March 13, 1890] 



NATURE 



437 



not authority the arbiter in cases of doubt, are the 

 conclusions which the author inculcates throughout. 



A century ago it was considered a fundamental principle 

 that venesection was essential in most, if not all, serious 

 illnesses ; and, to such an extent was this carried, that 

 200 ounces of blood were sometimes drawn off during 

 a week, and even half that amount in 24 hours. Next 

 came a reaction, and the theory that fever patients 

 required stimulation, rather than venesection, led to the 

 administration of enormous quantities of alcohol, espe- 

 cially at the hands of Dr. Todd, who at times administered 

 more than four gallons of brandy to young girls during an 

 illness. Finally, to Dr. Gairdner himself is due much 

 of the credit of the modern treatment ; for in 1864 he 

 showed that in fevers, especially typhus, the mortality is 

 f;ir less when the patients are supported with milk and 

 not with alcohol. Quackery and humbug meet with but 

 little mercy at the author's hands, and the hollowness of 

 the pretensions of homoeopathy is well brought out in an 

 essay contributed thirty years ago, which is reprinted in 

 this collection. 



The volume should meet with a large circle of readers 

 outside the medical profession, as it is eminently read- 

 able and touches upon many points in the past history 

 of medicine as well as in modern practice, which are of 

 interest to all. 



Materials for a Flora of the Malayan Peninsula. Part I. 

 By Dr. George King, F.R.S., Calcutta. Pp. 50. 

 (Reprinted from the Journal of the Asiatic Society oj 

 Bengal, 1889, No. 4.) 



Sir J. D. Hooker's " Flora of British India," of which 

 five volumes out of seven are now printed, marks an era 

 in tropical botany, inasmuch as it will probably contain 

 descriptions, with their synonymy, of half the tropical 

 plants of the Old World. It furnishes, therefore, a broad 

 platform for his successors to build upon. It is not likely 

 that within the bounds of India proper many new plants 

 still remain to be described ; but it is not so in the 

 wonderfully rich flora of the Malay peninsula. During 

 the last ten years large collections have been accumu- 

 lated at Calcutta from this region, gathered mainly by 

 Scortechini and other collectors who have been sent 

 out by the authorities of the Calcutta Botanic Garden. 

 In the present pamphlet, which is reprinted from the 

 Journal of the Asiatic Society of Bengal, Dr. King, the 

 Director of the Calcutta Garden, begins a synopsis of the 

 plants which are indigenous to the British provinces of 

 the Malay peninsula, including the islands of Singapore, 

 Penang, and the Nicobar and Andaman groups. 



In this present paper he deals with the orders Ranun- 

 culaceas, Dilleniaceae, Magnoliaceae, Menispermaceae, 

 Nymphasaceas, Capparideae, and Violaceae, leaving over 

 the intricate and largely represented order Anonaceas for 

 another time. In these seven orders there are 35 Malayan 

 genera and 90 species, of which 32 are here described for 

 the first time. Amongst the novelties are included a 

 Magnolia, a Manglietia, 3 Talaumas, an Illicium, 4 species 

 of Capparis, and no less then 1 1 new Alsodeias. Besides 

 the species here described for the first time, there are 

 several others, known previously in Java and China, 

 which are new to British India. It will be seen that the 

 work will add materially to our knowledge of Indian 

 plants, and it is to be hoped that Dr. King, in the midst 

 of his multifarious official duties, may be able to go on 

 with it quickly and steadily. It is hardly worth while, 

 we think, in a series of papers of this kind, to take up 

 space and time by recapitulating in detail the characters 

 of the orders and genera, as, from the nature of the case, 

 it is essentially a supplement to Hooker's " Flora of 

 British India," in which they are already fully worked 

 •out. J. G. B. 



LETTERS TO THE EDITOR. 



[ Tht Editor does not hold himself responsible for opinions ex- 

 pressed by his correspondents. Neither can he undertake 

 to return, or to correspond with the writers of, rejected 

 manuscripts intended for this or any other part of NatuRK, 

 No notice is taken of anonymous communiccUions.\ 



Panmixia. 



Seeing that the whole structure of Prof. Weismann's theory 

 is founded — both logically and historically — upon the doctrine 

 of " panmixia," and seeing that in some important respects his 

 statement of the doctrine appears to me demonstrably erroneous, 

 I propose, to supply a paper on the subject. 



It will be remembered that the principal evidence on which 

 Mr. Darwin relied to prove the inheritance of acquired cha- 

 racters was that which he derived from the apparently inherited 

 effects of use and disuse — especially as regards the bones of our 

 domesticated animals when compared with the corresponding 

 bones of ancestral stocks in a state of nature. Now, in all his 

 investigations regarding this matter, the increase or decrease of 

 a part was estimated, not by directly comparing, say, the wing 

 bones of a domesticated duck with the wing-bones of a wild 

 duck, but by comparing the ratio between the wing and leg 

 bones of a tame duck with the ratio between the wing and leg 

 bones of a wild duck. Consequently, if there l)e any reason to 

 doubt the supposition that a really inherited diminution of a 

 part thus estimated is due to the inherited effects of diminished 

 use, such a doubt will also require to extend to the evidence of 

 a really inherited augmentation of a part being due to the 

 inherited effects of augmented use. Now, there is the gravest 

 possible doubt lying against the supposition that any really 

 inherited decrease is due to the inherited effects of disuse. 

 For it may be — and, at any rate to a large extent, must be — 

 due to another principle which it is remarkably strange that Mr. 

 Darwin should have overlooked. This is the principle of what 

 Prof. Weismann has called panmixia. If any structure which 

 was originally built up by natural selection on account of its use, 

 ceases any longer to be of so much use, in whatever degree it so 

 ceases to be of use, in that degree will the premium before set 

 upon it by natural selection be withdrawn. And the consequence 

 of this withdrawal of selection as regards that particular part 

 will be to allow the part in a corresponding measure to degenerate 

 through successive generations. Weismann calls this principle 

 panmixia, because, oy such withdrawal of natural selection from 

 any particular part, promiscuous breeding ensues with regard to 

 that part. And it is easy to see that this principle must be one 

 of great importance in nature, inasmuch as it must necessarily 

 come into operation in all cases where a structure or an instinct 

 has ceased to be useful. It is likewise easy to see that its effects 

 - — viz. of inducing degeneration — must be precisely the same as 

 those which were attributed by Mr. Darwin to the inherited 

 effects of disuse ; and, therefore, that most of the evidence 

 on which he relied to prove the inherited effects both of 

 use and of disuse is vitiated by the fact that the idea of 

 panmixia never happened to occur to him. In this connection, 

 however, it requires to be stated that the idea first of all 

 occurred to myself, unfortunately just after the appearance of 

 his last edition of the " Origin of Species." I then published in 

 these columns a somewhat detailed exposition of the subject (see 

 Nature, vol. ix. pp. 361, 440, vol. x. p. 164). I called the prin- 

 ciple the cessation of selection — which still seems to me a 

 better, because a more descriptive, term than panmixia — and at 

 first it appeared to me, as it now appears to Weismann, entirely 

 to supersede the necessity of supposing that the effects of use 

 and of disuse are ever inherited in any degree at all. Thus it 

 obviously raised the whole question touching the admissibility of 

 the Lamarckian principles in any case, or the question which is 

 now being so much discussed concerning the possible inheritance 

 of acquired as distinguished from congenital characters. But 

 Mr. Darwin satisfied me that this larger question could not be 

 raised. That is to say, although he fully accepted the principle of 

 panmixia, and as fully acknowledged its obvious importance, 

 he left no doubt in my mind that there was independent 

 evidence for the transmission of acquired characters sufficient in 

 amount to leave the general structure of his previous theory 

 unaffected by what he nevertheless recognized as a necessarily 

 additional factor in it. And forasmuch as no further facts 

 bearing upon the subject have been forthcoming since that time,. 

 I see no reason to change the judgment that was then formed. 



