942 



own researches we always took care to experiment only with unfati- 

 giied, fresh muscles. 



Under these conditions we ought to expect the critical frequency 

 for a complete tetanus to be a constant one, not liable to variation 

 under the influence of pathological changes. If such be not the case 

 we can only conclude that either the form of the complete single- 

 twitch-myogram, oi' perhaps only its descending part, must be equally 

 signiticant for the critical frequency as the ascending part of the 

 curve. There is a simple way of solving this question. 



A few years ago Dr. dk Boer showed that the tonns-mechanism 

 greatly affects the general form of a single-twitch myogram in a 

 frog's muscle. In a fiesh muscle preparaplihn separated from the 

 spinal cord we get only a short myogram, with a rapidly descending 

 part. But in a muscle connected with the nervous system the myo- 

 giam, and especially its descending part has a much longer duration. 

 The descending line generally shows a secondary elevation — which 

 is often smaller, but may be even laiger than the primary apex — 

 called after its discoverer Funke's "nose". Dk Boer demonstrated 

 that this secondary is a true reflectory tonus-oscillation, which im- 

 mediately vanishes after cutting the grey rami communicantes from 

 the sympathetic nervous system to the motor plexus. With any 

 variation of the peripheial tonus mechanism the ascending part of 

 the myogram remains unchanged, whereas the descending part is 

 altered in form. We might now ask if the descending part of the 

 myogram does influence the critical frequency for the complete 

 tetanus and we can answer this question by examining the influence 

 of muscle tonus on this critical frequency. A probable connection 

 between the two has been advocated among others by Yeo and Cash, 

 who termed tonus the cement connecting the separate muscle twitches 

 so as to form a complete tetanus. Botazzi considers tonus as the 

 substratum on which tetanus is built. Also Coustensoux and Zimmern 

 state that a direct connection does exist between tonus and the 

 genesis of the complete tetanus. 



We have examined a large number of healthy persons with a 

 normal muscletonus as well as clinical cases in which the tonus 

 was either diminished or increased. 



The graphic recording of the tetanic muscle contraction caused 

 some difficulty, when as a matter of fact only records of variations 

 in thickness of the muscles could be made. This demanded the 

 greatest cai-e in the consti-uction and use of the recording styluses. 

 Finally by reducing the lever-magnification to 6 times, and by using 

 a lever of only 60 millimeters length and a weight of 11 milligrammes 



