POISONS. 221 



bring on, not merely a single responsive spasm, as 

 in the impoisoned animal, but a whole series of 

 successive spasms, which are often followed by a 

 paroxysm of twitching convulsions. The condition 

 of exalted reflex irritability is thus exceedingly 

 well marked. Recovery in normal water at this 

 stage is rapid, the motions being at first characterized 

 by a want of co-ordination, which, however, soon 

 passes off. 



5. Veratriiirti. — In Sarsia the first effect of this 

 poison is to increase the number and potency of the 

 contractions; but its later effect is just the con- 

 verse, there being then prolonged periods of quies- 

 cence, broken only by very short swimming bouts 

 consisting of feeble contractions. The feebleness 

 of the contractions gradually becomes more and 

 more remarkable, until at last it is with great 

 difficulty that they can be perceived at all ; indeed, 

 the progressive fading away of the contractions 

 into absolute quiescence is so gradual that it is 

 impossible to tell exactly when they cease. During 

 the quiescent stage the animal is for the first time 

 insensible both to tentacular and to direct stimula- 

 tion of the contractile tissues. That the gradual 

 dying out of the strength of the contractions is not 

 altogether due to the progressive advance of central 

 paralysis, would seem to be indicated by the fact 

 that contractions in response to direct stimulation 

 of the con Tactile tissues are no more powerful, at 

 any given stage of the poisoning, than ai"e either 

 responses to tentacular stimulation or the spon- 

 taneous contractions. Still, as we shall immediately 



