POISONS. 251 
quent, till at last they altogether die away. Irrita- 
bility, however, still continues for a time—a nip 
with the forceps being followed by a bout of rhyth- 
mical contractions. Death occurs in several hours 
in strong and irregular systole. 
“Tf the exposure to sea-water has only lasted two 
minutes, a similar series of phenomena is presented, 
except that the spontaneous twitching movements 
supervene in much less time than twenty minutes. 
But an exposure of one minute may determine a 
fatal result a few hours after the Medusa has been 
restored to fresh water. 
“Contact with sea-water causes an opalescence 
and eventual disintegration of the tissues, which 
precisely resemble the effects of fresh water upon 
the marine Meduse. When immersed in sea-water 
this Medusa floats upon the surface, owing to its 
smaller specific gravity. 
_ “Jn diluted sea-water (fifty per cent.) the pre- 
liminary tonic spasms do not occur, but all the 
other phases are the same, though extended through 
a longer period. In sea-water still more diluted 
(1 in 4 or 6) there is a gradual loss of spontaneity, 
till all movement ceases, shortly after which irri- 
tability also disappears; manubrium and tentacles 
expanded. After an hour’s continued exposure, 
intense rigor mortis slowly and progressively de- 
velopes itself, so that at last the bell has shrivelled 
almost to nothing. An exposure of a few minutes 
to this strength places the animal past recovery 
when restored to fresh water. In still weaker mix- 
tures (1 in 8, or 1 in 10) spontaneity persists for a 
