M. V. Fatio on the Coloration of Feathers. 361 
XLII.— On the various Modes of Coloration of Feathers. 
By M. Victor Fario*. 
THE various plumages of birds have been studied in all times, 
and their difference of coloration has been in the present day 
the subject of many interesting works. The question of changes 
of plumage has presented itself in various ways. Is a new 
coloration always the peculiarity of a new feather? or may the 
coloration sometimes undergo alteration in the same tissues ? 
Each of these notions has had its defenders; but the second 
gradually increasing in probability, it has become necessary to 
find out how and by what means these internal modifications 
take place. 
Schlegel}, in 1852, supposed a new life in the feather at the 
approach of sprmg; and most of the naturalists who have paid 
attention to the subject since his time have sought rather to 
throw over this first hypothesis than to substitute for it a new 
and plausible explanation of the phenomenon. 
Nevertheless some theories put forward during the last few 
years have still further subdivided the question. Weinlandt, 
supposing that a pigmented fat came from the body to colour 
the dead feather afresh, did not believe in the presence of what 
may be called a latent colouring principle beneath the apparent 
colour. 
Severtzof § believed in this primitive inherence of the new 
colouring matter, and put forward the ozone of the air as the 
modifying agent of the coloration in general. 
As none of these methods satisfy the mind, and especially as 
none of them can sustain a careful observation, I have taken up 
the question by commencing with the study of the growth and 
anatomy of the feather, which must hereafter facilitate that of 
the ulterior developments. 
I shall not enter here upon the details of these preliminary 
researches, but will confine myself to citing briefly the points 
most indispensable for the comprehension of my subject. I 
shall state, in the first place, that each feather consists of — 
1. A central stalk, or primary axis. 
2. Numerous barbs arranged on the sides of this first stem, 
and forming, as it were, branches or secondary axes. 
3. Numerous barbules regularly implanted upon the barbs, 
and forming tertiary axes. 
* Translated by W. S. Dallas, F.L.S., from the ‘ Bibliothéque Univer- 
selle,’ March 25, 1866, Archives des Sciences, pp- 244-254. 
+ Naumannia, vol. ii. 1. p.2. 
{ Zur Verfarbung der Vogelfeder ohne Mauserung, Cabanis, iv. 1856. 
§ Mikroskopische Untersuchungen iiber die Verfarbung der Federn, &e. 
