PRESERVATION OF ANIMALS. 109 
Some species of birds, such as starlings, jackdaws, rooks, jays, 
and speckled magpies, are distinguished for destroying maybugs 
or cockchafers. A movement in the same direction has recently 
taken place in our own country, in regard to the preservation and 
propagation of salmon. For the former, the Salmon Fisheries 
Act has been passed, and towards the latter, breeding ponds have 
been successfully established upon the river Tay, in Scotland. 
Darwin, in his Origin of Species, when speaking of the won- 
derful dependence of animals and plants upon each other says, 
‘“‘in Staffordshire, on the estate of a relation, where I had ample 
means of investigation, there was a large and extremely barren 
heath, which had never been touched by the hand of man; but 
several hundred acres of exactly the same nature had been enclosed 
twenty-five years previously and planted with Scotch fir. The 
change in the native vegetation of the planted part of the heath 
was most remarkable, more than is generally seen in passing 
from one quite different soil to another; not only the proportional 
numbers of the heath plants were wholly changed, but twelve 
species of plants (not counting grasses and carices), flourished in 
the plantations, which could not be found on the heath. The 
effect on the insects must have been still greater, for six insecti- 
vorous birds were common in the plantations, which were not to 
be seen on the heath; and the heath was frequented by two or 
three distinct insectivorous birds. 
Another extract, I cannot forbear making, ‘ From experiments 
which I have lately tried, I have found that the visits of bees 
are necessary for the fertilisation of some kinds of clover (Zrifo- 
lium pratense), as other bees cannot reach the nectar. Hence I 
have very little doubt, that if the whole genus of humble bees 
become extinct or very rare in England, the heartsease and red 
clover would become very rare or wholly disappear. The number 
of humble bees in any district depends in a great degree on the 
number of field mice, which destroy their combs and nests. Now 
the number of mice is largely dependent, as every one knows, on 
the number of cats, hence it is quite credible that the presence of a 
feline animal in large numbers in a district might determine, 
‘through the intervention first of mice and then of bees, the fre- 
quency of certain flowers in that district.” 
