INTRODUCTION 63 



examples of it are comparatively scarce. Moreover, he stated subsequently 

 that he thereby hoped to excite other naturalists to share with him the 

 investigations he was making on a subject which had hitherto escaped 

 notice or had been wholly neglected, since he considered that he had 

 proved the disposition of the feathered tracts in the plumage of Birds to 

 be the means of furnishing characters for the discrimination of the various 

 natural groups as significant and important as they were new and un- 

 expected.^ There was no need for us here to quote this essay in its 

 chronological place, since it dealt only with the generalities of the subject, 

 and did not enter upon any systematic details. These the author reserved 

 for a second treatise which he was destined never to complete. He kept 

 on diligently collecting materials, and as he did so was constrained to 

 modify some of the statements he had published. He consequently fell 

 into a state of doubt, and before he could make up his mind on some 

 questions which he deemed important he was overtaken by death.^ Then 

 his papers were handed over to his friend and successor, Burmeister, 

 afterwards and for many years of Buenos Aires, who, with much skill 

 elaborated from them the excellent work known as Nitzsch's Ptenjlographie, 

 which was published at Halle in 1840. There can be no doubt that the 

 editor's duty was discharged with the most conscientious scrupulosity ; 

 but, from what has been just said, it is certain that there were important 

 points on which Nitzsch was as yet undecided — some of them perhaps of 

 which no trace appeared in his manuscripts, and therefore as in every 

 case of works posthumously published, unless (as rarely happens) they 

 have received their author's '■^imprimatur" they cannot be implicitly 

 trusted as the expression of his final views. It would consequently be 

 unsafe to ascribe positively all that appears in this volume to the result of 

 Nitzsch's mature consideration. Moreover, as Burmeister states in his 

 preface, Nitzsch by no means regarded the natural sequence of groups 



^ It is still a prevalent belief that feathers grow almost uniformly over the whole 

 surface of a Bird's body ; some indeed are longer and some are shorter, but that is 

 about all the difference perceptible to most people. It is the easiest thing for any- 

 body to satisfy himself that this, except in a few cases, is altogether an erroneous 

 supposition (see Ptertlosis). Before Nitzsch's time the only men who seem to have 

 noticed this fact were the great John Hunter and the accurate Macartney. But the 

 observations of the former on the subject were not given to the world until 1836, 

 when Owen introduced them into his Catcdogtte of the Museum of the College of 

 Surgeons in London (vol. iii. pt. ii. p. 311), and therein is no indication of the fact 

 having a taxonomical bearing. The same may be said of Macartney's remarks, which, 

 though subsequent in point of time, were published earlier, namely, in 1819 (Rees's 

 Cyclopiedia, xiv. art. ' Feathers '). Ignorance of this simple fact has led astray 

 many celebrated painters, among them Landseer, whose pictures of Birds nearly always 

 shew an unnatural representation of the plumage that at once betrays itself to the 

 trained eye, though of course it is not perceived by spectators generally, who regard 

 only the correctness of attitude and force of expression, which in that artist's work 

 commonly leave little to be desired. Every draughtsman of Birds to be successful 

 should study as did Mr. Wolf, the plan on which their feathers are disposed. 



"^ Though not relating exactly to our present theme, it woiild be improper to 

 dismiss Nitzsch's name without reference to his extraordinary labours in investigating 

 the insect and other external parasites of Birds, a subject which as regards British 

 species was subsequently elaborated by Denny in his Monograpliia Anoplurorum 

 Britanniw (1842) and in his list of the specimens of British ^l/iOjoZwra in the collection 

 of the British Museum. 



