3?o 



NATURE 



{August 1 6, 1888 



of fungi belonging to the same genus as the one we have 

 been considering, or else to the closely allied genus 

 Pythium. In illustration of this I will mention one case 

 only. 



It is always possible to obtain well-grown specimens of 

 the fungus Pythium by sowing cress seed fairly thick, and 

 keeping the soil well watered and sheltered. Now what 

 does this mean ? Nobody imagines that the fungus arises 

 spontaneously, or is produced in any miraculous manner ; 

 and in fact we need not speculate on the matter, for the 

 fact is that by keeping the crowded cress seedlings moist 

 and warm we favour the development of the Pythium 

 (spores of which are always there) in somewhat greater 

 proportion than we do the development of the cress. In 

 other words, when the cress is growing normally and 

 happily under proper conditions, it is not because the 

 Pythium is absent, but because (under the particular 

 conditions which favour the normal development of 

 healthy cress) it grows and develops spores relatively 

 so slowly that the young cress seedlings have time to 

 grow up out of its reach. The recognition of this struggle 

 for existence on the part of seedlings is of the utmost 

 importance to all who are concerned with the raising of 

 plants. H. Marshall Ward. 



NATURAL SELECTION AND ELIMINATION} 



MR. DARWIN'S phrase, "natural selection," is ap- 

 plied to such processes, other than those involving 

 the agency of man, as result under Nature in the survival 

 of the fittest. These processes fall under two heads, 

 which have not, I think, been sufficiently distinguished. 

 For the first of these I here retain the word selection; for 

 the other I suggest the term elimination. 



In natural selection the favourable varieties are chosen 

 out for survival : in natural elimination the failures or 

 comparative failures are weeded out. In the one, Nature 

 is employing conscious agents upon the upper or superior 

 end of the scale : in the other, Nature is, through con- 

 scious or unconscious agencies, at work on the lower or 

 inferior end of the scale. 



Variation is constantly taking place ; and the varia- 

 tions may be favourable or unfavourable or neutral. 

 Under selection the favourable variations will be chosen 

 out ; the unfavourable and the neutral may go. Under 

 elimination the unfavourable disappear ; the favourable 

 and the neutral remain. By how much the favourable 

 variations are in excess, by so much will the race tend to 

 advance. I see no reason why neutral variations should 

 be eliminated, except in so far as — in the keen struggle 

 for existence — they become relatively unfavourable. 



In the valuable and suggestive paper in which Mr. G. 

 J. Romanes dealt with physiological isolation, he brought 

 forward the inutility of specific characters as one of the 

 three cardinal difficulties in the way of natural selection 

 considered as a theory of the origin of species. So long 

 as we consider selection proper, this objection is valid. 

 But under elimination (by far the more potent of the two) 

 there is no reason why specific features without utilitarian 

 significance should be weeded out. Undoubtedly, in the 

 long run, useful variations will tend more and more to 

 preponderate, since, the longer and keener the struggle, 

 the greater the tendency for neutral variations to become 

 relatively unfavourable. And this conclusion is in har- 

 mony with the teachings of biology. For, as Mr. Romanes 

 remarks, ' ; it is not until we advance to the more import- 

 ant distinctions between genera, families, and orders that 

 we begin to find, on any large or general scale, unmis- 

 takable evidence of utilitarian meaning." 



Natural elimination is intimately associated with the 

 struggle for existence, which may indeed be regarded as 

 the reaction of the organic world called forth by the 

 action of natural elimination. The struggle for existence 



1 Abstract of a Paper read before the Bristol Naturalists' Society. 



is the result of a threefold process of elimination (cf. 

 " Origin of Species," chap. iii.). First, elimination by 

 the direct action of surrounding conditions ; secondly, 

 elimination by enemies (including parasites) ; and, thirdly, 

 elimination by competition. 



Natural selection (in the narrower sense suggested) is- 

 a much rarer process, and one that only comes into 

 play when intelligence, or (since it may be objected 

 that selection is in some cases instinctive) when the 

 mind-element comes definitely upon the scene of life. 

 Perhaps one of the best examples is the selection of 

 flowers and fruits by insects and fruit-eating animals. 

 But even here (at least in the case of flowers) the process 

 of elimination also comes into play : for the visitation of 

 flowers by insects involves cross-fertilization, the advant- 

 ages of which Mr. Darwin so exquisitely proved. So 

 that we have here the double process at work, the fairest 

 flowers being selected by insects, and those plants which 

 failed to produce such flowers being eliminated as the 

 relatively unfit. 



If we turn to the phenomena of what Mr. Darwin 

 termed " sexual selection," we find both selection and 

 elimination brought into play. By the law of battle the 

 weaker and le^s courageous males are eliminated, so far 

 as the continuation of their kind is concerned. By the 

 individual choice of the females, the finer, bolder, hand- 

 somer, and more tuneful wooers are selected. 



When we have to consider the evolution of human folk, 

 the principle of elimination is profoundly modified by the 

 principle of selection. Not only are the weaker elimin- 

 ated by the inexorable pressure of competition, but we 

 select the more fortunate individuals and heap upon them 

 our favours. This enables us also to soften the rigour of 

 the blinder law ; to let the full stress of competitive 

 elimination fall upon the worthless, the idle, the profli- 

 gate, and the vicious ; but to lighten its incidence on the 

 deserving but unfortunate. 



It is my belief that our views of evolution gain in clear- 

 ness by the separation of these two processes by which 

 the survival of the fit is brought about. Whether the 

 use of the term " natural elimination " alongside of and in 

 subservience to " natural selection " would be of service 

 to those who are students and teachers of evolution 

 doctrines, I must leave others to judge. 



C. Lloyd Morgan. 



THE FAUNA AND FLORA OF THE LESSER 

 ANTILLES. 



ALTHOUGH much has been done of late years, both 

 in the United States and in Europe, towards the 

 investigation of the fauna and flora of the smaller West 

 Indian Islands, or Lesser Antilles, as it is better to call 

 them, much remains to be effected before we can be 

 deemed to have an accurate knowledge of the natural 

 products of these islands. And it is most important that 

 steps should be taken to remedy this deficiency without 

 further delay. As the tide of civilization advances — more 

 slowly, perhaps, it is true, over these islands than in 

 many other parts of the world's .surface — the special 

 peculiarities which each individual isla nd possesses 

 among its animal and vegetable indigens are fast 

 becoming overwhelmed by the more powerful animals 

 and plants that accompany the inroads of civilized man 

 upon the wilderness of Nature. As in other places, 

 where settlers from Europe arrive, rats and mice eat out 

 the indigenous animals, and exotic weeds starve out the 

 native plants. It is therefore most desirable that, while 

 there is yet time, exact information should be obtained of 

 the flora and fauna of these islands, every one of which 

 seems to exhibit features more or less peculiar to itself. 



This subject having been brought before the Committee 

 of Section D at the Manchester meeting of the British 

 Association by Mr. Sclater, a grant of .£100 was made for 



