August iS, 1879] 



NATURE 



427 



li .use in which I am writing, without interruption, from jy.SO 

 A.M. till dark, and are now at 11.30 P.M., flying in at the open 

 w indow, so as to be a perfect nuisance. They are still tired 

 moths, for they soon settle ; there are certainly many hundreds 

 in the dark corners and along the cornice.^ My children tell me 

 that numbers of the moths were lying dead on the dry sand above 

 high- water mark.- They collected some for a tame young mag- 

 pie, which has been very happy all day among the flower-beds 

 in the garden catching P. gamma, which, under ordinary condi- 

 tions, would be far too wide awake for him. 



How far the flight extended south of Trouville I do not know, 

 but the number of insects which have passed from sea to land 

 here to-day must be very great. Assuming that one P. gamma 

 passed over each metre of shore line each minute, an estimate 

 below the mark at all points to which my observation extended, 

 and assuming the flight to have extended 10 kilometres along the 

 shore, as I ascertained that it did during the evening, nearly 

 8,000,000 of P. gamma passed from sea to land between 7.30 

 A.M. and 8.30 P.M. 



All the i:isects which I caught or looked at on flowers were in 

 perfect condition. 



Where have all these insects come from ? Has the flight been 

 noticed in England? K. ca?-i//«' was exceedingly abundant here 

 in June and throughout July, indeed it was the only butterfly 

 to be seen in any numbers. Its larvje have been feeding in toler- 

 able numbers on the thistles and other plants, and some few 

 fresh specimens appeared before the flight of to-day, but I think 

 there is no doubt the insects which formed to-day's flight were 

 not bred here. Why should the moth and the butterfly come 

 together ? Here they were flying against or nearly against, the 

 wind, although they may have started with a favourable wind. 

 Where will they go to ? If they go far, what influence will they 

 have on cross-fertilisation ? The quantity of pollen which they will 

 carry onwards from the myriads of flowers they have visited will 

 be immense. Perhaps other observers may answer some of these 

 questions. J. Clarke Hawkshaw 



Trouville, Calvados, France, August 12 



P.S. — The flight still continues this morning, August 13, 10 

 A.M. ; V. cardui <\\xAe as abundant as yesterday. 



P. S. No. 2. — The flight of V. cardui and P. gamma, described 

 in my letter of August 12 ceased about 12 A.M. on the 13th. At 

 It A.M. I counted forty-six and twenty-four V, cardui on the 

 shore passing over a space of fifty yards in width, in two intervals 

 each of two minutes. Judging from their number, the V. cardui 

 have not remained here ; on the other hand, I think many of 

 the P. gamma have. On the 14th a large clearing in the forest 

 of Tonques, about two miles inland, was alive with them. The 

 flowers of the wood-sage appeared to be the great attraction 

 there. I noticed many P. gavtma lying dead on the roads inland, 

 all in perfect condition. I believe ,that these moths died of 

 starvation. The moths which flew into the house on the evening 

 of the 1 2th were all more or less sluggish in the morning. There 

 were more than 400 on one window, many of which readily took 

 food offered to them in the form of syrup, and I induced a 

 number of those in the forest to come on to my finger and suck 

 up syrup. 



What I have seen leads me to make the following suggestions 



j as to the cause of these migrations of lepidoptera. 



'i._ When a favourable season produces a great swarm cf insects 



' numbers would die from want of food if they remained where 



they came into existence, as the number of food-producing 



flowers is limited. To move off in some direction would be a 



ni-cessity, and in time the impulse to migrate would become in- 



inctive as soon as the want of food was felt, or even the pre- 



ce of a crowd of their fellows. It would seem that the 



ply of food might be most readily found if the insects moved 



on in all directions, that is, spread from the centre of scarcity ; 



( but many moths seek their food by scent, and on that account 



• generally, I believe, fly against the wind. Many facts might be 



' given to show how acute the power of scent in moths is. 



Whether butterflies seek their food by scent or not I do not 



1 know ; some are certainly attracted by strong odours, Afatura 



! iris, for instance. At any rate, I think a hungry moth woull 



fly against the wind, and so the general direction of a flight of 



moths might be determined. 



Here both butterflies and moths searched the first flowers they 

 came to after leaving the sea. The first comers would go on 



' \ have counted 300 on one p:irt of the cornice. 

 J'ogsibly killed by the heat of the sand, on which they settled in an ex- 

 ited sf-.te. 



refreshed, but the later ones merely wasted their energy in a 

 fruitless search, and many of the moths fell dead by the way. 



In the case of the flight I have described, a double necessity 

 for the migration would have arisen if the butterfly and the 

 moth came into existence at the same time as, seeing their fine 

 condition, they most probably did. As both appeared to search 

 the same flowers, the dearth of food at their centre of departure 

 would more speedily Imve arisen. — J. C. H. 



August 23 



Animal Rights 



Mr. Romanes's parallel is as unsound as amusing. If a 

 physiologist claimed to vivisect his children "on the plea that it 

 was for this purpose that he had begotten them," we should tell 

 him that the legal admission of such pleas would undermine human 

 society. But in the killing of pigs for food no undermining of 

 human society is involved. Moreover, we know that men breed 

 pigs only to kill them, but that men breed children from entirely 

 different motives ; we should answer the physiologist that his 

 plea was impossible of proof, that all human experience nega- 

 tived its probability, and that consequently it could not be 

 admitted to overrule his children's presumptive right of life. 



Mr. Romanes repeats his amazing proposition in morals, that 

 " if we have a moral right to slay a harmful animal in order to 

 better our own condition, it involves an inconsistency to deny 

 that we have a similar right to slay a harmlesss animal, if by so 

 doing we can secure a similar end. " Then, if we have a moral 

 right to slay harmful Zulus to better our own condition, we have 

 a similar right to slay harmless Eskimos, if by so doing we can 

 secure a similar end ! 



Mr. Romanes says that I did not attempt to meet one of his 

 criticisms. Had I thought I might, I would have met them all ; 

 it does not take long. He thinks a lobster, to whom might is 

 right, could not convince a philosopher that the latter had no right 

 to eat him. Then I may pick a thief's pocket ? He next admits 

 that the lobster might appeal to the philosopher's morality, but 

 asks why "the right of an edible animal to live is superior to 

 that of an eating animal to kill ? " Then the right of a robbable 

 man to his money is not superior to the [right of a man who 

 uses money to rob him ? And I, who am edible, have no more 

 right to live than a cannibal has to eat me ? Lastly, Mr. Romanes 

 makes his philosopher say that he prefers lobster salad and roast 

 lamb to boiled snakes and rat pie. Preferences are not rights, 

 but if they were I have not suggested that the latter diet shotild 

 supersede the former ; and so my withers are unwning. 



Edward B. Nicholson 



[Ergo the rights of a pig are not the same as those of a baby, 

 which is just the point which my purposely unsound parallel was 

 intended to show. It is for Mr. Nicholson to prove that the 

 parallel is sound, if he is to sustain his "erroneous premiss," 

 that the rights of men and animals are identical (the objection as 

 to "motive" I ignore, because on the erroneous premiss in 

 question the physiologist's motive might be sincerely stated and 

 adequately pro.ved as a motive by a declaration, say, in the 

 marriage settlements). Instead of doing so, however, he alludes 

 to one important difference between the rights of an animal and 

 those of a man — the difference, namely, which arises from the 

 latter being a member of human society. And this difference is 

 in itself .sulficient to nullify the force of all his rejoinders. Only 

 on Mr. Nicholson's own supposition, that the rights of all living 

 things are identical, could any of my propositions made with 

 reference to animals be tested by their applicability to men. But 

 thLs is just the supposition which I regard as absurd, and because 

 it seems to me that ethical doctrine is here sufiiciently patent — 

 viz., that man as an intellectual, moral, and social being has 

 rights additional to those of a merely sentient being. I will not 

 take any further part in this correspondence.] 



George J. Romanes 



Alpine Clubs 



In your account of the late conference of Alpine clubs, held at 

 Geneva, there is one little omission which, as interesting to the 

 scientific world generally, I beg leave to remedy. 



It was suggested by your humble servant that a republication 

 of de Saussure's "Voyages dans les Aljies" would bean appro- 

 priate memorial of our little congress at the city of which he 

 wa«, I may say yet is, so bright an ornament. My plan was to 



