VIEWS OF ERASMUS DARWIN 228 
the animal originally created, and that these in- 
finitely minute forms are only evolved or distended 
as the embryon increases in the womb. This idea, 
besides being unsupported by any analogy we are 
acquainted with, ascribes a greater tenuity to organ- 
ized matter than we can readily admit” (p. 317); and 
in another place he claims that “we cannot but be 
convinced that the fetus or embryon is formed by 
apposition of new parts, and not by the distention 
of a primordial nest of germs included one within 
another like the cups of a conjurer”’ (p. 235). 
g. To explain instinct he suggests that the young 
simply imitate the acts or example of their parents. 
He says that wild birds choose spring as their building 
time “from the acquired knowledge that the mild 
temperature of the air is more convenient for hatch- 
ing their eggs;’’ and further on, referring to the fact 
that seed-eating animals generally produce their 
young in spring, he suggests that it is “part of the 
traditional knowledge which they learn from the 
example of their parents.” 
10. Hybridity. He refers in a cursory way to the 
changes produced by the mixture of species, as in 
mules. 
Of these ten factors or principles, and other views 
of Dr. Darwin, some are similar to those of Lamarck, 
while others are directly opposed. There are there- 
fore no good grounds for supposing that Lamarck 
was indebted to Darwin for his views. Thus Erasmus 
Darwin supposes that the formation of organs pre- 
cedes their use. As he says, “The lungs must be 
* Zoonomia, vol. i., p. 170. 
