Dec. 24, 1874J 



NA TURE 



149 



natural selection by insects, because the spots and streaks of 

 flowers are much less sharply defined. 



2. Why is ornamental colouring, as a rule, confined to the 

 male? If the love of beauty is an animal instinct, why, on 

 Darwinian principles, is not beauty developed in the females, the 

 most beautiful females being the most likely to obtain mates and 

 leave offspring ? I speak chiefly of birds. 



3. Is there any reason to believe that the female has any choice 

 or power of selection whatever ? I think that what evidence we 

 have goes to prove that she is passive : and certainly this opinion 

 is supported by the very general fact of the males fighting for the 

 possession of the females. 



If the love of beauty is an animal instinct, then Darwinian 

 principles would require that the struggles of the males for the 

 possession of the most beautiful females should develop beauty 

 in the females by natural selection. But vre see that the contrary 

 is what takes place — beauty is developed in the male, the 

 fighting sex. 



Were a Darwin among birds to watch the ways of the human 

 race, he would probably feel certain that the love of dress and 

 ornament among women is altogether due to a desire to become 

 attractive to men ; and he would think those naturalists unsatis- 

 factory, and perhaps mystical, who guessed the truth, that the 

 love of ornament is a naturil and healthy human instinct, not 

 confined to either sex or to any age, but stronger in youth than 

 in age, and stronger in woman than in man. 



Joseph John Murphy 



Old Forge, Dunmuiry, Co. Antrim 



Psychology of Cruelty 



There is a passage in Mill's recently published essay 

 on " Nature " whicli well merits the attention of evolutionary 

 psychologists. It is as follows : — "Again, there are persons who 

 are cruel by character, or, as the phrase is, naturally cruel ; who 

 have a real pleasure in inflicting, or seeing the infliction of pain. 

 This kind of cruelty is not mere hardheartedness. or absence of 

 pity or remorse ; it is a positive thing ; a particular kind of 

 voluptuous excitement. The East, and Southern Europe, have 

 afforded, and probably still afford, abundant examples of this 

 odious propensity." (P.ige 57.) 



Now, I think that this "hateful propensity" is of more com- 

 mon occurrence than even Mr. Mill here gives it credit for. 

 Indeed, I doubt whether anyone is entirely devoid of it, although, 

 of course, everyone who is sufficiently advanced in moral culture 

 to admit of the subordination of the baser instincts to the higher, 

 has been more or less successful in "starving it by disuse." I 

 believe, in short, that this propensity must be regarded as one 

 of the primary instincts of our nature, although, like other 

 instincts, it varies in its original intensity in different individuals, 

 and is further differentially modified by the various influences of 

 education. The nature of this instinct is well expressed by Mr. 

 Mill in the above-quoted phrase, "a particular kind of volup- 

 tuous excitement." This, I think, supplies the reason why it is, 

 as a rule, of stronger development in men than in women, and 

 why, as Mill observes, it is of most frequent manifestation in 

 warm climates. It is also worth observing, that although thus 

 akin to the amatory passion, it is of much earlier growth in the 

 life-history of the individual. Indeed, childhood and youth are, 

 in civilised society at least, the seasons when its presence is 

 most conspicuous ; in consequence, I suppose, of the restraining 

 power which reflection subsequently brings to bear upon it not 

 as yet having been called into action. 



To explain the origin of this instinct by the evolutionary 

 psychology is, I believe, impossible in the present state of our 

 knowledge; for there is no period in the history of the race at 

 which it IS conceivable that the latter should have derived any 

 benefit from the birth and development of this peculiar passion. 

 Yet I believe it is now in some persons, were it permitted to assert 

 itself, of even more intensity than is the highly beneficial inclina- 

 tion to which, as we have just seen, it is so strangely allied. To 

 refer to the striking similarity of this passion in man to that which is 

 manifested by monkeys, is not of course to explain its origin ; 

 but I am quite sure it is in the monkeys that this explanation is to 

 be sought. Everyone knows that these animals show the keenest 

 delight in torturing others simply for torturing sake, but every- 

 one does not know how much trouble an average monkey will 

 put himself to in order that he may gratify this taste. One 

 example will suffice. A naturalist who had lived a long time in 

 India told me that he has not unfrequently seen monkeys 



feigning death for an hour or two at a time, for the express 

 purpose of inducing crows, and other carnivorous birds to 

 approach within grasping distance ; and when one of the ia'tter 

 were caught, the delighted monkey put it to all kinds of agonies, 

 uf which plucking alive seemed to be the favourite. 



As I am not aware that any other animal exhibits this instinct 

 of inflicting pain for its own sake — the case of the cat with a 

 mouse belonging, I think, to another category — I believe, if its 

 origin is ever to receive a scientific explanation, this will be 

 found in something connected with monkey-life. 



Physicus 



Migration of Birds 



Yesterday and to-day (17th and i8th inst. ) continuous 

 flights of migrant birds, chiefly fieldfares and redwings, have 

 passed over this place in one uniform direction, from east to 

 west, turning inland to the north-west, as though unwilling 

 to cross Poole Harbour. The procession, so far as it attracted 

 my own notice, began with daybreak of the 17th, and was so 

 rapid and continuous all that day that enormous numbers alto- 

 gether must have passed over us. Close flocks would come, and 

 then a continuous flight of stragglers, but all in one and the 

 same direction, and with little deviation from a well-defined 

 atrial pathway, as though keeping some visible high-road. 

 Yesterday the flight was down the wind ; this morning against 

 it ; and although the flight was low and the birds seemed tired, 

 none alighted in this neighbourhood. Whence did they come, 

 and whither are they bound — east or west of this place ? Can 

 any of your readers say ? H. C. 



Bournemouth, Dec. 18 



The Potato Disease 



In his letter of last week. Prof. Dyer states that his main 

 object in his previous letter was "to claim for a distinguished 

 English botanist credit for work done by him thirty years ago." 

 In his previous letter this work is defined by Prof. Dyer to be 

 the discovery by the Rev. M. J. Berkeley of the fact that the 

 potato disease was due to the attacks of a parasitic fungus. As 

 the service, with which botanists are familiar, that Mr. Berkeley 

 has rendered in this matter, is the publication and .-idvocacy in 

 this country of the discovery previously made by Montague and 

 others, with a few additional observations of his own. Prof. 

 Dyer would confer a favour on his fellow-botanists by giving 

 a more exact reference to the records which he is so anxious 

 should be duly recognised. Inquirer 



HELMHOLTZ ON THE USE AND ABUSE OJ^ 

 THE DEDUCTIVE METHOD IN PHYSICAL 

 SCIENCE* 



SINCE the translation ol the first part of this volume 

 was published, its whole scientific tendency, and 

 specially a series of individual passages in it, have been 

 subjected to a more than vigorous criticism by Mr. 

 J. C. F. Zollner in his book " On the Nature of Comets.'' 

 I do not think it necessarj' to answer expressions of feeling 

 in reference to personal characteristics of the English 

 authors or of myself. I have as a rule considered it 

 necessary to reply to criticisms of scientific propositions 

 and principles only when new facts were to be brought 

 forward or misunderstandings to be cleared up, in the 

 expectation that, when all data have been given, those 

 familiar with the science will ultimately see how to form 

 a judgment even without the discursive pleadings and 

 sophistical arts of the contending parties. If the present 

 treatise were intended only for fully educated men of 

 science, Zollner's attack might have been left unanswered. 

 It is, however, essentially designed for students also, and 

 as junior readers might perhaps be misled by the extreme 

 assurance and the tone of moral indignation in which 

 our critic thinks himself justified in expressing his 

 opinions, I consider that it would be useful to answer the 

 attacks made on the two English authors, so far as may 



* Translated by Prof. Crum Blown from Helmholtz's preface to the 

 second part of the German edition of Thomson and Tail's " Natural Philo- 

 ophy," vol. i. 



