439 



movements of the animal 1 ciiraiized il lieCorehaiid. Paralysis 

 of tlie skeletal muscles t-aii, in fislies, he elfected onlj' with 

 verj laif^e doses '). For ni\- animals 1 nsed 4 mgr. Inbo cnrari of 

 wliicli, 2 mgr., iiijec'te<l intra|)eritoneallj, was sntlicient to paralyze 

 a 220 gr.-ral. after 7 ininnles. This also pla,ys an intluence upon 

 the vagus-function'), but this inconvenience could readily be obviated 

 by the technique followed, because the synapses of the vagns are 

 restored sooner than the motor innervation. 



After the injection the animal was let alone until no "Slellretlexe" 

 were distinguishable any longer. Also the gills are completely 

 motionless then. At that juncture the cerebrum is severed from the 

 rest of the nervous system by an incision posteriorly along the eyes. 

 After this the cerebrum and the spinal cord are laid bare down to 

 the second gill-hole. Now a straight glass cannula is inserted into 

 the Vena cava dextra, through which the animal, in ventral position, 

 is perfused during some time with Ringkk's fluid, containing 6'/, gr. 

 NaCl, 200 mgr. NaHCO,, 200 mgr. CaCI,, 200 mgr. FvCl '). The 

 surplus of cnrari is hereby gradually washed out. Through a window 

 in the carlilagenons pericardium ') the atrium is fixed to a levei 

 beneath the animal. Now two thin platinum electrodes are fixed, 

 so as to be well visible, at the level where stimulation produces 

 the effect aimed at. With strongly cnrarized animals it sometimes 

 takes rather a long time before any effect can be distinguished. At 

 that moment, however, the animal is perfectly tpiiet, and the 

 experimenter can be sure that only the movements of the heart are 

 registered. In subsequent periods of the perfusion also the contraction 

 of the gills can be distinguished. The electrodes are connected with 

 the secondary coil of an inductorium of Dübois-Reymond, provided 

 with a NKKF-haramer. An accumulator is connected up in the 



*) a. J. ScHiFFEK, Arch. f. Anat. u. Physiol, p. 453, 1868. 



b. i. Steiner, ibid 1875. 



c. Boll, Mon. Ber. d. Kgl. Preuss. Akad. d. Wissensch. Nov. 1875. 



d. J. Steiner, Das americanische Pfeilgift Curare p. 56. 



c. and d. After R. Boehm's article in Handbuch der experimentellen Phar- 

 raacologie II 1. Halfte p. 183. 



'') R. BoEHM, 1. c. p. 202. 



') J. B. Zwaabdemaker, Diss. Utrecht 1922. 



*) When the pericardium is being opened it all at once changes colour. Originally 

 the heart is seen to loom vaguely through the transparent cartilaginous tissue 

 with a bluish tint: after the opening the pericardium shows its own milkwhite 

 colour, while the atrium now appears to lie at tbe bottom of the cavity. Apparently 

 in the pericardium a negative pressure obtains, which of course is lost at the 

 opening, so that the atrium partly collapses. 



