324 General Notes. [ April, 
_ abling them to escape scarcity in one region which might other- 
wise decimate them, by simply passing to a more favorable region 
where they can find food. It does not follow, however, from 
these facts that the indefinite multiplication of either birds or 
insects is beneficial, since there is a limit beyond which such mul- 
tiplication becomes harmful. 
We recommend and heartily endorse the following concluding 
passages from the paper 
“We are therefore sure that the destruction of any species of 
insectivorous bird or predaceous insect is a thing to be done, if 
at all, only after the fullest acquaintance with the facts. The 
natural presumptions are nearly all in their favor. It is also cer- 
tain that the species best worth preserving are the mixed feeders 
and not those of narrowly restricted dietary (parasites, for instance) 
—that while the destruction of the latter would cause injurious 
oscillations in the species affected by them, they afford a very un- 
certain safeguard against the vise of such oscillations. In fact, 
their undue increase would be finally as dangerous as their dimi- 
nution. lt Sg 
“ When we compare the results of the primitive natural order 
with the interests of man, we see that, with much coincidence, 
there is also considerable conflict. While the natural order is 
directed to the mere maintenance of the species, the necessities of 
man usually require much more. They require that the plant 
or animal should be urged to excessive and superfluous growth and 
increase, and that all the surplus, variously and widely distributed 
in nature, should now be appropriated to the supply of human 
wants. From the consequent human interferences with the estab- 
lished system of things, numerous disturbances arise, many © 
them full of danger, others fruitful of positive evil. Oscillations of 
species appear, not less injurious to man than to the plants and 
animals more directly involved. Indeed, most of the serious 10- 
sect injuries, for example, are due to species whose injurious oscil- 
lations have resulted from changes of the organic balance initiated 
by man. | 
“To avoid or mitigate the evils likely to arise, and to adapt 
the life of his region more exactly to his purposes, man ‘must 
study the natural order as a whole, and must understand the dis- 
turbances to which it has been subject. Especially, he must know 
the forces which tend to the reduction of these disturbances, and 
those which tend to perpetuate or aggravate them, in order that 
he may reinforce the first, and weaken or divest the second. _ 
“The main lesson of conduct taught us by these facts an¢ 
reasonings, is that of conservative action and exhaustive inquiry- 
Reasoning unwarranted by facts, not correctly and sufficiently 
reasoned out, are equally worthless and dangerous for practical 
use.” 
Baron de. Chaudoir, of Russia, R. H. McLachlan, of England, 
and Baron C. R. Osten Sacken, formerly Russian Consul General 
