202 LAMARCK, HIS LIFE AND WORK 
tables seem consequent to the other properties of the 
materials which possess them” (Zhe Loves of the 
Plants, p. 38, note). 
In his Zoonomta (§ xxxix., vi.) Darwin also speaks 
of the efficient cause of the various colors of the 
eggs of birds and of the hair and feathers of animals 
which are adapted to the purpose of concealment. 
“Thus the snake, and wild cat, and leopard are so 
colored as to resemble dark leaves and their light in- 
terstices’’ (p. 248). The eggs of hedge-birds are 
ereenish, with dark spots; those of crows and mag- 
pies, which are seen from beneath through wicker 
nests, are white, with dark spots; and those of larks 
and partridges are russet or brown, like their nests or 
Situations., ‘re “adds: “' The: final? cause of itheis 
colors is easily understood, as they serve some pur- 
pose of the animal, but the efficient cause would seem 
almost beyond conjecture.” Of all this subject of 
protective mimicry thus sketched out by the older 
Darwin, we find no hint or trace in any of Lamarck’s 
writings. 
8. Great length of time. He speaks of the “ great 
length of time since the earth began to exist, per- 
haps millions of ages before the commencement of 
the history of mankind ” (p. 240). 
In this connection it may be observed that Dr. 
Darwin emphatically opposes the preformation views 
of Haller and Bonnet in these words: 
“Many ingenious philosophers have found so great 
difficulty in conceiving the manner of the reproduc- 
tion of animals that they have supposed all the 
numerous progeny to have existed in miniature in 
