231 



Physiology. — "On the hfurl-rlnjihin. -t''' CoiiinimiiL-atioii. Rearl- 

 nJternntion.'" Hj Dr. S. »e Bokk. (Coiniiiunicatecl by Prof. 

 J. K. A. Wkrtheim S.\lomonson.) 



(Communicated in the meeting of May 25, 1915). 



Physiologists ami cliiiical men ha\c repeatedly discovered an 

 alternating activity of tiie central organ of the circulation of 

 the blood. By ex[ierinients this phenomenon was likewise brought 

 about in different ways. So could Hofi-'mann (i) cause his stopping 

 frog's heart preparations to make for some time alternatingly stronger 

 and weaker pulsations by passing from a slow stimulation-frequency 

 to a quicker. Rümkk (2) made frog's hearts alternate by poisoning 

 them with antiarine. Mu.skkns (3) obtained heart-allernation by 

 poisoning frog's hearts witii digitalisdyalysate. Also by other poi- 

 sons as aconitine and glyo.xyle-acid an alternating activity of the 

 heart is obtained. Gaskell (4) could make the heart-alternation in 

 frog's hearts disappear by Vagus-stimulation, whilst FhéüI'^ricq (5) could 

 produce heart-alternation in narcotized dogs by stimulation of the 

 accelerantes. There exists very little certainty about the explanation 

 of this phenomenon. Muskens. TKENDEi,ENBURfi (6) and Hering (7) on 

 one side attriliute the alternating weak pulsations of the heart to 

 asystoly of part of the ventricle-musculature. Wenckebach (8) con- 

 tradicts this view, he admits likewise this cause for the alternating 

 activity of the heart, but distinguishes moreover another reason for 

 the phenomenon. Clinical experience taught him that p. alternans, 

 apart from its occurrence in paroxysmal tachycardies, is almost 

 exclusively discovered, when the arterial pressure of the blood has 

 increased (chron. nephritis) and the elasticity of the arterial wall has 

 decreased. He considers in this respect alternation more as a pulse- 

 phenomenon than as a heart-piienomenon. Under the influence of 

 little irregularities the filling of the ventricle and the arterial resistance 

 vary alternatingly, so that with constant contractility of the heart- 

 muscle the result of the systoles varied alternatingly. 



My experiments') treat of extirpated frog's hearts: for the alter- 

 nating activity of these this peripheric cause is consequently excluded. 

 If a frog's heart is extirpated and suspended, sometimes alternatingly 

 high and low curves are obtained. I give an exam|)le of this in (ig. 1. 

 (next page). 



') The experiments were made on liibeinated specimens of rana escnlcnla in 

 tlie months of February and Maicli 191."). Pielhninaiy communication pLÜjlislied in 

 the Zontrallblatt tiir Pliysiologie (9). 



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