52 



PHYSIOLOGY 



CHAP. 



certain modifications in the methods of investigation, and obtained 

 results which frequently contradicted previous conclusions. His 

 first experiments were carried out on the rabbit, with direct and 

 indirect excitations of the muscles once a second. The tendon of 

 the muscle was not separated from its insertions, but the resistance 



Fio. 31. Ergogram of rabbit's gastrocnemius, loaded with 1150 grms. (maximal weight), 

 sciatic was excited every two seconds. (Treves.) 



The 



of the weight was transmitted to the muscle by means of the 

 natural bony lever of the rabbit's leg, the end of which is connected 

 with the writing point of the ergograph. He used maximal 

 tetanising stimuli of very brief duration, in imitation of voluntary 

 impulses. Before taking the ergograph curves, Treves ascertained 

 at what weight the muscle was able to contract, with maximal 



FIG. 32. Ergograph tracings from same muscle as preceding figure. The initial maximal weight was 

 gradually diminished so as to determine the maximal terminal weight at which the rhythmic 

 lifts no longer make a descending curve, but form a horizontal line (constant phase of ergogram). 

 (Treves.) 



excitation, so as to serve up maximal work. As he did away with 

 the supporting screw of Mosso's ergograph, the weight pulled 

 continuously upon the muscle, and not merely during contraction. 

 Under these conditions Treves obtained an ergogram in which 

 the height of the contractions regularly diminished, but more and 

 more slowly, till they became almost inappreciable, and below 



