ON ENTOZOA. 553 
tinal canal of an animal which had been dead for several 
days. The ascarides and distome may be preserved alive 
for many days. Rudolphi even speaks of one species of 
ascaris, the A. spiculigera, which was resuscitated, after being 
extracted from the intestine of a bird, which had been for 
twelve days in very strong spirits of wine. 
We are in possession of no proof that they can reproduce 
any individual part which may have been lost or taken 
away. 
We may say, in a general manner, that all these animals 
comprehended under the name of worms, or entozoa, live con- 
stantly in a fluid, and never, or at least very rarely in the 
atmospheric air. This fluid may be either living, or at least 
constituting part of a living body. In this case, they are 
more peculiarly entitled to the appellation of intestinal worms, 
or entozoa; and, in fact, the great majority of the worms are 
intestinal. 
There is no tissue, nor any constituent parts of living 
bodies in which some of these worms have not been found. 
They are most frequently at the surface of some portion of 
the exterior envelope, which has re-entered, to form either 
the intestinal canal, the lungs, or organs of respiration, or the 
genito-urinary apparatus. But at other times they are found 
in the tissue itself of these parts, in the parenchyma, as in 
the brain, the vessels, the muscular system, &c. 
Moreover, there is scarcely any animal in which some of 
these intestinal worms have not been found, at least if we 
speak of all the classes of the vertebrata; for among the 
invertebrata, they seem to be more rare. But as they have 
been as yet so little sought for in these latter tribes, it is im- 
possible to assure ourselves that they are so few as has been 
generally asserted and believed. 
It has been remarked that no intestinal worms have as yet 
