April 2 \, 1879] 



NATURE 



581 



Lucien Bonaparte, puts it next to the West African Buphagtz. 

 Now the Buphagcc are certainly dull birds, while Scisstrostriim 

 is described in the " Malay Archipelago " as "almost entirely 

 of a slaty colour, with yellow bill and feet, but the feathers of 

 the rump and upper tail-coverts each terminate in a rigid glossy 

 pencil or tuft of a vi\-id crimson" (i. 430). I wrote -nnth this 

 passage of Mr. Wallace's under my eyes, and refer in a footnote 

 to his volume for the vivid crimson. I did not say the bird 

 was brilliant, I merely noticed the colour of its tail and beak. 

 The case really stands thus : If Scissirostrum was differentiated 

 from a generic ancestor generally resembling Buphaga, we have 

 to inquire, why did it develop these ornamental adjuncts ? and 

 my answer is, because while Buphaga pecks the parasites of the 

 backs of mammals, Scissirostrum feeds oflf "grains and fruits." 



2. "Santarem, of which it is said 'the pastiires are destitute 

 of flowers, and also of animal life, with the exception of a few 

 small plain-coloured birds,* is one of the richest localities for 

 flowering shrubs in South America." Now, this passage to 

 which Mr. Wallace takes exception is not mine, but is a textual 

 quotation from Mr. Bates ("Naturalist on the Amazons," 

 p. 183). It is given in inverted commas in my text, with 

 reference to the original in a footnote. I was, of course, aware 

 that the Brazilian woods generally were full of brilliant birds, 

 and that "the butterflies in the adjacent forests were gorgeous in 

 the extreme." What I wished to point out was that in particular 

 spots like these meadows, where the general aspect of the flora 

 was not bright, the purely local fauna was likewise dulL We 

 may find great varieties in this respect nearer home in a meadow, an 

 adjacent warren, and a moor or swamp behind it. Moreover, 

 the passage was professedly quoted, simply as showing the 

 general impression left upon my mind by reading various books 

 of travel. May I add a sentence from a private letter of Mr. 

 Darwin's, which helps out the same view on a larger scale ? 

 "The contrast," he says, "in the colour of the birds in 

 Pat^onia " (where he had just noticed "the sombre aspect of 

 nature"), "and on the bright green flower decked plains of 

 La Plata is very striking." 



3. About a certain squirrel, described in the " Malay Archi- 

 pelago " as ha^-ing a tail "ringed with gray, yellow, and brown," 

 and as looking " exceedingly pretty," Mr. Wallace now says it 

 " is one of the dullest of the group," while he did not "say a 

 word about its feeding on ' bright-coloured fruits.' " But he 

 </»i/ say that it would eat "any fruit" (i. 192), and I presume, 

 therefore, that it sometimes eats " bright coloured food." 



4. "So far from the colours of caterpillars being 'mostly 

 protective,' every entomologist knows that a large number of 

 caterpillars in every part of the world are conspicuously 

 coloured." True ; but Mr. Wallace himself was the first to 

 suggest that these conspicuous colours were themselves protective 

 by giving warning of inedibility ; and I am at a loss to under- 

 stand what he means by thus going back upon his own words. 

 I took my statement from Sir John Lubbock's lecture "On 

 Certain Relations between Plants and Insects," pp. 23-24, where 

 this fact of universal protective colouring in lar\ae is very clearly 

 brought out. 



5. "Again, the ground-feeding pheasant family are passed 

 over as containing only one brilliant bird, the peacock, whereas 

 it abounds in species of the most gorgeous colour." But my 

 words are very difierent from this — " Even among the pheasants 

 themselves," I say on p. 176, "many specie- are far from 

 brilliant ; and when we come to compare the whole family with 

 that of the parrots or the humming-birds, we shall find that the 

 peacock alone can fairly come into competition with the typical 

 fruit-eaters and flower-feeders." Mr. Wallace goes on to men- 

 tion (amongst others) the "Impeyan pheasant of the Hima- 

 layas," and "the intensely -brilliant fire-backed pheasants of the 

 Malay countries," as among the most brightly-coloured species. 

 Any one would suppose from his review that I had totally over 

 looked these cases ; but in the very same paragraph with the 

 sentence which Mr. Wallace blames the following passage 

 occurs : — " The forests of the Himalayas and the Malay Archi- 

 pelago, with their great brilliant fruits and flowers, aid their ex- 

 quisite insects, form the haunts of the most beautiful species of 

 pheasants" (p. 177). As a matter of fact, before writing that 

 paragraph I had carefully compared all the livinof phasianidce in 

 the Zoological Gardens, and all the preserved specimens in the 

 British and Oxford Muesums ; and I feel sure that any one who 

 does the same \^ ill agree with me that the peacock alone can be 

 placed in the very first rank of brilliant colouration. 



6. How much the subjective element enters into these ques- 



tions may be seen from the following remark of Mr. Wallace : — 

 " The tigers, the zebras, the beautifully -marked antelopes, and 

 the spotted deer and giraffes, whick are really among the most 

 brightly-coloured of all mammals, are passed over as less beauti- 

 fully coloxired than the squirrels and monkeys." Now I confess 

 myself simply astounded at the statement that the zebra, of all 

 animals in the world, is brightly coloured — a creature without a 

 tinge of anything but creamy white and black about its body. 

 Quite apart from the nature of food or surroundings, I call a 

 panda a brightly-coloured mammal ; or a mandrill ; or a Rhesus 

 monkey ; or a Canadian chipmonk ; but certainly not a tiger, a 

 zebra, or a giraffe, none of which has a single tinge of scarlet, 

 blue, green, or bright yellow. 



No one who knows anything of Mr. Wallace could for one 

 moment imagine him capable of intentionally misrepresenting 

 the humblest opponent in the smallest particular ; and I owe 

 him many thanks for much kind and appreciative criticism both 

 on this and several previous occasions. Yet I cannot help think- 

 ing that in these instances, and others with which I will not 

 burden your space, he has unconsciously permitted mere diflfer- 

 ences of opinion unduly to assume the appearance of positive 

 errors in fact. Grant Allen 



Remarks by the Reviewer 



1. Scissirostrum Pagei is universally placed in the starling 

 family. Its affinity to Buphagu is very doubtful, while its crim- 

 son-tipped tail-coverts are very different from "a tail of vivid 

 crimson" which Mr. Allen gives it (p. 184). 



2. I object altogether to founding theories on chance ex|»:«s- 

 sions of travellers. It is curious, that in my "Travels on the 

 Amazon" (p. 157) I refer to these same Santarem pastures as 

 follows: — " There were some boggy meadows here, more like 

 those ' of Europe than one often sees so near the equator, on 

 which were growing pretty, small Melastomas and other flowers. 

 The paths and campos were covered with flowering myrtles, tall 

 Alelastonias, and numbers of passion-flowers, convolvuluses, and 

 bignonias." These open meadows and campos really exhibited 

 more conspicuous flowers than the woods and forests which 

 swarmed with brilliant butterflies and birds. 



3. I referred to the squirrel, because it was the only example 

 given by Mr. Allen which I could at the moment test. 



4. My argument is, that the colours of caterpillars are often 

 as varied, as ^'ivid, and as beautifully arranged as in birds and 

 winged insects. This is not necessary for protection by conspicu- 

 ousness, for which purpose any tint contrasted with foliage, such 

 as black, or white, or ringed with black-and-white, would have 

 sufficed. 



5. The "pheasant" question I leave, as Mr. Allen has placed 

 it, for the consideration of naturalists. 



6. Here it seems to me Mr. Allen is himself changing his 

 ground. His main argument is that the aesthetic tastes of the 

 higher animaLs are the same as ours, yet he objects to the ele- 

 gantly-marked and intensely-contracted zebra and tiger being 

 called " brightly- coloured." Surely they are more beautiful than 

 the mandrill or the Rhesus ; while among animals white is as 

 much a colour as among flowers. Alfreb R. Wallace 



Nitric Acid Batteries 



I INCLOSE the results of some experiments I have lately made 

 to ascertain if the cost of working the nitric acid batteries of 

 Grove and Bunsen could be reduced. I find that the nitric acid 

 can be replaced by a mixture of half nitric and half dilute 

 sulphmic. And the latter gives a higher force for nearly three 

 hours. The experiments were made with a large-surface volta- 

 meter, and the gases were collected during one minute every 

 half-hour ; four pint -size cells were used. The experiments were 

 repeated, and every care taken to avoid any error. I have also 

 used the mixed acids very successfully with twenty-eight cells for 

 the electric light. I presume the increased power is due to the 

 internal resistance of the battery being slightly lowered by 

 the addition of the dilute sulphuric acid in the porous celL I 

 may add that the fumes were much less than when nitric acid 

 alone is used. John Henry Knight 



Famham, April 19 



The Black Rat 



In regard to the distribubution of the black rat {^Mus rattus), 

 your correspondent may be glad to know that this animal, spread 



