January 4, 1906] 



NA TURE 



take four days each way. I am afraid, however, that it 

 might prove very difficult to secure any sample of this 

 stone for transportation to Europe. Alfred Tingle. 

 Chinanfu, Shantung, China, November 9, 1905. 



Aurorae of November 15 and December 12. 



Since my communication of December 9 (Nature, 

 December 28), 1 have learned that the aurora borealis 

 of Ni vember 15 was observed here by several persons 

 between 8.30 p.m. and 9.30 p.m., Halifax time. The 

 appearances were similar to those noted in England 

 (Nature, November 23, pp. 79-80), and the rosy-red 

 streamers seem to have attracted special attention. 



1 am also informed that an aurora was observed here 

 last night (December 12) at 9.30 p.m. with whitish 

 streamers, but lacking the display of colour observed 

 November 15. 



It is somewhat noteworthy that the interval November 15 

 to December 12 covers a period of twenty-seven davs — the 

 time required for one complete rotation of the sun. 



Alexander Graham Bell. 



Beinn Bhreagh, near Baddeck, Nova Scotia, 

 December 13, 1905. 



The Principles of Heredity. 



I have every reason to be satisfied with the kind and 

 indulgent review (December 7, p. 121) by " A. D. D." of 

 my book "The Principles of Heredity," but there is one 

 sentence of it on which I should like to comment, more 

 particularly as it contains nothing of blame or praise. 

 "A. D. D." writes, "this book ... is an embodiment 

 of the recognition by medical men that they depend 

 ultimately for a precise knowledge of nature on the pro- 

 fessional biologist — who may or may not, at the same 

 time, be a medical man." 



But really I do not think that. On the contrary, I 

 believe it is easily capable of demonstration that the in- 

 formation already in the hands of all medical men is incom- 

 parably superior, both in precision and volume, to anything 

 ever possessed, or likely to be possessed, by biologists. It 

 has not been utilised, that is all. The blame does not rest 

 wholly with the medical man. His strictly professional 

 curriculum is burdened by a monstrous but necessary load 

 of facts. His one chance of coming in contact with sub- 

 jects of general interest and of acquiring habits of sustained 

 and accurate thought lies in the purely scientific part of 

 his curriculum. Here his teachers are biologists who, in- 

 stead of inculcating wide principles of heredity and evolu- 

 tion, add to the load on his memory bv supplying irrelevant 

 scraps of information about jelly-fish, earthworms, cock- 

 chafers, and the like — irrelevant, for, in the form they are 

 presented, they do not link up with the studies and interests 

 ol his future career, and therefore are forgotten as soon 

 as may be. "A. D. D." complains that I do not 

 sufficiently appreciate classical teaching. It may console 

 him to know that my appreciation of a certain class of 

 scientific teaching is just as — well, hearty. 



The biologist has surpassed the medical man in the study 

 of great problems only because his attention has been 

 directed to the subject, and because, on the whole, his 

 habits of thought — not information — have been more 

 pre ise. Had the medical man received the training of the 

 biologist, or the biologist possessed the information common 

 10 medical men, the progress of science would have 

 been much mere rapid, and few or none of the great 

 biological controversies of the past would have arisen, or 

 at least have endured the interminable time thev did ; for 

 ih disputes as to whether natural selection is 

 the cause or the sole cause of evolution, as to whether 

 acquired characters are transmissible, as to whether varia- 

 tions are due to the direct action of the environment, as 

 to whether evolution proceeds on lines of " fluctuating " 

 variations or of discontinuous " mutations," as to the 

 function of sex, and so forth. 



Of necessity we — that is, all men — know the human 

 type better than we can possibly know any other. Pro- 

 vided we know what to look for, extreme familiarity 

 enables us to observe the smallest variations. Xo shepherd 

 knows his flock, no biologist knows animal or plant as 



NO. 1888. VOL. 73] 



the medical man knows his fellow man. The species has 

 diverged into a large number of natural varieties, dwelling 

 under immensely diverse conditions and differing vastly in 

 every peculiarity of body and mind. All these varieties, 

 apparently, are inter-fertile, and almost all of them, in 

 bulk or in isolated cases, have crossed with almost every 

 other variety. Hybrids are being reared every day, and 

 many races are compound hybrids — e.g. the Caucasian- 

 Negro-Indian inhabitants of parts of South America. 

 Above all, the species is being stringently selected and is 

 undergoing rapid evolution under the action of disease, an 

 agency which furnishes the most perfect series of experi- 

 ments in heredity and evolution imaginable. Every race 

 is resistant to every disease strictly in proportion to its 

 past experience of it. Some diseases are short and sharp, 

 others are of long duration. Some are local, others fill 

 the whole system with micro-organisms or bathe the germ- 

 cells with toxins. Many diseases are new- to many races ; 

 others they have afflicted for thousands of years. If ever 

 acquirements are transmitted, however " faintly and fit- 

 fully," it should be in the case of disease. If ever varia- 

 tions, no matter how small, are caused by the direct action 

 ol the environment, a race long afflicted should show the 

 trace. If Mendelian phenomena play an important part 

 in nature, we should note them in crossed varieties of men. 

 If evolution proceeds on lines, not of fluctuating variations, 

 but of stable mutations " which only selection can 

 eliminate," then races (e.g. British) which have become 

 highly resistant to this or that disease (e.g. consumption) 

 should not constantly produce individuals who are as 

 susceptible as members of a race which has undergone no 

 such evolution (e.g. Red Indian). 



Unless heredity in man differs from heredity in other 

 species, it is very evident that medical men have no need 

 to go to biologists for precise information, but that there 

 is every need that biologists should go to medical men. 

 A vast fund of minutely accurate data, much of which is 

 statistical, is available. To grope in the obscurity that 

 necessarily surrounds the past and the present of wild 

 species or amid the confusion of the unrecorded crosses 

 of domesticated varieties while this fund is untouched may 

 be magnificent, but it is not science. 



Southsea, December 11, 1905. G. Archdall Reid. 



Dr. Reid takes exception to a passage in my review of 

 his book; in it I state my belief that his book is the 

 embodiment of a certain opinion, but Dr. Reid writes to 

 say that he does not hold this view at all. It is not 

 necessary, nor would it be profitable if it were, to discuss 

 who is right in this matter — he or I — for obviously I am 

 guilty of misrepresenting Dr. Reid's opinion. 



But that the medical man is capable of acquiring a 

 precise knowledge of nature independently of the inform- 

 ation already gained and the methods employed by the 

 biologist does not seem to me to be by any means certain. 

 Dr. Reid thinks it is, and brings forward as evidence the 

 fact that doctors possess better data for the solution of 

 problems of evolution than ever have been, or can be, 

 possessed by the biologist. Now, even supposing this to 

 be true — which I do not for a moment — it does not seem to 

 me to prove Dr. Reid's point. Either he thinks that the 

 possession of data is tantamount to a precise knowledge of 

 nature, or he does not ; if he does, he proves his point by 

 introducing into his syllogism a premiss which I believe to 

 be untrue; if he does not — and I do not believe that he 

 does — he does not prove his point. 



But he this as it may, the point that interests me is 

 that the belief that there is no great step between the 

 collection of data and the derivation from them of a precise 

 knowledge of nature is a widespread and, I believe, a 

 profoundly erroneous one ; for it seems to me that the 

 possession of data is a small advance towards such a 

 precise know-ledge, and that that which hinders the acquisi- 

 tion of natural knowledge is not the slowness with which 

 facts are accumulated, but the paucity of investigators 

 capable of dealing with them properly ; and this dearth 

 is due to the infection of the majority of biologists by a 

 disease— a sort of sleeping sickness — which consists in a 

 disinclination to picture to the mind's eye the things re- 

 presented by the words they use. 



Let us proceed to examine Dr. Reid's main thesis — that 



