220 FRANKLIN P. MALL 



bundles of the ventricles of the heart. Throughout this paper 

 I shall speak of a vortex of the right ventricle, and the vortex, 

 or vortex of the left ventricle, to designate the vortex of the 

 B N A. 



That the main superficial muscle bundles enter the heart at 

 its apex to spread out on the inside of the ventricle has been 

 known to anatomists since the time of Borelli, whose account 

 of the contracting mechanism of the heart muscle is the one mj- 

 study strives to revive. E. H. Weber has given us the most 

 satisfactory account of the arrangement of the muscle bundles 

 of the ventricle and his description should be studied by all who 

 wish to become familiar with the subject. It is one of the most 

 satisfactory accounts that has yet appeared. i* Weber pointed 

 out clearly that the superficial and inner muscle bundles radi- 

 ated spirally from the apex towards the base of the heart, but 

 in opposite directions. In viewing the heart as an object it is 

 found that they pass from left to right towards the apex on the 

 outside of the heart, and from right to left on the inside. Be- 

 tween these two layers there is a middle layer which according 

 to Wolff can be broken into an outer sheet with fibers more nearly 

 parallel to the outer layer of muscle bundles and an inner sheet 

 in which the direction of muscle bundles corresponds more nearlj^ 

 with those of the inner layer. So the statement made by Lud- 

 wig that any cube of heart wall extending from the pericardium 

 to the endocardium is composed of fibers on the outside which 

 are at right angles to those on the inside, rests upon a sound 

 anatomical basis. When such a block is torn to pieces it is fur- 

 ther found that the fibers on one side gradually rotate in position 

 as they are followed to the other. 



Weber's studies of the musculature of the heart, especially 

 that of the left ventricle, do not deal with the course of the fibers 

 in the septum in a satisfactory manner, and he expressly states 

 that this portion of the heart must be unraveled before a com- 

 prehensive view of the whole system of muscle bundles will be 

 ol)tained. In this region the many studies of Casper Friedrich 



'^ 'llic larffc inodiTii text Ijooks with t lie t'X('t'])t ioii of Qiiain's Anatomy ignore the 

 musculature uf the lieart altogether or give but a meager aecount oi' this subje(!t. 



