58 RUSKIN M. LHAMON 



fasciculi and in all essential points I found it as described in the 

 literature. 



Although twenty uninjected hearts of beef, calf, and sheep, 

 and others which were injected, were carefully dissected to deter- 

 mine the presence of a bursa, no evidence whatever of the exist- 

 ence of such a structure was obtained. The sheath and bundle 

 with its larger and smaller branches could not be freed from its 

 bed until the strand of connective tissue uniting it with the under- 

 lying musculature had been broken. Between the bundle and the 

 heart muscle there seemed to be a line of cleavage in places where 

 the connecting trabeculae were very fine and consequently broke 

 easily, yet, these fine connections were always present. Under 

 the cartilaginous or the bony septum of the beef heart, where 

 the main bursa was located by Curran, a considerable amount of 

 loose connective tissue was constantly present in the hearts which 

 I examined, but a definite and preformed bursal space was never 

 found. At the point where the left branch of the main bundle 

 passes out from under a layer of muscle to lie immediately 

 beneath the endocardium, a slight depression was noted usually 

 in the endocardial layer. When the endocardium was carefully 

 dissected off from this place and the edge of the layer of muscle 

 lifted up with a forceps, very fine trabeculae were constantly seen 

 connecting the muscle with the sheath of the bundle. Since 

 this was the place where Curran located the main bursa, and 

 where he stated the greatest friction existed between heart muscle 

 and bundle we should expect some evidences of a bursa here. If, 

 as Curran seems to think, a protective mechanism be necessary 

 this loose connective tissue sheath could perhaps serve for pro- 

 tection of the bundle against the forcible impact of the surround- 

 ing structures. 



A careful examination of the stained section from uninjected 

 specimens failed likewise to reveal any space. On the contrary, 

 the sections showed a thick layer of connective tissue enclosing the 

 bundle. On the one hand, this layer passed over into the con- 

 nective tissue of the cardiac muscle; on the other, it formed the 

 envelope and framework within which the bundle lay embedded 

 so that each strand had its sheath. The stained sections further 



