136 
A SCIENTIFIC APPRECIATION [oh. vi. 
this last conclusion, but it is no disparagement 
of its author to say, that in this passage, as well as 
in others that might be quoted, he was greater as 
anatomist than as a logician. 
“He was indeed thoroughly grounded in 
anatomy, and though undoubtedly the digestive 
organs of birds have a claim to the fullest con¬ 
sideration, yet MacGillivray himself subsequently 
became aware of the fact that there were several 
other parts of their structure as important from the 
point of view of classification. He it was, 
apparently, who first detected the essential 
difference of the organs of voice presented by some 
of the New World Passeres (subsequently known 
as Clamatores ); and the earliest intimation of this 
seems to be given in his anatomical description of 
the Arkansas Flycatcher, Tyr annus verticalis, 
which was published in 1838 ( Ornithol . Biog. iv., p. 
425), though it must be admitted that he did not— 
because he then could not—perceive the bearing 
of their difference, which was reserved to be shown 
by the investigation of a still greater anatomist, 
and of one who had fuller facilities for research, 
and thereby almost revolutionised, as will presently 
be mentioned, the views of systematists as to this 
Order of Birds. . . 
“His scheme of classification, being as before 
stated partial, need not be given in detail. Its 
great merit is that it proved the necessity of 
combining another and hitherto much-neglected 
factor in any natural arrangement, though vitiated, 
as so many other schemes have been, by being 
based wholly on one class of characters.’ 7 
In an appreciation there is always a danger of 
overpraising the subject, and it is therefore satis¬ 
factory to be able to quote the verdict of the 
