VENOMS IN THE ANIMAL SERIES 287 
plates, and motor and sensory nerves are spared; the nervous 
centres alone are attacked, especially the encephalon. The animal 
dies without convulsions. 
Sea and fresh-water fishes (golden carp) are very sensitive to 
this venom ; warm-blooded animals are refractory. It is therefore 
probable that, in the species of Murex, the purple gland is a poison- 
gland serving for defence, or for the capture of the prey upon which 
these molluscs feed. 
Among the Cephalopods, the Octopods (Octopus vulgaris, 
common octopus, Hledone moschata, musky octopus, of the 
Mediterranean) possess two pairs of salivary glands, a small 
anterior pair, and a posterior pair of considerable size. 
The Decapods (cuttle-fishes [Sepia], &c.), have only posterior 
salivary glands, of smaller dimensions in proportion to the size of 
the body. 
On being crushed and macerated in water, the anterior glands 
yield a limpid and slightly acid juice ; the posterior glands produce 
a viscid, ropy fluid, filterable with difficulty and neutral. The 
latter has an immediate paralysing effect upon Crustacea. It 
contains a substance of a diastasic nature, precipitable by alcohol, 
and destructible by heating for an hour at 58° C. 
Owing to the poisonous properties of this juice, Octopods 
succeed in overpowering large prey, such as lobsters and crabs. 
Once they are seized by the tentacles of the octopus, or cuttle-fish, 
a bite inoculates these animals with venom that immediately 
destroys their power of movement, and the Cephalopod is able to 
continue its meal in perfect security, without having to fear the 
pincers of its prey. 
An experimental study of this venom has been made by A. Briot,! 
who found that crabs are very sensitive to it, while rats, frogs, 
rabbits, and fish do not appear to experience any inconvenience. 
! Comptes rendus de la Société de Biologie, February 25, 1905. 
