GENERAL PHYSIOLOGY OF MUSCLE AND NERVE. 89 



touch a revolving cylinder, the surface of which is covered with paper black- 

 ened with lampblack. If, when the cylinder is revolving, one end of the 

 cle be stimulated, the record will 

 show that the lever resting on that 

 part is the first to move, making 

 it evident that that part of the mus- 

 cle begins to thicken first, and that 

 the contraction does not begin at 

 the further extremity of the mus- 

 cle until somewhat later. The re- 

 cord given in Figure 30 was ob- 

 tained in a similar experiment, but 

 one in which the contraction of 

 the muscle was registered by the 

 pince myograpUque and recording tambour of Marey (see Fig. 31). 



Bernstein l measured the rate at which the irritating process is transmitted 

 along the muscle by recording the latent period, the time elapsing between the 



FIG. 30. Rate of conduction of the contraction pro- 

 cess along a muscle, as shown by the difference in the 

 time of thickening of the two extremities. The tuning- 

 fork waves record T J second (after Marey). 



FIG. 31. Method of recording the rate of passage of the contraction process along a muscle (after 

 Marey). The movements of the muscle are recorded by means of air-transmission. The pince myo- 

 graphique consists of two light bars, the upper of which acts as a lever, moving freely on an axis sup- 

 ported by the lower. When the free end of the upper bar is raised, the other end presses down on a 

 delicate rubber membrane which covers a little metal capsule, which is carried on the corresponding 

 extremity of the lower bar. The capsule is in air-communication, by a stiff-walled rubber tube, with 

 another capsule which is similarly covered with rubber membrane. A light lever is connected with the 

 membrane of the second tambour, and records its movements on the surface of a revolving cylinder. 

 The muscle is placed between the free ends of the bars of the pince myographique, and, when the muscle 

 thickens in contraction, it raises one end of the lever, depresses the membrane at the other end, and 

 drives air into the recording tambour, and thus, by automatically raising the writing-point, records its 

 change in form on the cylinder. 



moment of irritation and the beginning of the contraction (see p. 101). A 

 lever was so connected with one end of the muscle as to record the instant that 

 it began to thicken. The muscle was stimulated in one experiment at the end 

 from which the record of its contraction was taken, and in another immediately 



1 Untersuckungen iiber die elektrische Erregung von Muskeln und Nenen, 1871, p. 79. 



