BRAIN PHYSIOLOGY OF WORMS H.IT 



The specimens of Cerebratulus which I used in my 

 experiments were over 50 cm. long and almost, as thick as 

 a ringer. The layman would readily have believed that he 

 \vas dealing with an eel instead of with a worm. The aid- 



~ 



mal lives in the sand. If it is laid upon the sand-covered 

 bottom of the aquarium it soon buries itself in the sand. If 

 the head is amputated from such an animal the head-piece 

 continues to bury itself in the sand when it is not too short. 

 The bodv, <m the other hand, does not make a single attempt 

 to bury itself in the sand. 



IV. EXPERIMENTS ON ANNELIDS 



The Annelids possess besides a fairly complex brain a 

 chain of ganglia which transverse the entire length of the 

 body. We have the experiments of B. Friedlander and of 

 Graber on the function of the central nervous system of the 

 Annelids. 



Friedlander 1 amputated the anterior and posterior seg- 

 ments from angleworms. 



The latter conduct themselves, to put it shortly, as normal ani- 

 mals : they soon bury themselves in the earth. Not so the beheaded 

 worms. Immediately after the operation they execute violent 

 winding motions, perhaps creep about for some time, but usually 

 come to rest after a short time, and can now remain quietly upon 

 moist earth covered with moist filter paper, for days and weeks 

 without, apparently, making 1 any autonomous movements after the 

 wounds have healed. Every stimulus however soon awakens them 

 from their passive condition. They then move about energetically, 

 even creep some distance, but soon fall back into their original 

 lethargy. 



The second series of experiments of Friedlander consisted 

 in excising a small (>"> to 10 mm. long) piece from the abdomi- 

 nal nerve-cord of angleworms. Friedlander had expected 



that the two portions of the worm lying anterior and posterior to 

 the operated point would conduct themselves physiologically during 



('i-iilriilliliill. Vol. VIII. 



