Page:The Works of William Harvey (part 1 of 2).djvu/296

 19G ON GENERATION.

are wont, after having bruised an herb or a fruit, to squeeze out the juice or pulp) the softer or more liquid part is forced out, comes to the top, and is transferred to the commencement of the intestinal canal ; which in birds takes its rise from the upper part of the stomach near the entrance of the oesophagus. That this is the case in many genera of birds is obvious ; for the stones and other hard and rough substances which they have swallowed, if long retained, become so smooth and polished that they are unfit to comminute tlje food, when they are discharged. Hence birds, when they select stones, try them with their tongue, and, unless they find them rough, reject them. In the stomach of both the ostrich and cassowary I found pieces of iron and silver, and stones much worn down and almost reduced to nothing ; and this is the reason why the vulgar believe that these creatures digest iron and are nourished by it.

If you apply the body of a hawk or an eagle, or other bird of prey, whilst fasting, to your ear, you will hear a distinct noise, occasioned by the rubbing, one against another, of the stones contained in the stomach. For hawks do not swallow pebbles with a view to cool their stomachs, as falconers commonly but erroneously believe, but that the stones may serve for the com- minution of their food; precisely as other birds, which have mus- cular stomachs, swallow pebbles, sand, or something else of the same nature, to crush and grind the seeds upon which they live.

The stomach of birds, then, is situated within the cavity of the abdomen, below the heart, lungs and liver : the crop, how- ever, is without the body in some sort, being situated at the lower part of the neck, over the os jugale or merry-thought. In this bag, as I have said, the food is only macerated and softened; and several birds regurgitate and give it to their young, in some measure as quadrupeds feed their progeny with milk from their breasts ; this occurs in the whole family of the pigeons, and also among rooks. Bees, too, when they have returned to their hives, disgorge the honey which they have collected from the flowers and concocted in their stomachs, and store it in their waxen cells ; and so also do hornets and wasps feed their young. The bitch has likewise been seen to vomit the food which she had eaten some time before, in a half-digested state, and give it to her whelps : it is not, therefore, to be greatly