calves lick themselves and swallow many of their hairs before their nativity:  which however puppies do not, (Swammerden, p. 319.  Flemyng Phil.  Trans.  Ann. 1755. 42).  And towards the end of gestation, the foetus of all animals are proved to drink part of the liquid in which they swim, (Haller.  Physiol.  T. 8. 204).  The white of egg is found in the mouth and gizzard of the chick, and is nearly or quite consumed before it is hatched, (Harvie de Generat. 58).  And the liquor amnii is found in the mouth and stomach of the human foetus, and of calves; and how else should that excrement be produced in the intestines of all animals, which is voided in great quantity soon after their birth; (Gipson, Med.  Essays, Edinb.  V. i. 13.  Halleri Physiolog.  T. 3. p. 318. and T. 8).  In the stomach of a calf the quantity of this liquid amounted to about three pints, and the hairs amongst it were of the same colour with those on its skin, (Blasii Anat.  Animal, p.m. 122).  These facts are attested by many other writers of credit, besides those above mentioned.

III.  It has been deemed a surprising instance of instinct, that calves and chickens should be able to walk by a few efforts almost immediately after their nativity:  whilst the human infant in those countries where he is not incumbered with clothes, as in India, is five or six months, and in our climate almost a twelvemonth, before he can safely stand upon his feet.

The struggles of all animals in the womb must resemble their mode of swimming, as by this kind of motion they can best change their attitude in water.  But the swimming of the calf and chicken resembles their manner of walking, which they have thus in part acquired before their nativity, and hence accomplish it afterwards with very few efforts, whilst the swimming of the human creature resembles that of the frog, and totally differs from his mode of walking.

There is another circumstance to be attended to in this affair, that not only the growth of those peculiar parts of animals, which are first wanted to secure their subsistence, are in general furthest advanced before their nativity:  but some animals come into the world more completely formed throughout their whole system than others:  and are thence much forwarder in all their habits of motion.  Thus the colt, and the lamb, are much more perfect animals than the blind puppy, and the naked rabbit; and the chick of the pheasant, and the partridge, has more perfect plumage, and more perfect eyes, as well as greater aptitude to locomotion, than the callow nestlings of the dove, and of the wren.  The parents of the former only find it necessary to shew them their food, and to teach them to take it up; whilst those of the latter are obliged for many days to obtrude it into their gaping mouths.