INTRODUCTION. 
xv 
diately above the gizzard; which, as we have just described, is more mem- 
branous than muscular, in the carnivorous and piscivorous kinds ; as the 
nature of their food requires but little attrition to comminute it, and as it 
is easier of digestion than that of those which live on grain ; the latter 
bearing some analogy to herbivorous quadrupedes, while the former may, 
in this respect, be compared with other flesh-devouring animals, and even 
with man himself. Besides this expansion of the gullet, near the gizzard, 
which, in some few birds, as the Cuckoo,'“ the Goatsucker, and the 
Bullfinch, nearly approaches the form of a stomach. Nature has bestowed 
on many of the species, as we have before-remarked, an expansive sack, 
or reservoir, just below the entrance of the oesophagus, called the inglu- 
vies, crop, or craw, in which the food is slightly macerated, and pre- 
pared for the more easy digestion in the stomach.' ‘ This sack also serves, 
in some kinds, as a storehouse for the food of their young, from which the 
contents are ejected by the parents of the pigeon tribe, and given to their 
progeny. To render the food more nutritious, the Dove secretes in the 
spring, a white, serous liquor, resembling milk, from minute vessels, 
situated about the crop. The diversified means which Nature has adopted 
to answer the same ends, exhibit a boundless store. The Heron, the 
Shag, the Corvorant, the Rook, and many others, to which she has 
denied a crop like that of the Pigeon, she has given an elastic skin or 
This organ, in the birds just mentioned, is exceedingly large. In the Land Rail, it is of 
an intermediate size ; and, in the Tit Lark, it can scarcely be discerned. Its coats are thicker 
than the rest of the tube, and appear wrinkled, in a slight degree resembling the stomach. 
" The crop is lined with small glands, which separate a viscid liquor on its internal surface. 
This assists the maceration of the food, and gallinaceous birds are sometimes suffocated, by the 
pulse and grain which they swallow expanding to a great size. In the year 1805, some mouldy 
chocolate, softened by water, was given to the fowls in my court ; three of them died ; one of 
which was a fine strong cock, called, by the children, “ the old lord.” Within twenty minutes 
after filling its crop with this food, of which all the fowls were greedily fond, it suddenly 
screamed loudly, leapt up, and instantly expired. 
