Ornithology. 47 
more rapidly at the present time than at any period since history 
began. 
The great aim of ornithologists from the dawn of our science 
down to the present hour has been to find a key to a natural 
system—in other words, to comprehend the divine idea of a 
definite plan which can be expressed in the formulas of science. 
For a long time, the characteristics of the bill and feet of 
birds constituted the basis of their classification. Since about 
1820 to 1825 Continental European writers have generally 
adopted the vocal muscles, the song, number and length of the 
quills, scales and feathers of the legs, the number of tail feathers, 
webbing of the feet, position of the hind toe, and the treatment 
of their young, as elements for classification. 
As far back as the middle of the sixteenth century, they were 
classified by their habits, and the locations wherein found. 
There were instituted four divisions of the birds of prey—wad¬ 
ers, swimmers, and those nesting on trees, and those which nest 
on the ground. To this was next added, the nature of their 
food. About a century later, the first attempt at a treatise on 
classification was published, which divided the land birds into 
two groups—those with curved bills and claws, and those with 
straight. The water birds were also divided into two such 
groups—the waders and the swimmers. Another work followed, 
early in the eighteenth century, making some improvements 
on the first, and the two became the basis of Linneus’ classifi¬ 
cation half a century later. 
This great naturalist gave us six orders, thus: Accipitres, 
Picse, Passeres; Gallinae, Anseres and Grallae. In 1770, Bris- 
son, another eminent naturalist, made twenty-six orders, and 
one-hundred and fifteen genera, based upon the bill, toes and 
their connecting membranes, and the feathers of the legs. 
Fourteen years later, Schaeffer published his Elementa Ornith- 
ologica, in which he divided birds according to the feet, into 
two families—the nudipedes, and plumipedes—as Brisson had 
previously divided them into the fissipedes, and palmipedes. 
Following him shortly afterwards Scopoli gave us retipedes, 
and scutipedes. Latham, who wrote in the latter part of the 
eighteenth and first part of the present century, constructed 
