Most, if not all, of your readers have heard of the newly-invented
machine for hatching and rearing in chickens, without the maternal aid
of the hen; probably many of them have paid a visit (and a _shilling_)
at No. 4. Leicester Square, where the incubator is to be seen in full
operation. The following extract will, therefore, be acceptable, as it
tends to show the truth of the inspired writer's words, "There is no new
thing under the sun:"--
"Therefore ... it were well we made our remarks in some
creatures, that might be continually in our power, to observe in
them the course of nature, every day and hour. Sir _John
Heydon_, the Lieutenant of his Majesties Ordnance (that generous
and knowing gentleman and consummate souldier, both in theory
and practice) was the first that instructed me how to do this,
by means of a furnace, so made as to imitate the warmth of a
sitting hen. In which you may lay several eggs to hatch and by
breaking them at several ages, you may distinctly observe every
hourly mutation in them, if you please. The first will be, that
on one side you shall find a great resplendent clearness in the
white. After a while, a little spot of red matter, like blood
will appear in the midst of that clearness, fast'ned to the
yolk, which will have a motion of opening and shutting, so as
sometimes you will see it, and straight again it will vanish
from your sight, and indeed, at first it is so little that you
cannot see it, but by the motion of it; for at every pulse, as
it opens you may see it, and immediately again it shuts, in such
sort as it is not to be discerned. From this red speck, after a
while, there will stream out a number of little (almost
imperceptible) red veins. At the end of some of which, in time,
there will be gathered together a knot of matter, which by
little and little will take the form of a head and you will, ere
long, begin to discern eyes and a beak in it. All this while the
first red spot of blood grows bigger and solider, till at length
it becomes {85} a fleshy substance, and, by its figure, may easily
be discern'd to be the heart; which as yet hath no other inclosure
but the substance of the egg. But by little and little, the rest
of the body of an animal is framed out of those red veins which
stream out all about from the heart. And in process of time,
that body encloses the heart within it by the chest, which grows
over on both sides, and in the end meets and closes itself fast
together. After which this little creature soon fills the shell,
by converting into several parts of itself all the substance of
the egg; and then growing weary of so strait a habitation, it
breaks prison and comes out a perfectly formed chicken."--Sir
Kenelm Digby's _Treatise of Bodies_, Ch. xxiv. p. 274. ed. 1669.
Could Sir Kenelm return to the scenes of this upper world, and pay a
visit to Mr. Cantelo's machine, his shade might say with truthfulness,
what Horace Smith's mummy answered to his questioner,--
"--We men of yore
Were versed in all the knowledge you can mention."
The operations of the two machines appear to be precisely the same: the
only difference being the Sir Kenelm's was an experimental one, made for
the purpose of investigating the process of nature; while Cantelo's, in
accordance with "the spirit of the iron time," is a practical one, made
for the purposes of utility and profit. Sir Kenelm's Treatise appears to
have been first published in the year 1644.