572 THE AMERICAN NATURALIST. [Vou. XXXII. 
Agriculture” as representing in one volume the standards by 
which the economic value of most of the mammals, birds, 
insects, and reptiles coming under the special notice of the 
Department have been estimated. It may be added that all 
subsequent publications of the Department indicate that there 
has been little change in these standards since the issue of the 
above-mentioned work of Dr. A. K. Fisher. Published in 1893, 
this well-prepared and finely illustrated little book represents 
the highest attainment in the development of economic orni- 
thology yet reached in this country or abroad. Dr. C. Hart 
Merriam, under whose supervision the work was carried on, in 
his letter of transmittal to the Secretary of Agriculture, states 
that only two of the seventy-three species and races of rapacious 
birds found in the United States “ need be taken into account 
as enemies to agriculture.” 
Before the investigations which resulted in this verdict were 
begun, it was the general belief, even among many observing 
and fair-minded people, that only two or three of the whole num- 
ber were of any possible use to man. A study of the tabulated 
lists of stomach contents shows that this reversal of opinion 
rests solely on two factors. One of these is the relative amount 
of certain food-stuffs taken by the different species ; the other 
is the character of the animal food preyed upon, whether formed 
of species noxious or beneficial to man from the agricultural 
standpoint. 
Granting that the determinations of the first class were 
accurately made (and there is no reason whatever to doubt 
them), we may well inquire, By what standard do the zodlogists 
of the Department of Agriculture decide that certain species 
of mammals, birds, or insects, are considered to be noxious or 
otherwise? Nowhere in this work are the two classes defined, 
nor are any reasons given for the evident distinctions drawn 
between noxious and beneficial species enumerated in the 
food lists. The novice in such matters naturally seeks to know 
on what basis the doctors have decided for or against a hawk 
or an owl, but he is not informed, except as he can glean an 
item here and there among the biographies of the various 
species. This study reveals the following standards: (1) cat 
