1918] Bovard: Nervous Impulses in the Earthworm 117 



24 J 250 



post. 



time in 

 1/5 sec. 



ant. 



Numbers refer to time of day animals were tested. 

 Arrow indicates stimulus given to the anterior end. 



Fig. 8. Experiment 190. Stovaine injected into middle section of worm, 

 four segments affected. Lower curve registers the movements of anterior end 

 and upper curve those of the posterior end. At 2:41 p.m. the coordination 

 between anterior and posterior parts is not normal, and at 2:50 p.m. the giant 

 fiber action is lost. Stimulation at the arrow fails to give a reaction in the 

 posterior part. 



A represents ordinary locomotor activities. 



B represents giant fiber action. 



but as soon as the effects begin to wear off, the coordination between 

 the two parts becomes more and more complete until finally the 

 anterior and posterior parts are again acting in perfect rhythm (fig. 9) , 



The supposition in this case is that stovaine acts on tissue of earth- 

 worm as it does in the vertebrates, where it has no effect on muscle or 

 nerve endings but acts only as a "block" on nerve fibers. The effects 

 of the drug were kept localized to small sections while anteriorly and 

 posteriorly all the normal reactions could be obtained. 



Conclusion. — The nerve-free preparations, the graphic records of 

 movements before and after the nerve was cut, and the physiological 

 block established by stovaine, all go to show that the locomotor impulses 

 travel considerable distances in the cord. This work confirms the 

 results obtained by Biedermann but by quite different methods. The 

 most important aspect of these results is the demonstration that 



