TBANSACriONS OP THE SECTIONS. 



683 



2. Convoluted arterial plexuses, similar to those in tlie thorax 

 and vertebral canal of this and other cetaceous animals, (in 

 which situation they were particularly described by Mr. Hunter 

 in the Philosophical Transactions for 1787,) are formed also by 

 several arteries of the neck and head. 



3. Several arteries show a tendency to divide into long parallel 

 branches, of which the arteries of the bladder, vagina, and ute- 

 rus offer a striking example. 



4. The mode of division of the posterior or caudal portion of 

 the aorta differ somewhat from the description given by Cuvier, 

 in as much as that .vessel is not wholly resolved into small 

 branches, which unite to form it anew, but is only diminished 

 in size, and concealed in the midst of a plexus formed by its 

 branches, from which, after becoming larger, it again emerges. 



5. The veins as well as the arteries present in several regions 

 of the body a plexiform arrangement, and in some situations 

 plexuses of both kinds of vessels are associated or mixed with 

 one another. 



6. The artery corresponding to the internal carotid, which at 

 its origin is as large as in man, diminishes in a tapering manner, 

 and without giving off branches, till it enters the skull, where it 

 is scarcely thicker than a pin. 



On the Use of the Omentum. By il/r. Dick. 



From a comparison of the structure of this organ in the horse 

 and in the sheep, — in the former the omentum being small, 

 the intestines are fixed, and undergo comparatively little change 

 of place, — the author inferred that the omentum might serve, 

 by interposition between the intestines and abdominal parietes, 

 to facilitate motion. 



On the Infiltration of the Lungs with Mack Mattel', and on 

 Mack Mxpectoration. By Dr. W. Thomson. 



The author particularly noticed the cases of this singular in- 

 filtration, occurring in coal-miners, iron-founders, and other 

 workmen exposed by their employment to the inhalation of 

 carbonaceous gases and powders. He referred to a variety of 

 published and unpublished communications on the subject, and 

 exhibited a number of preparations and drawings illustrative of 

 the appearances, nature, and seat of the disease. 



