6io 



NA TURE 



\Oct. 17, 1889 



instance, the b/east and abdomen of woodpeckers are variojsly 

 •coloured, and yet these parts of the body are habitually con- 

 <eaied ; here it is most difficult to conceive how natural selection 

 ■can have bjen the cause of the various modifications. It must, 

 in fact, be admitted that other influences besides natural selection 

 have led to the production of specific characters which are not 

 in any way useful as such. Sexual selection, in the first place, 

 although Mr. Wallace rejects it, must be considered as import- 

 ant. There is an enormous amount of evidence that climate — 

 as we summarize a vast number of external conditions of life — 

 has a uniform and permament influence upon specific characters. 

 A striking evidence of this influence is seen in the faunas of 

 •caves ; here we see a loss of coloration and other peculiarities 

 in the most difl'erent groups of animals. It has been attempted 

 to explain this change as due to natural selection acting directly 

 upon their physiological constitutions, and so indirectly upon 

 their colours. This explanation would be reasonable if only one 

 ■ class of animals were concerned ; but to assume that repre- 

 sentatives of the most diverse classes of animals are acted upon 

 in an identical fashion by natural selection is to assume too 

 -much ; the changes must be due to the direct influence of the 

 environment. Weismann's use of " panmixia," or negative 

 natural selection, to account for such changes, fails, inasmuch as 

 it should also follow that the fauna of the deep sea, which is 

 •exposed to identical conditions as regards darkness, and even 

 temperature, should show an absence of coloration ; but it is 

 notorious that the reverse is the case. Again, the rabbits of the 

 island of Porto Santo, near Madeira, which are the progeny of 

 a few pairs introduced in the fifteenth century, differ in certain 

 'peculiarities of coloration which cannot be regarded as adaptive : 

 in so short a time as four years some of these rabbits, when 

 brought to England, reverted to the original type ; this seems to 

 be the clearest case of the direct influence of climate. Food is 

 knoivnio have a direct influence on coloration, but as yet there 

 is not very much definitely known about these influences ; for in- 

 ■stance, the bullfinch turns black when fed upon hempseed, and 

 other birds change their colour when fed with cayenne pepper ; 

 there can be no doubt that various substances exist in nature which 

 have a similar direct effect upon the plumage of birds which feed 

 'upon them. Isolation is another cause of non-benefioial change. 

 So much, then, for specific characters. If the theory of nitu al 

 selection is good as a theory of the origin of species, it mast 

 .likewise be good as a theory of the origin of genera ; and if 

 specific characters must necessarily all be "useful," so must 

 .generic characters. If the doctrine of utility as universal be c .>n- 

 •ceded to fail as regards genera and all the higher taxonomic 

 -divisions, it appears inconsistent to maintain that it must neces- 

 sarily hold as regards species : it is not supposed to hold as regards 

 •varieties. This seems to be a most illogical position. 



In a paper on the antherozoids of Cryptogams, by Mr. Alfred W. 

 Bennett, the object of the author was to bring out the difference 

 between the two modes in which the ciliated fertilizing organs of 

 Cryptogams are formed, the first type being that which occurs in 

 Vascular Cryptogams, Muscinea;, and Charace^e, the second in 

 Algae (excluding Characese). The essential character of the 

 first type is that the antherozoid is formed from the nucleus only 

 of its mother- cell, the whole of the rest of its protoplasm being 

 consumed in the development of the antherozoid. The vibratile 

 cilia which give to the mature antherozoid its power of rapid 

 •movement proceed from a peripheral layer of hyaline protoplasm 

 belonging to the nucleus. In ferns and other vascular crypto- 

 gams these cilia are very numerous, forming a tuft attached to 

 n.he anterior end of the antherozoid. The antherozoids of 

 MuscinCcE (Musci and Hepaticte) and those of Characete have 

 •only two very long and slender cilia attached in the same posi- 

 tion. The structure and mode of development of these organs 

 is almost identical in these two classes. In the Fucacese, on the 

 -other hand, which may be taken as the highest type of Alga: with 

 ciliated antherozoids, the structure of the antherozoid is alto- 

 gether different. It is a naked cell, not inclosed in a cellulose- 

 wall, with cytoplasm, nucleus, and pigment-spot ; the two cilia 

 both spring from a spot in close proximity to the eye-spot, al- 

 though one of them is attached to the body of the antherozoid 

 •for a portion of its length. The importance of the above facts 

 was pointed out in support of the view that the Characeae are 

 more nearly related to the Muscineae than to the true Algae. 



Mr, Poulton read a paper " On the Sapposed Transmission of 

 Acquired Characters." The position taken up by VVeis.nana is 

 that acquired characters, i.e. characters produced by the in- 

 cidence of external forces upon the iaiivid-ial bj.ly are no: in 



any case inherited. The evidence for such transmission might 

 be direct or indirect ; to the former category would belong 

 transmission of mutilations which would be undoubtedly im- 

 pressed upon the individual body by external influences ; the 

 evidence might also be indirect ; if it could be shown that 

 evolution was impossible without accepting this principle we 

 should have to accept it. The evidence of transmission of 

 mutilations is not strong, and Prof. Windle has argued very- 

 forcibly that monstrosities were due to peculiarities of the ovum 

 and not to external forces. The supposed hereditary effects of 

 use and disuse were unsupported by any proof that the modifica- 

 tions of organs affected by use or disuse had been more complete 

 or more rapid than that of organs not so affected. With regard 

 to instinct. Dr. Romanes had suggested a difficulty — that was, 

 the instinct of certain wasps to sting and paralyze the nerve, 

 centres of their prey. But it must be remembered that the 

 benefits arising from this instinct were felt not by the wasps 

 themselves, but by their progeny. 



The subject was continued by Mr. Francis Gallon, who read 

 a paper entitled, "Feasible Experiments on the Possibility of 

 transmitting Acquired Habits by means of Inheritance," in the 

 course of which he said that feasible experiments have yet to be 

 designed that shall be accepted as crucial tests of the possibility 

 of a parent transmitting a congenital aptitude to his children, 

 which he himself possessed, not congenitally, but merely through 

 long and distasteful practice under some sort of compulsion. The 

 requirements are to eliminate all possibility of parental or social 

 teaching, to bring up all the descendants in the same way, to 

 make simultaneous experiments on many broods during many 

 generations, and, lastly, to economize time, money, and labour. 

 This li.^t of requirements points with emphasis to experimenting 

 on creatures that are reared from eggs, as fowls, fishes, and 

 moths. Fowls. — The largely extending practice of hatching eggs 

 in incubators r)r commercial purposes, and the varied aptitudes 

 of poultry, make them very suitable subjects. Birds are s'aid to 

 have an instinctive dread of various insects ; hence mimetic 

 insects, that are really good for food, are avoided by them. Do 

 such insects exist, and could they be easily reared, which poultry 

 would avoid at first, though experience would soon teach them 

 to like and to eat greedily ? Similarly as regards sounds t.nd 

 cries, which would frighten at first, but afterwards be welcomed 

 as signals for food, &c. Would the stocks of two breeders, one 

 of whom adopted such experiments as these and the other did 

 not, differ in instinct after many generations? Fish. — The ex- 

 periment (quoted by Darwin) of Mobius with the pike, using a 

 trough of water divided by a glass plate into two compartments, 

 in one of which was the pike and in the other were minnows, 

 was mentioned as an example. The pike, after dashing at the 

 minnows many times, and each time being checked and hurt by 

 the glass plate, during some weeks, finally abandoned all at- 

 tempts to seize them, so that when the plate was removed the 

 pike never afterwards ventured to attack the minnows. The 

 question, then, is, whether fish reared for some generations under 

 conditions which compelled them to adopt habits not conform- 

 able to their natures would show any corresponding change of 

 instinct. Of course each generation would be reared in a 

 separate tank from its parents. Moths. — Experiments have been 

 made for the author by Mr. Frederic Merrifield with Selenia 

 illustraria, which has two broods yearly. They are being made 

 for quite another purpose, but have already shown the ease of 

 breeding hardy moths on a large scale when the art of doing so 

 is well understood. All larva- are fastidious in their diet, but it 

 may well be that certain food which they would not touch at first 

 would after a while be greedily eaten, and be found perfectly 

 wholesome. Ezperiments on the lines here suggested ought to 

 show the proportion of cases in which acquired aptitudes of 

 several kinds are certainly not inherited. They might also, per- 

 haps, show tha; in a small proportion of cases ihey cdriainly are. 

 Thus limits would be fixed within which doubt remained per- 

 missible. The object of this paper is to invite experts to discuss 

 the details of the most appropriate experiments. 



Prof. F. O. Bower read a paper on the meristems of ferns as 

 a study in phylogeny. The author has found as the result of 

 examination of the growing points of root, stem, leaf, and of the 

 sporangium in a considerable number of ferns, that as regards 

 their complexity of structure these plants form a natural series, 

 starting from the filmy ferns, which are the simplest, and pro- 

 ceeding through the Polypodiacese and Osmundaceae to >,the 

 Marattias : in the latter the whole structure of the meristems, as 

 well as of the mature organs of the spo.ophyte, is bulky and 



