Generation of Entozoa. 105 
they themselves are the contrivers, of the design the de- 
signers. 
Let us then suppose that a portion either of effused lymph 
or extravasated blood, or any other substance, is about to 
go through the process of converting itself into an intestinal 
worm, and consider what it has to do to effect so complete a 
metamorphosis ; we must suppose that before it assumed its 
independent and distinct life, the first object would be to form 
for itself a mouth and an alimentary canal for its future sup- 
port, a gastric juice of course, and the other necessaries for the 
function of digestion; now even this, in a particle of matter 
destitute of mind or intelligence, as is the peacock’s egg, would 
seem to border a little on the miraculous. 
Well, then, having provided for what many consider the 
most important business of life, the eating function, what has 
it to do next? Why to shake off the homely and ungraceful 
form of its embryotic clot, and assume the elegant gracility 
of an ascarid, or a Spiroptera, or the broad and jointed ampli- 
tude of a tape-worm, the polymorphous structure of a Scolex, 
or the inextricable complexity of a Distoma. 
Having settled this point, the clot has next to regulate its 
growth ; clots are of very various dimensions, but the Hnto- 
zoa are as certainly defined in their limits of magnitude as any 
other class of animals. Well, then, it must be obvious, that 
a clot larger than the species into which it is to be converted 
must fine itself down to the proper size, or if too small, plump 
itself up to the same ; but by what mysterious power it can do 
this I profess not to understand. 
Having got so far, however, in its own creation, what has 
it next to do? To cover itself:with a proper skin ; and in this 
great taste is often exhibited, the tegument of many worms 
offering a very beautiful appearance; and observe the wonder- 
ful phenomenon connected with this. The Deity has spread 
over the surface of animals and plants (I mean such as He is 
acknowledged to have formed) an insensible covering, the 
cuticle, to serve as a protection for the parts beneath. And 
what does the clot do? Why just the same thing; it covers 
itself with a cuticle too; though indeed we need not wonder 
much at this, after its having made for itself an alimentary 
canal and bestowed upon it the function of digestion. 
But the work is not yet completed; motion is not yet pro- 
vided for, a muscular apparatus is therefore next to be fabri- 
cated; first, for the motion of the whole body, and next, for 
that of individual parts ; and so perfectly is this accomplished, 
that it often forms a source of disappointment and vexation 
to the investigator of these animals. Some of the nematoid 
