The larynx is furnished with four principal arteries, called laryngeals; two coming from the external caro tids, and two from the subclavian arteries. Its nerves are derived chiefly from the par yagum.
The larynx is much larger in men than in svomen, nearly in the proportion of two to one ; and the angular projection is much flatter in the female sex, while the atlantal cleft is more superficial. These differences be tween the larynx of the male and that of the female, either are not observed, or are much less evident in the 'etus, and in early childhood. They do not sensibly take place tiii towards puberty. It is at this time that the larynx of the male sex begins to acquire its proper size and prominence ; and at this period, too, as is well known, the voice becomes full and manly. In old age, the car tilages of the larynx usually become ossified, whence they are less elastic, and the membranes are not so move able as in the earlier periods of life.
The muscles that serve to regulate and modify the human voice are numerous, consisting not merely of those that are attached to the larynx and the tongue, but comprehending almost all1 t.iose which are connected with tile (is hyoidcs or the lips. They must be enUnle• rated as follows: A great variety of morbid appearances has been ob served in the organs of respiration, and the cavity in which they are contained ; and these merit particular notice, as from them we derive much useful information respecting the seats and causes of some of the most distressing afflictions to Nvhich the human frame is sub ject. We shall begin with the morbid appearances that are usually observed within the cavity of the chest, and about its investing membrane. The fluid that naturally oozes into the chest from the central surface of the pleura, is often unusually increased in quantity, forming dropsy of the chest, or hydrothorax. Purulent matter is also occasionally found accumulated in this cavity, con stituting the disease called empyema. The pleura is very frequently seen in a state of inflammation, and in these cases, adhesions, more or less extensive, are found to have taken place between the pleura that lines the ribs, and that which covers the lungs. These adhesions are exceedingly common, and are always a mark of pre ceding inflammation. In a few cases, some portion of the pleura appears in a bony state, or ossified, and some times it is found preternaturally dry.
The lungs are very commonly observed affected with inflammation or its consequences. Very often they are seen extremely red and firm, and their vessels turgid with blood. Frequently ulcers are seen to have been formed in some part of the substance of the lungs. These are called vernier, and are sometimes confined within a close cavity, while at others they communicate with the windpipe, or with the cavity of the chest. Nu merous instances occur where the lungs contain a number of roundish firm white bodies, interposed tLtough their substance. These are called tubercles, and are situated chiefly in the cellular substance that connects the air-cells. These tubercles are generally about the size of a small pea, though their magnitude rics considerably, and often they are not larger than small pins' heads. They are sometimes separate from each other, but more frequently they appear in clusters. They are often seen in a state of ulceration, containing a thick curdled pus. Sometimes water is found accumu lated in the substance of the lungs, forming a peculiar modification of hydrotkorax. The air-c elk have been seen morbidly enlarged, and sometimes ruptured, so that a number of them are formed into one cas ay. In a few rare case, a portion of the lungs has been found ossi fied, and more frequently earthy concretions are met with in their substance. Scrofulous tumours have been seen attached to the lungs, and hydatids arc not un frequently found about the lungs or the bronchi.
The cartilaginous rings composing the sternal part of the windpipe, arc sometimes seen ossified, and the whole tube has been observed contracted in its diameter, and thickened in its substance. The fibrous membrane that corers the peripheral surface of the windpipe, is often seen inflamed, especially next the gullet. But morbid appearances are more frequent in its central membrane, which is not uncommonly more or less inflamed, and is sometimes lined with a layer of a yellowish pulpy mat ter, that may be easily separated from the membrane. This is the appearance so commonly described in the disease called croup. This layer of adventitious matter sometimes forms a complete cylinder of considerable thickness, but in other cases parts of it appear to have been separated from the membrane, and spit up by coughing.