No. 474] 



REACTIONS OF TUBULAR I A 



405 



taining particularly significant results. When treated with dilute 

 onion juice, quinine solution, or acetic acid, the hydranths closed 

 up for a time, and if the solution was strong enough, they weic 

 killed. These substances, unlike meat, produce the same reac- 

 tions as does strong mechanical stimulation. 



Filter paper soaked in meat juice, onion juice, clove oil, or oil of 

 bergamot and held near the hydranth caused no reaction of any 

 part, the animal being apparently insensitive to the resulting very 

 •dilute solutions. 



Colonics of Tubularia were placed in glass tlishes and the effect 

 of a rise or fall in temperature noted. When the temperature of 

 the water was raised above 23° C. most of the animals were inactive, 

 though two in(lividuali> turned the proboscis and opened out the 

 distal tentacles when, at 27.3° ('.. ilicy wwr touched with meat. 

 Xo animal, after having been heated to L*(i ( '. and then cooled again 

 to normal' temperature, survived and ivacted nonnallv. When 

 the water was cooled to about Ml ' C uio>t indivi,hiai> bec^ame 

 iiuictive to in(>at. though a few reacted to tfii> form of .timuhition 



to uv.u- freezing, as iiidi vi. hiafs which had been for half an hour 

 in \vat(>r which was frozen ( 2.2" ('.) at the l)ottom of the dish 



did animals .survive actual fturziiii:' ill the ice. Iti extreme changes 

 of temperature. \hv j)ro\imal tentacle- cea-c to react before the 

 di.stal ones, and this is what might l)e expected from the relative 

 sensitiveness of the latter. 



Local thermal stimulation was attempted witii a l)ent capiilary 



