106 University of California Pithli cations in Zoology [Vol. 18 



anesthetized, it is necessary to assume that the impulses run through 

 the cord for a considerable distance rather than through one ganglion 

 as Friedlander supposed. 



MATERIALS AND METHODS 



Materials. — Several species of worm were used for these experi- 

 ments. The large garden worm, Heloclrilus caliginosa, was favorable 

 material owing to its size. The small dung worm, Allolohophora 

 foetida, was also very convenient material because of the ease of 

 obtaining the material during the winter. No difference was observed 

 in the reactions in these worms. Unless specially noted the experi- 

 ments recorded will refer to the larger worm. Helodrilus. 



Methods. — Biedermann's (1904) method of anesthetizing a cer- 

 tain portion of a worm by use of nitric acid or chloroform, as described, 

 had the effect of killing any peripheral nerve endings present in the 

 part and of impairing the muscle cells. It left the anterior and pos- 

 terior portions connected, however, by a functioning nerve cord, still 

 intact, except that no stimuli applied to the treated epithelium were 

 effective in setting up reflexes. 



It was suspected by Biedermann that as locomotion took place the 

 posterior part was acting in coordination, not only because it was 

 connected to the anterior, as Friedlander might have supposed from 

 his string experiment, but that there was some real nervous influence 

 transmitted by the cord in the inert middle section. In order to test 

 this point fully, he pinned the middle anesthetized portion to a cork 

 plate to remove the factor of tension, when it was found that the 

 posterior portion still made movements coordinated with those of the 

 anterior piece. This established beyond a doubt that transmission 

 did take place over a longer section of the cord than the earlier in- 

 vestigators had deemed necessary and showed the more important part 

 played by the nervous system. 



In developing a method of anesthesia to test farther the matter of 

 transmission, it seemed to me desirable to find some means of blocking 

 reflexes in the middle area, and yet it was also quite necessary at the 

 same time to leave the muscle tissue and the central nerve cord intact, 

 only the peripheral nervous system being eliminated. The method 

 developed was quite different from that of Biedermann. The worm 

 was placed on a glass plate slightly moistened with water, so that it 

 was slippery. A small four-drahm homeopathic vial containing some 



