Hydra. 
Z. HYDROIDA. 
103 
momentary and a certain death suddenly follows their capture. How 
this effect is produced is mere matter of conjecture. Worms, in or- 
dinary circumstances, are most tenacious of life even under severe 
wounds, and hence one is inclined to suppose that there must be 
something eminently poisonous in the Hydra’s grasp, as it is impos- 
sible to believe, with Baker, that this soft toothless creature can bite 
and inject a venom into the wound it gives. “ I have sometimes,’' 
says Baker, “ forced a worm from a polype the instant it has been 
bitten, (at the expence of breaking off the polype’s arms,) and have 
always observed it to die very soon afterwards, without one single 
instance of recovery.”* To the Entomostraca, however, its touch is 
not equally fatal, for I have repeatedly seen Cyprides and Daphnise 
entangled in the tentacula and arrested for some considerable time, 
escape even from the very lips of the mouth, and swim about after- 
wards unharmed ; perhaps their shell may protect them from the 
poisonous excretion — The grosser parts of the food, after some hours’ 
digestion, are again ejected by the mouth ; but, as already mention- 
ed, the stomach is furnished with what, in one sense, may be called 
an intestine to which, according to Trembley and Baker, there is an 
outlet in the centre of the base, and the latter asserts that he has, 
“ several times, seen the dung of the polype in little round pellets 
discharged at this outlet or anus.”f 
* Hist, of the Polype, 33 — comp, with 67-8 — “ That insignificant and inac- 
tive insect called the fresh water polypus, of all poisonous animals, seems to 
possess the most powerful and active venom. Small water-worms, which the 
polypus is only able to attack, are so tenacious of life, that they may be cut to 
pieces without their seeming to receive any material injury, or to suffer much 
pain from the incisions. But the poison of the polypus instantly extinguishes 
every principle of life and motion. What is singular, the mouth or lips of the 
polypus have no sooner touched this worm than it expires. No wound, how- 
ever, is to be perceived in the dead animal. By experiments made with the 
best microscopes, it has been found, that the polypus is neither provided with 
teeth, nor any other instrument that could pierce the skin.” Smellie’s Phil, of 
Nat. History, ii. 462. — The fact that fishes cannot be made to swallow Hydrse, 
seems to prove the presence of some irritating quality in the latter.— See Trem- 
bley, Mem. 137. 
f Lib. s. cit. 27. — -He adds, — “ Much the greater and grosser part of what 
the polype eats, is most certainly thrown out again by the mouth, after lying a 
proper time to become digested in the stomach : and, for a good while, I ima- 
gined there was no other evacuation ; but am now convinced, that the finer part, 
in small quantity, is carried downwards through the tail, and passed off that way. 
I believe however there is also another purpose to which this passage serves, 
and that is, to convey a mucus or slimy matter to the end of the tail, for its 
more ready adhesion to sticks, stalks, or other bodies.” 
