The fibro-cartilaginous system appears to have nearly the same relations with the digestive juices, as the fibrous and cartilaginous systems, of the nature of which it partakes; it is altered with difficulty by those juices in a crude state. Boiling, by softening, makes it yield more to their action; it becomes then more digestible. In general, it gives an aliment less proper for nutrition, than that furnished by many other systems. II. _Parts common to the Organization of the Fibro-cartilaginous System._ The common organs of the fibro-cartilages are not very conspicuous; the cellular texture is in small quantity, and so compact as hardly to be distinguished; maceration however renders it apparent. But little blood enters their vascular system in the ordinary state; I convinced myself of this by dissecting an animal killed for the purpose by asphyxia, a disease in which the blood accumulating in the capillaries intermediate to the arteries and the veins, towards the head especially, renders these capillaries very evident; but in inflammation, which is however rare in the fibro-cartilages, they are very much injected. We can trace no nerves in them. ARTICLE THIRD. PROPERTIES OF THE FIBRO-CARTILAGINOUS SYSTEM. I. _Physical Properties._ Elasticity belongs essentially to this system. This property is very evident, 1st, in the fibro-cartilages of the ears, when we bend them; 2d, in those of the nose, when twisted in various directions; 3d, in those of the trachea, when we compress them, or after having cut them longitudinally, we separate the edges of the division, as is done in tracheotomy, when the object is the extraction of a foreign body. It performs an important use in the kind of vibration which is made in the first in the perception of sounds, in the second in the production of the voice; 4th, it is in virtue of their elasticity, that the articular fibro-cartilages serve as a kind of cushions which favour, by contracting and expanding, the motion of the osseous surfaces to which they correspond; 5th, that those of the vertebræ in particular, flattened during the day, re-act during rest, and thus make the stature in the morning something more than it is in the evening; 6th, finally in the sliding of the tendons upon their fibro-cartilages, the elasticity of these last favours the motion in an evident manner. This elasticity of the fibro-cartilages is united to a remarkable suppleness; they bend in all directions without breaking. By the first property they resemble especially the cartilaginous system; by the second they approximate the fibrous. It is not astonishing that being intermediate to these two systems in their texture, they should be so also in their properties. II. _Properties of Texture._