any importance in the 

 origin of species. To be of importance it must 

 rank in generality with variation, otherwise 

 it is entirely superfluous, even if it exists, and 

 variation could do perfectly well without it. 

 Yet again, either there is a fundamental cause 

 of such inheritance or there is not. If there 

 is, — if such inheritance is a law of nature, why 

 should it not rank with the inheritance of genetic 

 variations? — which are, I presume, to the extent 

 of about one half? If it was only one per cent., it 

 might be a fluke! It would require innumerable 

 experiments to prove it was anything else. 



I have given this discussion partly to show 

 that even in those days there was much talk of 

 experimental work, and that the necessity for 

 such work was fully appreciated. Dr. Romanes 

 prepared a statement, which was widely cir- 

 culated, urging that an experimental station 

 should be established at Oxford or Cambridge,* 

 but the funds were not forthcoming. We 

 thought at one time that Oxford would rise to 

 the occasion, but she failed to do so, and it was 

 long after that Cambridge established a chair 

 of genetics. 



During the winter I unsuccessfully com- 

 peted for a position in the Marine Biological 

 Station at Plymouth, and Dr. Wallace kindly 

 interested himself on my behalf. When, in 

 April, I was appointed curator of the nauseum 

 of the Institute of Jamaica, I had reason to 

 believe that Dr. Wallace had a good deal to do 

 with the matter, since he evidently knew all 

 about it before I told him. He wrote me a 

 charming letter of congratulation: 



How you will revel in the land Molluscs, and 

 how you will punish the poor slugs who have 

 hitherto been unregarded by collectors! . . . 



* ' ' Life and Letters of George John Eomanes, ' ' 

 second ed. (1896), p. 269. 



