NERVOUS TRANSMISSION 99 



vertebrate or an arthropod. In fact, the condition in the 

 higher animals that seems most nearly to resemble this 

 state of profound tonus in sea-anemones is that which fol- 

 lows strychnine poisoning or the poisoning from the bacil- 

 lus of tetanus, a muscular spasm which, however, often 

 results in death. 



The recovery of a sea-anemone from this state of ex- 

 cessive muscular tonus is slow and gradual. It depends 

 upon a reduction of the tonus, which exhibits itself in the 

 form of a general relaxation of the musculature followed 

 by a slow filling of the digestive cavity of the animal with 

 seawater whereby it eventually assumes its distended 

 form. This is carried out by the action of the ciliated 

 siphonoglyphs through which currents of water are led 

 into the interior of the animal. The process of recovery 

 is, therefore, a relatively slow one as compared with the 

 operation of contraction by which the water under rather 

 high pressure is literally squirted from the animal's 

 body. 



Thus the character of this response illustrates well the 

 nature of the nerve-net, for it shows that from any single 

 spot on the surface of the actinian's body practically its 

 whole musculature may be brought into excessive but 

 normal contraction. Is it possible through this net to 

 affect one set of muscles rather than another or is the net 

 an open conducting system leading as freely in one direc- 

 tion as another? Theoretically such a diffuse condition 

 has for some time been assumed, but it is questionable 

 whether in even the simplest nerve-nets such an undiffer- 

 entiated state really exists. The method of stimulation 

 used in the preceding experiments, that by a fine glass rod, 

 though apparently delicate, is in reality most harsh and 

 unnatural as compared with normal stimuli for such ani- 



