Aristotle : On the parts of animals / translated, with introduction and notes by W. Ogle.
- Aristotle
- Date:
- 1882
Licence: Public Domain Mark
Credit: Aristotle : On the parts of animals / translated, with introduction and notes by W. Ogle. Source: Wellcome Collection.
180/316 page 132
![character acts as a protection to the breast, which owing to its form would be very weak, were it not amply covered. Below the breast lies the belly, extending, as in quadrupeds and in man, to the vent and to the place where the legs are jointed to the trunk. Such, then, are the parts which lie between the wings and the legs. Birds like all other animals, whether produced viviparously or from eggs, have an umbilical cord during their development, but, when the bird has attained to fuller growth, no signs of this remain visible. The explanation of this will be set forth in the treatise on Generation and Development, but amounts to this, that in birds the umbilical cord unites with the intestine, and is not a portion of the vascular system, as is the case in the vivipara.*^ Some birds, again, are well adapted for flight, their wings being large and strong. Such, for instance, are those that have talons and live on flesh. For their mode of life renders the power of flight a necessity, and it is on this account that their feathers are so abundant and their wings so large. Besides these, however, there are also other genera of birds that can fly well; all those, for example, that depend on speed for security, and all those again that are of migratory habits. On the other hand some kinds of birds have heavy bodies and are not constructed for flight. These are birds that are frugivorous and live on the ground, or that are able to swim and gain their livelihood in watery places. In those that have talons the body, when stripped of [its feathers and] wings, is small; for the nutriment is con- sumed in the production of these weapons and defensive ap- pliances ; whereas in birds that do not fly the contrary obtains, and the body is bulky and so of heavy weight. In some of these heavy birds the legs are furnished with what are called spurs, which replace the wings as a means of defence. Spurs and talons never co-exist in the same bird. For nature never makes anything superfluous; and if a bird can fly, and has talons, it has no use for spurs; for these are weapons for fighting on the ground, and on this account are an appanage of certain heavy- bodied birds. These latter, again, would find the possession of talons not only useless but actually injurious; for the claws would stick into the ground and interfere with progression. This is the reason why all birds with talons walk so badly, and why 694a.](https://iiif.wellcomecollection.org/image/b24864249_0180.jp2/full/800%2C/0/default.jpg)
