INTRODUCTION. 
19 
characters of objects are useful and interesting. To such 
persons a manual, lik^ the present, containing a very con- 
densed history of the species, is of importance, as it en- 
ables them readily to discover the name of any particular 
bird, and consequently to refer to any more extended work 
for further information, should they desire it. Persons 
having studied birds at intervals, as opportunities have 
occurred, and having thus acquired considerable, though 
disjointed, information, will also find it beneficial to refer 
frequently to a general systematic catalogue, including the 
essential characters of the species, genera, and families. 
Students or collectors, making excursions to distant places, 
and not finding it convenient to carry large treatises with 
them, will also be benefited by such a catalogue. In short, 
the uses of manuals like the present are numerous, and so 
obvious, that it is unnecessary to say more regarding them. 
Only, let the student not be satisfied with the little which 
they contain, but use them as a means of acquiring more 
knowledge, and of connecting and systematizing what he has 
already obtained. 
In all sciences and arts, peculiar terms must be employed, 
and parts must be intelligibly defined. For the use of per- 
sons commencing the study, or not very proficient in it, I 
shall here present such explanations as will enable them to 
apply the characteristic phrases employed to the objects 
which they describe. 
Birds are warm-blooded, oviparous, vertebrate animals. 
They have a brain, enclosed within a skull, a spinal marrow, 
protected by vertebrse, nerves issuing from these central 
parts, and distributed to all the organs. Their heart is 
double, one side of it receiving the blood from the veins, 
and sending it out by the pulmonary artery into the lungs, 
whence, on being subjected to the influence of the air, it re- 
turns by the pulmonary veins to the other side of the heart, 
which transmits it, by the aorta, to aU parts of the body. 
