Poison-Secreters. 
1885.] 
671 
whilst to man it is not more formidable than the English 
nettle. 
The possession of poisoned weapons is very common in 
the animal kingdom, chiefly among the Arthropods, much 
more rarely among the Vertebrates. Among the latter it is 
met with only in two of the lower classes, the fishes and 
the reptiles. No warm-blooded vertebrate — in other words, 
no bird or mammal in its normal condition — possesses a 
sting or poison-fangs.* It may be added that no such 
creature is even defensively poisonous. Now as the power 
of secreting and instilling venom, like that of spinning silk, 
would undoubtedly be useful to certain birds and mammals, 
it becomes probable that, as we ascend the animal scale, 
the power of evolving varied chemical compounds and of 
the necessary organs for their use becomes feebler. 
It has been asked, Why are all poison-armed animals 
carnivorous ? Some have asserted that to them poisons are 
of greater service than to plant-feeders, as giving them 
facilities for the capture of their prey. Others have sug- 
gested that poisons may be secreted more readily from 
animal than from vegetable matter. But this dispute is at 
once cut short by the fadt that the honey-bee and its near 
allies, feeding on honey, pollen, and occasionally on the 
juices of fruits and the sweet sap of trees, are also armed 
with stings. 
One of the most remarkable features in the poison-bearers 
is the diversity that prevails not only in the apparatus em- 
ployed, but in the poison itself. Thus in the venomous 
fishes we find certain of the spines of the dorsal fins hollow, 
and placed in communication with a poison-bag or gland at 
their base. In the venomous lizard, Heloderma, we have 
the ordinary teeth. In poisonous serpents there are special 
fangs provided with a dudt, and receiving their supply from 
a gland which is a modification of one of the ordinary sali- 
vary glands. 
We may here consider that the saliva of the dog, when 
modified by a certain disease, becomes deadly, and remember 
Oken’s hypothesis, that the normal saliva of all animals 
seems — in addition to its chemical functions — to have the 
task of extinguishing the molecular life in the animals or 
plants eaten. 
But there is one serpent which, if Australian reports are 
to be depended on, instils its venom in a quite exceptional 
* I reserve the doubtful ease of the Qrnithorrhynchns ; 
