The Zoologist — October, 18G7. 933 



longer on the sterile eggs. The production of the soft food, however, 

 may be hastened a day or two. 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 con- 

 vulsive shudder, is received into the lower mandible or jaw which is 

 widely expanded to receive it. It is singular that so simple an action 

 as this should have been 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 grains and seeds only, until such time as they are 

 able to fly and seek their own nourishment." — p. 10. 



I confess to a craving for more information than these passages 

 convey: my readers will observe that the "pigeon's milk" is dis- 

 tinctly spoken of as a " secretion," that it is " produced in the crops 

 of the parents," and that as the young advance it "lessens in quan- 

 tity." Now what is this "pigeon's milk" ? the term is "as old as the 

 hills," but the interpretation is still lacking : a secretion is distinctly 

 understood as a fluid (or perhaps solid) evolved from that which 

 secretes ; thus the milk of sucklers is with great propriety called a 

 " secretion " from the blood, and there are other animal secretions 

 equally familiar, but is pigeon's milk a secretion from the blood ? and 

 if so how can it be secreted in the crop, which is the receptacle of food ? 

 As I understand secretion, it cannot be applied to macerated food. 

 That young pigeons receive nutriment in the manner described by 



