102 Dr. Drummond on the Equivocal 
alvine excretions, and therefore the circumstance of a speci- 
men being found in water inhabited by fish of any kind may 
amount only to this, that it had originally belonged to the fish. 
Thus the celebrated Muller, when travelling on the borders 
of Sweden, was told of a rivulet in which Tzenize were to be 
found ; he visited it accordingly, and satisfied himself that the 
account was true, by taking out of its water bundles of dead 
Tape-worms coiled together. But what then? Did he find any- 
thing more? Yes, he found quantities of the intestines of fish 
which had been thrown in by the fishermen, which fairly ac- 
counted for the presence of the worms. (Rud. i. 373*.) No 
one who has been in the practice of examining the intestines 
of fishes in pursuit of their living contents, will be surprised at 
this account, since the quantity of tape-worm sometimes 
found in them is often almost incredible. Thus in a salmon 
of eleven pounds weight, in July, 1838, I found a number of 
Bothriocephali, the longest of which was four feet ten inches, 
and their united lengths amounted to upwards of fifty-nine 
feet. In the common Cod their number is often very great, 
and in a middle-sized turbot I have found upwards of two 
hundred specimens of the Bothriocephalus punctatus, each 
measuring from ten to eighteen inches in length. 
It would be unnecessary to dwell longer on this subject, as 
I believe all Helminthologists, and all who have considered it, 
are fully agreed that the Hntozoa have their natural abode in 
the animal body alone, and that in any other situation they 
infallibly perish. But the more difficult question is, how do 
they get there? 
This query cannot at present be satisfactorily solved, for 
the truth is that we know nothing of their origin; but I am 
not inclined therefore to suppose them to be the entities of 
equivocal generation, a doctrine still indulged in by natural- 
ists and physiologists of high name and authority, and which 
formerly was generally embraced with regard to all animals 
occupying the lower links in the great chain of animated 
being. 
But as the light of science burned bright, innumerable 
errors were by slow degrees seen into, and have long since 
ceased to blot the page of truth. They arose out of ignorance ; 
and to asimilar origin we are, I believe, to attribute the theory 
of equivocal generation, whether it be applied to a fungus, 
* Ata place about a quarter of a mile beyond Belfast Bridge, on Bally- 
macarret Strand, where worn-out horses are slaughtered, I have more than 
once seen dead ‘Teniz in a pool of water, but there could be no doubt that 
their original habitat had been the intestines of the slaughtered animals, 
dragged to the said pool by dogs, or kicked into it by idle boys.—J. L. D. 
