in Physics, is that motion by

which bodies convert other bodies related to them, or

at least such as are prepared to be converted, into their

own substance and nature. Thus, flame multiplies it-

self upon oily bodies, and generates new flame; air

upon water, and produces new air; and all the parts,

as well similar as organisable, in vegetables and animals,

first attract with some election or choice, nearly the

same common or not very different juices for aliment,

and afterwards assimilate or convert them to their own

nature.