Sept. 12, 1878] 



NATURE 



523 



lever press, the clear liquid which is expressed being 

 added to that which has been clarified. It is now placed 

 in boilers and heated up to about 60° C, after which it is 

 kept in the store vats, carefully sealed up. 



The residue left in the press is subjected to a process 

 of distillation in a current of steam, by which a spirit 

 containing about 42 per cent, of alcohol is obtained. 



The sakd in the store vats contains about 15 per cent, 

 of alcohol, and this fact shows that the fermentation is 

 different to that effected by the Miicor I'acemosus, as 

 described by Fitz. In his experiments he found that 

 the presence of 4J to 5I per cent, of alcohol killed the 

 ferment, whilst in the process above described, we find 

 the ferment acting in such a way as to produce 15 per 

 cent. There is, however, nothing improbable in the 

 supposition that different species may possess different 

 degrees of sensitiveness to alcohol, and that the species 

 used here may be less easily affected than the one 

 employed by Fitz. 



There are, however, many points about the process 

 which are obscure, and about which I cannot say any- 

 thing at present, but further experiment will, it is hoped, 

 throw light upon the obscurity now enveloping the 

 subject. The above account has been given in the hope 

 that it may prove of some interest to' those engaged 

 in the study of fermentation, and that it may lead to a 

 more extended examination of the action of various 

 species of fungus upon amylaceous substances. 



R. W. Atkinson 



University of Tokio, Japan 



THE ORIGIN AND DISTRIBUTION 

 ORGANIC COLOUR 



OF 



/^OLOUR, throughout the realms of organic nature, is 

 ^-^ a factor hitherto held to be the most capricious in its 

 distribution and the least amenable to any finite law. So 

 uncertain and variable indeed are its manifestations that 

 its claims for the purposes even of specific diagnosis have 

 long since been ignored by the comparative anatomist. 

 Nevertheless, when examined more attentively, an amount 

 of evidence may be adduced sufficient to warrant further 

 inquiry as to whether there is not existent beneath the 

 superficial stratum of apparent disorder, a harmonious 

 imder-current indicative of a derivation in the abstract 

 from one of nature's simplest physical laws, namely, that 

 of polarisation. 



Directing brief attention first to the subject of colour as 

 distributed among the animal world, it will at once be 

 recognised that, with few exceptions, it is only amongst 

 the classes lower in the scale than the mammalia that 

 this element either attains or retains its full exuberance. 

 Even within such limits it will be further found that the 

 beautiful and recently-discovered law of natural selec- 

 tion, for the purposes of concealment or protection, has 

 in many instances so influenced and subordinated all 

 pre-existing characters as to have entirely masked or 

 eliminated them. The lepidopterous order of the class 

 Insecta most prominently illustrates this latter case ; the 

 brilliant and varied hues of many members of this tribe 

 being, as has been ably demonstrated, more especially by 

 Mr. Alfred R. Wallace, in accord either with the flowers 

 they most frequent, the objects upon or adjacent to which 

 they rest in repose, or, still more remarkably, mimetically 

 identical with those of other perfectly distinct species 

 which owe their immunity from the attacks of birds to 

 their peculiar acrid flavour. 



The types among which have been first observed those 

 peculiar colour- characteristics now to be submitted, are 

 more particularly associated with aquatic Hfe, and from 

 these latter it has been found possible to extend and 

 institute comparisons amongst almost every terrestrial 

 group. Reference is here made to the dominance amonsr 



the animal types in question of those so-called " comple- 

 mentary colours " familiar to all acquainted with the 

 working of the polariscope. Of these colours in ques- 

 tion, the combinations red and green, and blue and yellow 

 are the most important, and it is surprising to find how 

 frequently these reproduce themselves in nature. 



Enumerating on this occasion merely a few instances, 

 reference may be first made to those forms in which blue 

 with its complementary hue, yellow, are found associated. 

 Blue, as a rule, enters but to a comparatively trifling ex- 

 tent into the coloration of our indigenous fish fauna, but 

 a remarkable and very gorgeous exception is afforded by 

 the male of the Cuckoo Wrass {Labrus mixtus), which in 

 its adult condition is resplendent with equally-distributed 

 tints of the purest azure and most brilliant orange. These 

 same complementary hues of blue and yellow obtain 

 again in the male of another British fish, known as the 

 Gemmeous Dragonet {jCallionymus lyra). A conspicuous 

 exotic example of the same colour-combination is presented 

 by the Tesselated Parrot Fish of Ceylon {Scarus harice), 

 characterised by its groundwork of azure blue decorated 

 with an hexagonal network of golden yellow. Among the 

 invertebrate division of the animal kingdom, the class of 

 the Crustacea affords several interesting instances of a 

 similar combination. Two of these belonging to the 

 Decapodous order, Galathea stri^osa and Scyllarus 

 arciiis, are of considerable size, having the deep orange 

 hue of the general surface of their carapace variegated 

 with bands and markings of brilliant blue. The Common 

 Lobster {Homarus vulgaris), again, often " sports " into a 

 bright blue variety, variously spotted and mottled with 

 yellow. The legs of the Common Prawn {Pandalus 

 annulicornis) are also most usually decorated with alter- 

 nating rings of blue and orange. The marine copepods, 

 more especially those of tropical seas, abound with 

 instances of the association of these same two com- 

 plementary hues. The class of the MoUusca is one 

 among which blue as a pure colour but very rarely 

 presents itself. There are, however, two Nudibranchs 

 {Goniodoris ccelestis, Desh., and G. elegans, Cantraine) 

 conspicuous for their ground colour of azure, accompanied 

 in each instance by spots or lines of yellow. The last- 

 named and finer of these two species, attaining a length 

 of 2\ inches, and usually classed as a Mediterranean 

 type, was collected by the writer on the rocky shore of 

 the Cies Islands, Vigo Bay, in association with the 

 dredging expedition of Mr. Marshall Hall's yacht NortuXy 

 during the spring of the year 1871. 



Pursuing the investigation among terrestrial types, the 

 bird tribe — although it is necessary here to cite almost 

 entirely tropical forms — produces abundant instances of 

 the association of the same blue and yellow tints. 

 The large Blue and Yellow Macaw {Ara ararauna) 

 of South America forms a most conspicuous illus- 

 tration, and the same two complementary hues will 

 be found coupled together among innumerable other 

 representatives of the parrot tribe, and likewise among 

 the toucans. The most exquisitely beautiful blue bird 

 yet known to science, the Azure Caereba {Ccereba cyanea), 

 is not altogether deficient of the complementary tint 

 of yellow, several feathers of this colour appearing 

 in the wings. One of the Cassowaries {Casuarius kaupi, 

 Sclater), as figured in the Zoological Society's /'r<7<r^(?^/«§'j 

 for the year 1872, is represented as having the skin of 

 the upper and front portion of the throat coloured azure- 

 blue, while immediately behind and adja.cent to this 

 succeeds a patch of bright yellow. A still later and 

 highly characteristic example is likewise afforded by the 

 newly named Euphonia iiisii^nis of Messrs. Sclater and 

 Salvin, figured at PI. lii. Fig. i of the third part of the 

 same Proceedings for this current year. Although our in- 

 digenous avifauna produces very few species in which the 

 colour blue occupies a prominent position, the little Blue 

 Tomtit {Panes cceruleits) is an exception which at the same 



