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 If a pair of chipped or hatching eggs are put under a pair of birds that have been sitting for sixteen days, their presence will always stimulate the secretion of the soft food, and the young will be duly nourished. The formation of this curdy secretion—true pigeon's milk—is a very remarkable fact; it seems determined altogether by the process of sitting; it is produced equally in both parents, though the hen sits for about twenty hours, and the cock usually for only four—namely, from about ten or eleven in the morning to two or three in the afternoon.

To receive this nourishment the young thrusts its beak into the side of the mouth of the old bird, in such a position that the soft food which is disgorged from the crop of the parent, with a sort of convulsive shudder, is received into the lower mandible or jaw, which is widely expanded in order to receive it. It is singular that so simple an action as this should have heen so greatly misrepresented as it has been by many writers. Even so good an observer as Yarrell described, in his "British Birds," the old pigeons as feeding the young by placing their beaks in the mouths of the little ones, and overlooked altogether the beautiful adaptation of the broad spoon-shaped lower jaw to the habits of the animals.

As the young advance, the soft food lessens in quantity, and the grain and seeds that constitute the nourishment of the parents become mingled with it; and when about eight or ten days old the young are fed with disgorged grain and seeds only, until such time as they are able to fly and seek their own nourishment.

The secretion of this curdy nutriment was first described in the "Philosophical Transactions" by the celebrated physiologist John Hunter, whose account of the process is as follows:—

"There is infinite variety in the means by which nature provides for the support of the young. In many insects it is effected by the female instinctively depositing the egg, or whatever contains the rudiments of the animal, in such a situation that, when hatched, it may be within reach of proper food; others, as the humble bee, collect a quantity of peculiar substances which serves both as a nidus for the egg and nourishment for the maggot, when the embryo arrives at that state. Most birds, and many of the bee tribe, collect food for their young. There is likewise a number of animals capable of supplying immediately from their own bodies the nourishment proper for their offspring during this stage, a mode of nourishment which has hitherto been supposed to be peculiar to that class of animals which Linnæus calls Mammalia; nor has it, I imagine, been ever suspected to belang to any other.

"I have, however, in many inquiries concerning the various modes in which young animals are nourished, discovered that all the Dove kind are endowed with similar power. The young pigeon, like the young quadruped, till it is capable of digesting the common food of its kind, is fed with a substance suited for that purpose by the parent animal; not, as the Mammalia, by the female alone, but also by the male, which, perhaps, furnishes this nutriment in a degree still more abundant. It is a common property of birds, that both male and female are