520 



NATURE 



\Oct. 29, 1874 



LETTERS TO THE EDITOR 



\The Editor docs not hold himself responsible for opinions expressed 

 by his correspondents. Aeither can he undertake to return, 

 or to correspond with the writers of, rejected manuscripts. 

 No notice is taken of anonymous communications.^ 



Automatism of Animals and Men 



I WAS surprised to see by Mr. Wallace's letter of last week 

 that he and I had understood Prof. Huxley's address in senses 

 entirely different. I understood Prof. Huxley to mean that not 

 only the reflex action of animals, but also all the conscious, so- 

 called voluntary actions of men — those, for example, that we 

 perform for the first time and, as we say, with a conscious end 

 in view — are purely automatic ; that is, that consciousness, while 

 it accompanies the workings of the animal machine, never stands 

 in a causal relation to any movement whatever ; that no move- 

 ment ever was the result of a slate of consciousness, that every 

 movement is the result of physical antecedents which, being pre- 

 sent, the movement must of necessity follow, and that in this 

 physical chain there is no break whatever. Years ago I saw no 

 escape from this conclusion, and I have repeatedly made explicit 

 statements of it in the pages of this journal and elsewhere. I 

 was therefore gratified to find Prof. Huxley agreeing with the 

 doctrine ; and that the Lritish public should be so litde startled 

 by his announcement of an opinion whicli has seemed absurd to 

 almost everyone to whom I have atlempted to expound it, struck 

 me as rather curious. Eut the explanation is easy, if a man of 

 such fine and cultured intellect as Mr. Wallace could so com- 

 pletely miss the meaning of Prof, pluxley's discourse. 



Douglas A. Spalding 



The Edible Frog 



Your correspondent Mr. Miller (vol. x. p. 4S3), will find, in 

 Cooke's " British Reptiles," p. 103, accounts of other endeavours 

 to naturalise Kana esculcnta. About ten years ago I imported a 

 basket full from the Parisian fish-market, where they can easily be 

 obtained, and turned them out into a pond at Woburn Abbey, in 

 Bedfordshire. They thrive<l and multiplied there ; but our 

 summers are seldom hot enough to enable the tadpole to attain 

 his full development before the cold autumnal nights set in. 

 Last week, for example, I forwarded to Prof. Huxley a living 

 tadpole of R. esculcnta, born in Bedfordshire, who will scarcely 

 complete his evolution before the winter, though his hind legs 

 are fully developed. ] have several summers, however, ob- 

 served a plentiful supply of young csculcnt,r, and 1 believe that in 

 our climate the young will pass the winter as tadpoles, and 

 complete their iranslormation in the following spring. But this 

 would require more accurate oliservation beiore I can affirm it 

 with certainty. During the past summer 1 imported from 

 Berlin a fresh supply of 200 exceedingly fine specimens, as my 

 French frogs haa been reduced in numbers after the Irequent 

 visits of a heron. K. esculcnta is easily imported in the spring, 

 and will travel many days packed in damp moss. These frogs 

 are easily preserved, being more aquatic in their habits than our 

 J\. tonporaricc, who roam through the woods and meadows in 

 seaich ol food when the breeding season is over, while the edible 

 tiog remains on the banks of his native pond, into which he 

 plunges, describing a f,raceful curve, at the slightest approach of 

 danger. They have been introduced into Ireland quite lately, 

 liora P'rance, by the Earl of Gianard, at Castle Porbes ; wiih 

 what success I am unable yet to say. In the spring any number 

 can be easily obtained from the Parisian market, or the aquarium 

 shop ot M. Carbonier, 20, Quai dii Louvre, Paris; or liom the 

 keeper of the reptiles in the Jaidin des Plantes, who always has 

 a plentiful supply to feed his snakes. 



'Phe laboratories of our lecturers on physiology are supplied 

 flora Leipzig, annually, with living J\. esculcnicc, and Mr. Miller 

 can easily obtain the address of the dealers who export them. 



Uct. 26 Arthur Kussi;i,l 



Colour in Flowers not due to Insects 

 From Mr. F. T. Mott's letter, in your Last issue (p. 503), I 



can hardly imagine him to be acquainted with the literatuie of 



ihe subject on which he writes. The difficulties he suggests, 



though great, arc, I think, not unanswerable. 



I. Cultivation seldom greatly ahects the size or colour of the 



first cultivated individual. In the cases in which it does so, Mr. 



Darwin considers the origin of the variation to be due, as 



suggested by Knight, to change, or excess in food (" Origin of 

 Species," chap. 1.) Where the variation is at first slight and 

 slowly intensined, this is the result of artificial selection. 



2. When we consider the exhausting character of the repro- 

 ductive process, we may perhaps think that the abortion of the 

 sexual organs by the multiplication of phyllfe is the result of 

 weakness ; but a high state of cultivation, or any excess of food, 

 predisposes to the degradation of organs, the excessive growth 

 of parenchyma, rapid growth, and disease. Organs are also 

 absorbed by heat or by frost. As to the perpetuation of such 

 forms, Mr. Darwin instances ("Origin of .Species," chap, viii.) 

 some varieties of the annual stock which produce both double 

 sterile and single fertile seedlings, justly comparable to the fertile 

 and neuter forms of social insects. 



3. 'Phe " abortive flowers " ot such umbellate and capitulate 

 infiorescences as the Guelder Rose, Hydrangea, and Centaurea, 

 where not effected by artificial selection, act as a lure to the 

 central ferti e florets, as shown by Dr. Ogle (J'opular Science 

 Kei'itw, April 1670), originated according to the law of balance 

 ot growth. 



4. The beauty of fruits "serves merely as a guide to birds 

 ana beasts, in order that the fruit may be devoured and the 

 manured seeds disseminated" ("Origin of Species, "chap, vi.) 



5. " We meet very commonly with gaily-coloured chemical 

 products, essentially connected with the normal processes of 

 development, and originating from venomous infection by insects, 

 or from decomposition. These colours appear to be merely an 

 accidental quality of the chemical products . . . natural selec- 

 tion is witnout any influence as to colours, unless animals are 

 attracted or repelled by them" (Hermann Miiller : Nature, 

 vol. ix, , p. 460). Mimicry has been recorded in fungi 

 (Nature, vol. vii. p. 55). Mr. Mott's letter indicates the 

 fallacious opinions that mere beauty or variety are objects in 

 nature, and that the Darwinian hypothesis deals with the origin 

 of variations. G. S. Boulger 



Harrow Road, W., Oct. 26 



Abler pens than mine will probably reply to Mr. Mott's 

 letter in Nature, vol. x. p. 503 ; but if not, may I be permitted 

 to point out that the facts therein adduced, as not harmonising 

 with the theory that colour in flowers has been assumed for the 

 purpose ol attracting insects, are capable of explanation. 



1. Cultivated /Icnocrs. — 'ihe greater size and brilliancy of colour 

 attained by these is not due to cultivation alone, but to selection 

 practised by the cultivator. He chooses his seeds from the 

 plants that bear the largest and best coloured flowers, and thus, 

 directly and intentionally, performs the very work that in a state 

 of nature is carried out, indirectly and unconsciously, by the 

 insect fertiliser. 



2. Double Jhrwcrs are only accidental, and not permanent, in a 

 state of nature. The cultivator has succeeded in producing and 

 preserving them by giving a preference to, and propagating from, 

 tfioie plants which bear flowers with a tendency to become 

 double. Here also intentional selection by the gardener has 

 taken the place ot natural selection by the insect. 



3. 'Phe ubortiz'c Jloiocrs of the Guelder Rose and Hydrangea, 

 as they grow naturally, are confined to the outer part of che 

 corymbs, and serve the same purpose as the ray ol Composii.'e 

 (which in some species consists of neuter florets) and the highly 

 coloured floral bracts of some plants, viz., to attract insects to 

 the fertile flowers they surround. 'Phe garden forms of Viburnum 

 and Hydrangea, the corymbs ot which are composed entirely or 

 neaily so of sterile flowers, are, like double flowers, the result of 

 intentional selection by the cultivator. 



4. 'Phe brilliant colours of many succulent fruits have resulted 

 from their superior attractiveness, i\.x indeed to insects lor the 

 purpose of fertilisation, but to birds and other fruit-eating animals 

 lor the purpose ol dissemination, as has been well described by 

 I'lol. Hildebrand. 'Phe occurrence of brilliant colours in the 

 vegetable kingdom, independently of the agency ol insects, as on 

 iruits, galls, lungi, and lichens, is no more irreconcileable with 

 the theory that tfie colour of llo'ivcrs has been brought about by 

 that agency, than is the occurrence of bright colours on insects 

 themselves and other members of the animal kingdom, or the 

 vivid colour of many mineral substances. 



Newion-le-Wiiluws, Oct. 20 Thomas Comber 



Migration of Birds 

 I llAVi; waited for some time to see if anyone would ask Prof. 

 Newton or Mr, 'Pegetmeier, on what evidence the latter gentle- 



