IX 



CAEDIAC MUSCLE AND NERVES 



291 



method of multiple suspension from writing levers, attached by threads to 

 different parts of the heart (Fran^ois-Franck, Knoll). Various methods have 



FIG. 124. Oehrwall's tonograph. , Glass bulb to cover outside of heart; b, reservoir of 

 nutrient fluid; c, tonograph for right auricle; <1, tonograph for ventricle; e, f, clips for 

 altering communication with reservoir. 



been adopted in the study of the mammalian heart, independent of any 

 cerebrospinal nervous influence and of the systemic circulation, with the 

 object of more or less completely isolating the cardio-pulmonary circulation 



FIG. 125. Marey's myogi'aph for recording movements of frog's heart in situ. This is a sort of 

 clip formed of two spoons supported by two curved arms at right angles, one fixed, the other 

 movable. The latter carries a horizontal lever, provided at the end with a point, writing on 

 a smoked cylinder. The movable spoon, which is displaced at each systole, is brought back 

 to its original position at each diastole by a fine rubber thread, fixed by a pin to the board on 

 which the frog is fastened. Both spoons are connected with wires, by which various kinds of 

 electrical stimuli can be transmitted to the heart. The exact moment of stimulation is 

 recorded in the cylinder by a Deprez signal. 



(Newell, Martin, H. E. Hering, Hedon and Arrous, and others). Langendorff 

 (1895) was the first who succeeded by the method of direct transfusion through 

 the coronary arteries in keeping the mammalian heart alive for any consider- 

 able time, when completely isolated and removed from the body (under which 



