146 THE SINO-VENTRICULAR BUNDLE. 



system." This term is still used by many authors, but feeling that a morphological 

 one must be used as long as the question of function is still in doubt, in 1908 I 

 employed the name "sino- ventricular bundle." By this term we definitely 

 commit ourselves only to the fact that the bundle forms an anatomical connection 

 between the sinus region and the ventricles. The terms "conductive system" and 

 "atrio-ventricular bundle" still have their place, as I shall indicate later. 



It may be noted that most of our anatomical text-books take little cognizance 

 of the change of our knowledge on this subject and still persist in using the term 

 "bundle of His." It has already been pointed out that His's description is far from 

 correct. I may add here that considerable skepticism as to the correctness of the 

 observations of His existed in the mind of his father and of other mature anatomists 

 when I made my first observations under Professor Spalteholz, in 1903, and it was 

 for this reason that the problem was undertaken again. Kent's (1893) original 

 description is far more correct in the light of our modern investigations than was 

 that of His, and the bundle has been named the "bundle of Kent" by some authors; 

 but we should recognize the fact that it was His, who by experimental methods, was 

 the first to attempt to prove that all impulses from atria to ventricles pass by way 

 of the bundle. 



In my notes, made in 1903, when I began my studies on the subject, I find the 

 following review of Kent's article: 



"In his figure on p. 244, it seems to me that he mistakes the Purkinje fibers for fibers 

 of the myocardium. His description of the cells standing between muscle and connective 

 tissue reminds me also of these (Purkinje fibers)." 



This note was made five years before the appearance of Tawara's monograph, 

 which showed indisputably that the Purkinje fibers represented the end-ramifica- 

 tion of the atrio-ventricular bundle. Recently I read the Proceedings of the 

 Physiological Society of November 12, 1892, which I had previously overlooked, 

 and I was much interested in the report of Kent's paper before the society: 



"Between the auricle and ventricle and lying in the connective-tissue ring are modified 

 muscle cells, usually spindle-shaped, nucleated, granular, becoming extremely narrow in 

 parts and then swelling out again, transversely striated, branched, and usually connected 

 into a network. These cells are somewhat rudimentary in the case of the rat and are 

 very well developed in the monkey. In the latter animal they exist as a complete network, 

 permeating the fibrous connective tissue of the groove and extending through from auricle 

 to ventricle. Upon approaching the groove the normal cardiac fibers split up into similar 

 fibers and become connected with the network of cells lying in the fibrous tissue." 



This shows even more conclusively that Kent did recognize the difference in 

 appearance between the bundle-fibers and the heart-muscle fibers and also saw the 

 ventricular transitions between them, although he did not recognize that the end- 

 ramifications of the bundle really represent the Purkinje fibers. His descrip 

 tion, however, lacked the dogmatism which seems so essential for the general 

 acceptance of a new idea. Thus he states in a summary: 



"It would appear* then, that the fact of two masses of muscle being joined together 

 by fibrous tissue is in itself no argument against the muscular continuity of such masses, 



*The italics are mine (R. R.) 



