256 THE REV. THEODORE WOOD, F.E.S., ON 
1. WE know, of course, as a fact ascertained beyond all 
possibility of question, that the nervous system, in different 
animals, varies enormously, both in extent and in sensibility. 
At the one extreme of the scale we have man, with almost 
every part of his body so permeated with sensory nerves 
that the slightest jury, under normal conditions, is immedi- 
ately felt, while their sensitiveness is so great that even a 
mere local chill may be productive of prolonged and almost 
unendurable agony. At the other end we have the jelly-fish, 
with a nervous organization so scanty and imperfect, that 
until the researches of Ehrenberg proved its existence, its 
presence was not even suspected. Of a corresponding 
organization in creatures lower in the natural scale than the 
jelly-fish we know little or nothing, save that the tentacles 
of certain zoophytes—such as the sea-anemones—appear very 
sensitive to iritation, although the organs of special sense 
are rudimentary im the extreme. 
But it does not, of course, follow that even in the jelly-fish, 
in which we know that nerves exist, anything at all 
approaching to the sensation which we call pain can be in 
any degree experienced. It is true, no doubt, that many of 
these lowly organized creatures will contract their tentacles 
if any outside object should come into contact with them. 
But, on the other hand, we see a precisely similar pheno- 
menon under similar circumstances in the case of the well- 
known sensitive plant, im which, of course, there is no 
question of a nervous system, properly so-called; far less of 
any sense of pain. And the few nerves which have been 
detected in the jelly-fish are almost certainly of a strictly 
motor character. Most of these animals, as is well-known, 
possess some slight power of altermg the form and the 
relative position of their discs; and this process, which is un- 
doubtedly due to muscular contraction, necessarily implies 
the existence of motor nerves. Examination proves, too, 
that the whole of the nervous system, as at present known, 
is in these creatures more or less intimately connected with 
the muscular fibres; for the latest investigations tend to 
prove that the band of sensitive nerves described by Haeckel as 
surrounding the circular canal in the ball-shaped Medusa, is 
absolutely non-existent. And it is scarcely necessary to say 
that no vestige of evidence has ever yet been offered which 
would support in these remarkable animals an argument for 
the existence of the sense of pain. 
All available testimony, indeed, seems to show that im the 
