164 STUDY OF NATURAL HISTORY. 
other. Great revolutions in science are scarcely ever 
effected but after their authors, and the generation 
to which they belonged, have ceased to breathe. 
Yet there is nothing unnatural or unaccountable 
in the slowness of this removal of error. After 
all, the authority of names, in questions of pure 
science, is not what it used to be. It may, indeed, 
for a time, operate against the diffusion of truth ; but 
truth, once discovered, stands in no need of such 
aid. During the age when the zoological world 
bowed with unhesitating submission to the opinions 
of the great naturalist of Sweden, it was affirmed 
by him, and believed by the world, that corals were 
plants, and that swallows passed the winter under 
the ice.* Such prejudices are now only to be 
laughed at: but we may fairly enquire whether 
many of the opinions we now hold, will not equally 
excite a smile from our successors. 

* The celebrated Peter Collinson thus writes to Linnzus, 
when opposing this latter prejudice :—-‘* Your reputation is so 
high in the opinion of the learned and curious of this age 
(1762), that what you assert is taken and allowed to be a real 
fact; for when I have been reasoning on the improbability of 
swallows living under water, it has been replied, Dr. Linneus 
says so, and will you dispute his authority.” — Lin. Cor. vol. i. 
p- 54, 55. 
