662 



NATURE 



[May 20, 1922 



our gas factories was closed on certain occasions for 

 days at a time because most of the workers were 

 put out of action, suffering from gas poisoning : 

 there were other similar incidents, and in a number 

 of cases men lost their lives ; which shows that service 

 at home was by no means without its risks. In fact, 

 I might almost say that work in a poison gas factory 

 entailed suffering from gas poisoning sooner or later. 



In research work, Profs. Baker and Thorpe were very 

 prominent throughout the whole period of. the war. 

 They, with other eminent men, gave themselves 

 whole-heartedly to this work, to their own financial 

 disadvantage, and without the prospects of reward 

 which the successful soldier has in view. In science, 

 at any rate, there was no profiteering. A lady of this 

 College, Dr. Whiteley, introduced the use of " S.K." 

 — symbolising South Kensington — a substance that 

 was largely used against the Germans — as well as a 

 new explosive. 



In all the preliminary physiological tests, of course, 

 animals were used ; but volunteers were never 



wanting for the more important experiments in the 

 lethal chamber : and at one time many of the 

 experimental staff at Porton were in a constant state 

 of ill-health owing to the trying nature of this work. 

 One gallant action worthy of record was that of Mr. 

 Barcroft of Cambridge, who, in order to confirm a 

 theory which had an important bearing on our gas 

 tactics, entered the lethal chamber together with a 

 dog, both being entirely unprotected, and remained 

 there while exposed to prussic acid gas until the dog 

 died. 



All honour, then, to the distinguished scientific 

 workers of our nation in general, and of this 

 College in particular, staff and students, who re- 

 sponded to the call of patriotism on the battlefield, 

 in the committee-room, the research laboratory, and 

 the munitions factory ; but, above all, let us hold in 

 grateful remembrance those whose names are in- 

 scribed on this tablet, who not only served their 

 country to the best of their ability, but who gave 

 their lives in doing so. 



The Evolution 



THE paper by Prof. Ewart referred to below con- 

 tains much good and new matter, but the good 

 observations are not exactly recent discoveries, whilst 

 the new conclusions and speculations are rather con- 

 testable, or at least startling. 



The bulk of the paper is very technical, but some 

 of the generalisations concerning the evolution of the 

 coat or coats of feathers of birds never fail to interest 

 a wider circle of readers. The first coat of the young 

 chick is composed of structurally rather simple little 

 feathers, the Neossoptiles or nestling feathers ; the 

 final or finished feathers were called Teleoptiles. The 

 first set is structurally continuous with the next grow- 

 ing set or generation. Then it was found that in the 

 majority of birds not one but two nestling coats were 

 successively developed, both in structural continuity 

 with each other (henceforth distinguished as Proto- 

 and Mesoptiles ; and the latter passing into the 

 Teleoptiles). 



These several sets or generations vary much in 

 relative importance, time of their emergence or growth, 

 size and temporary functions, in the different groups 

 of birds. For example, whilst the first set forms the 

 duckUng's first and effective jacket, it is the second 

 set which in the penguins makes a very woolly and 

 warm coat which lasts the youngsters many months, 

 until these fluffy down-like feathers are supplemented 

 by typical adult feathers. Moreover, in the duckling 

 this second set is in the interesting condition of re- 

 duction, being practically crowded out of existence 

 between the first and the third set. It depends upon 

 the group of birds whether and how and to what extent 

 these Mesoptiles become vestigial. 



Again, while in ducks and penguins^ in fact, in 

 the overwhelming majority of birds — the difference 

 between their nestling coat and the final dress is 

 enormous (let us remember the callow blind-bom 

 nestling of a thrush, with a few large wavy tufts, 

 before the final feathers begin to sprout), in the casso- 

 waries and emus the differences between the successive 

 coats are reduced to a question of mere size. In 

 short, the variations are almost endless and still 

 promise many new discoveries, all the more interest- 

 ing when correctly correlated with the bird's ecology. 

 Indeed, here is a wide and fertile field for fascinating 

 speculation. Let us see how Prof. Ewart has tackled 

 the matter. The chapters dealing with a more general 



' "Nestling Feathers of the Mallard," by Prof. J. Ccssar Ewart, Pro- 

 ceedings, Zoological Society of London, 1921,'^p. 609. 



of Plumage.^ 



account of the evolution of the plumage are an in- 

 stance of that kind of " Natur- Philosophic " which, 

 entranced by the new Darwinism, did not allow itself 

 to be hampered by facts nor to be checked by the 

 perhaps equally sanguine speculations of others. 



Although the earliest birds known are the two 

 specimens of Archaeopteryx from the upper Jurassic, 

 our author states that at the beginning of the Jurassic 

 age the coat of birds may have consisted only of 

 Protoptiles ; and the scene of the dawn of feathers of 

 such low order is set in a land with desert climate, 

 cold and dry, atmospheric conditions which would 

 engender feathers. The dryness would cause the 

 hypothetical feather "filaments" or cryptoptiles to 

 split or fray into a kind of brush, and ' ' whatever bird 

 or beast became warm-blooded would appreciate an 

 overcoat. ' ' Presumably the creature became heated by 

 its attempts to flutter, and the increased temperature 

 made it liable to catch cold and call for a feather coat. 

 Thus a teleological unscientific notion is preferred to 

 the suggestion that a gradually improving coat (and 

 frayed brush-like scales would be less heat-conductive 

 than ordinary reptilian scales) might induce first 

 stable and then permanently increased blood-tem- 

 perature. Surely the important feature would be 

 the thermostatic result, resulting incidentally from 

 the development of a better non-conducting coating. 



In any case this first set of little Protoptiles formed 

 at best a poor sort of flimsy overcoat. When, how- 

 ever, the climate changed from cold and dry to cold 

 and damp, "during perhaps a cold phase of a glacial 

 epoch," the coat was changed into the Mesoptile coat 

 by the lengthening of the previously existing branches, 

 or barbs, of the brush, and by the sprouting of new 

 additional barbs. At any rate thus was evolved the 

 thick, fluffy, warm coat of the young penguins, and 

 it "is probably as useful now to the penguin chicks 

 hatched within or near the Antarctic circle as it was 

 when originally acquired during perhaps a cold stage 

 of a glacial epoch." 



Later, as the climate improved [interglacial] this 

 fur-Hke second coat was in most other birds more or 

 less suppressed [perhaps it proved too hot] and a third 

 coat was constructed out of what gradually improved 

 into feathers proper, which in turn were differentiated 

 into downs and contour feathers, and some of these 

 became, through use, etc., specialised into remiges 

 and rectrices. At last there was a chance for a flying 

 bird. Ostriches and similar birds perhaps never did 



NO. 2742, VOL. 109] 



