258 OBSERVATIONS 



thefe mufcles laid obliquely, and decufTating each other, I ufed 

 to diiTecT: fome portions of the two layers, in fuch a manner as 

 to reprefent oblique mufcles, with their origins at a diftance 

 from each other, but their infertions meeting in a point, or 

 with their infertions, as well as their origins, at a diftance from 

 each other. 



In the back part of the fpine, I very particularly demon- 

 flrated the obliquity of many of the mufcles, fome of which 

 are called femifpinales, becaufe one end of them only is fixed 

 to the fpinal proceffes, and the fibres paffing obliquely, the 

 other end of them is fixed to the tranfverfe proceffes, or other 

 parts of the neighbouring vertebrae. 



In the extremities, I not only carefully demonftrated the 

 obliquity of the flefhy fibres, in the half and whole penniform 

 mufcles, but pointed out their connection with their tendinous 

 aponeurofes, the different direction of the tendinous and flelhy 

 fibres, and the ufes of the aponeurofes and tendinous (heaths y 

 and that, by means of the fheaths, there was fo little difference 

 between the length of the mufcles in the bended and extended 

 ftate of the member, that fhort flelhy fibres, efpecially when 

 placed obliquely, could produce a very extendve motion. 



But in treating of particular parts, I dwelt chiefly on the 

 ftructure and effecls of the intercoftal mufcles, as a variety of 

 opinions concerning their operation has, in the courfe of the 

 laft hundred years, been propofed, and as no author had ex- 

 plained the reafon of the obliquity of their fibres, nor of their 

 being difpofed in two layers of decuffating fibres. 



That their ftructure might be fully underftood, I firft laid 

 bare the furface of the external intercoftal mufcles, and between 

 the next two ribs, I cut off the external intercoftals, to fhew the 

 internal, as in T. 3. fig. 4. 



In another fpace, I (hewed a fmall bundle of the external 

 intercoftal, decuffating a fimilar bundle of the internal inter- 

 coftal, 



