( 78 ) 



Physiology. — "JVerve influence on the action of the heart. First 

 communication. Genesis of tfie alternating pulse." By Dr. L. 

 J. ,). Muskens. (Communicated by Prof. H. Zwaardemaker). 



(Communicated in the meeting of April 26, 1907). 



Whereas in 1897 ') the writer lias shown, that in the "pulsus 

 regulariter intermittens" of the frog we have to see a result of 

 slowed conduction between sinus and auricle 2 ), or between auricle 

 and ventricle, which was later accepted by Wenckebach 3 ) and recently 

 proved by Mackenzie 1 ) for man, the problem of the pulsus alternans 

 did not profit by the application of physiology on the diseased heart. 

 It is true, that already years ago Traube directed the attention on 

 those types of P. A. in which (he period between the weak beat, 

 and the next stronger one is smaller than between the larger and 

 the smaller contraction, where i. o. w. the greater contraction com- 

 mences too early. But until now only Oehrwall 5 ), W. Straub ') and 

 Trendelenburg 7 ) have gone into the analysis of allied heart-curves 

 of the frog, following up the way which had led to the elucidation 

 of the intermittent pulse. 



It, is clear, that for this analysis we must not join those observers, 

 who think that the explanation of the P. A. by inotropic influence 

 amounts to something more than a simple periphrase of the fact, 

 that every other pulse is weaker. For this misconception brings 

 with it the additional drawback, (hat it cuts off the way for all 

 further analysis. 



In the alternating contraction of the ventricle we have to do not 

 with a simple pathological phenomenon but rather with a general 

 physiological function thai makes its appearance in many circum- 

 stances, which tends to appear as well in vertebrate as invertebrate 

 animals under uncommon conditions. We have here to deal with 

 a capacity of the cardiac muscle which enables (he ventricle to go 

 on with rhythmical contractions even under those abnormal conditions. 



Digitalis dyalisata, injected subcutaneously in the frog, brings 

 about after some time peculiar changes in the heart-beat, after a 



!) Geneesk. Bladen. 1897. 4e Reeks. Bo. 4. p. 77. 



' 2 ) American Journal of' Physiology. Vol. I. 1898 p. 509. 



: ') Wenckebach. Nederl. Tijdschr. v. Geneesk. 1899. I. Biz. 666. 



*) Mackenzie. Britisch. Medical Journal. 24 October 190(3. 



6 ) Oehrwall. Skandinavisches Arch. f. Physiologic Bd. 8. 1898. 



ü ) Straub. Arch. f. experimentellc Pathologic u. Pluirmakologie. B. 45. 



7 ) Trendelenburg. Arch. f. Physiologic (Anal. u. Physiol.) 1903. p. 284. 



