934 The Zoologist— October, 1867. 



Mr. Tegetmeier is, I think, fairly established, but what is that nutri* 

 ment ? Is it anything distinct from the food of the parent softened 

 and prepared by a digestive process of the parent's stomach ? The 

 more thought I give to this interesting question, the more decidedly 

 does this appear the natural and truthful solution : and here it is right 

 ■ — nay, it is absolutely necessary — to add that the truly great, and 

 generally philosophic, Hunter, evinces a confusion of ideas on this 

 interesting question exactly parallel to that exhibited by Mr. Teget- 

 meier in the paragraphs I have cited. After referring to the power 

 possessed by Bucklers of supplying immediately from their own bodies 

 the nourishment proper for their offspring, Hunter goes on to say that 

 "all birds of the dove hind are endowed with a similar power." This 

 he evidently considers the equivalent of milk, and he thus describes 

 its production : — " During incubation the coats of the crop in the 

 pigeon are gradually enlarged and thickened, like what happens to the 

 udder of females in the class Mammalia in the term of gestation. On 

 comparing the state of the crop, when the bird is not silting, with its 

 appearance during incubation, the difference is very remarkable. In 

 the hist case, it is thin and membranous ; but by the lime the young 

 are about to be hatched, the whole, except what lies in the trachea, 

 becomes thicker, and takes on a glandular appearance, having its 

 internal surface very irregular. It it likewise evidently more vascular 

 than in its former state, that it may convey a quantity of blood suffi- 

 cient for the secretion of the substance which is to nourish the young 

 for some days after they are hatched." 



From this passage we are certainly led to infer that the "coats of 

 the crop" secrete from the blood the substance which is to nourish 

 the young; but Hunter goes on to say, "Besides the dove kind, 

 I have some reason to suppose parrots to be endowed with the same 

 faculty, as they have the power of throwing out the contents of the 

 crop and feeding one another. 1 have seen the cock parroquet 

 regularly feed the hen, by first filling his own crop and then supplying 

 her from his beak : parrots, macaws, cockatoos, &c, may likewise be 

 observed to have the action of throwing up the food, and often do it." 

 Surely this conveys no idea of secreting food from the blood : if 

 doves and parrots are " endowed with the sa?ne faculty," and if that 

 faculty is " filling their own crops," " throwing up the food," and with 

 this " thrown-up food " " feeding one another," we have a very different 

 phenomenon to the lactation of Mammalia. 



Mr. Tegetmeier has some very sensible observations on the fitness 



