ACTION OF FLUIDS ON THE HEART. 



103 



ligature is tied over it around the auricle, or it may be the sinus venosus. Thus 

 the auriculo-ventricular ganglia and other nervous structures remain in the pre- 

 paration. This was the heart preparation employed by Luciani and Rossbach. 

 (2.) In the " heart- apex" preparation the cannula is introduced as before, but the 

 ligature is^tied on it on the ventricle, several millimetres below the auriculo- 



/! 



Fig. 33. 



Roy's apparatus or tonometer for the heart h, heart ; o, air-tight chamber ; 

 p, piston; I, writing lever. 



ventricular groove, so that this preparation contains none of the auriculo-ventricu- 

 lar ganglia, and, according to the usual statement, this part of the heart is devoid 

 of nerve ganglia. This is the preparation which was used by Bowditch, Kronecker 

 and Stirling, Merunowicz, and others. The first effect of the application of the 

 ligature in both cases is, that both preparations cease to beat, but the "heart" 

 usually resumes its rhythmical contractions within several minutes, while the 

 "heart-apex" does not contract spontaneously until after a much longer time 

 (10 to 90 mins.). 



If the " Heart- Apex " be filled with a 0*6 per cent, solution of common salt, 

 the contractions are at first of greater extent, but they afterwards cease, and 

 the preparation passes into a condition of "apparent death;" while if the action 

 of the fluid be prolonged, the heart may not contract at all, even when it is 

 stimulated electrically or mechanically. It may be made, however, to pulsate 

 again, if it be supplied with saline solution containing blood (1 to 10 per 

 cent). The "stille" or state of quiescence may last 90 mins. (Kronecker and 

 Merunowicz). If the ventricle be nipped with wire forceps at the junction of the 

 upper with its middle third, so as to separate the lower two-thirds of the ventrical 

 physiologically but not anatomically from the rest of the heart, then the apex will 

 cease to contract, although it is still supplied with the frog's own blood (Bernstein, 

 Bowditch). The physiologically isolated apex may be made to beat by clamping 

 the aortic branches to prevent blood passing out of the heart, and thus raising the 

 intracardial pressure. The rate of the beat of the apex is independent of and 

 slower than that of the rest of the heart. This experiment proves that the 

 amount of pressure within the apex cavity is an important factor in the 

 causation of the spontaneous apex beats (Gaskell). If blood-serum, to which 

 a trace of delphinin is added, be transfused or "perfused" through the heart, 

 it begins to beat within a minute, continues to beat for several seconds, and 

 then stands still in diastole (Bowditch). Quinine (Schtschepotjew) and a mixture 



