466 METAMORPHOSES OF THE INTESTINAL WORMS. 
worm of a different species, the taenia cucumerina. The other 
dog, to which the cysticerci had been administered, contained 
three bundles of worms, which were regarded as the taenia 
serrata by M. Van Beneden and the majority of the other 
observers. The bundle which was furthest from the stomach, 
and which was considered as proceeding from the first ad- 
ministration of cysticerci) was composed of taeniae which had 
nearly arrived at the adult state ; the other two packets were 
less advanced, that nearest the stomach being the smallest, 
and regarded as produced from the cysticerci last administered. 
The same results were obtained from another similar experi- 
ment ; but as this had been going on for a much longer period 
(the first injection of cysticerci having taken place on the 18th 
December), the taeniae situated at the greatest distance from 
the stomach were not only larger than in the previous ex- 
periment, but had the generative organs well developed. In 
all these cases the number of taeniae found in the intestines 
was less than that of the cysticerci swallowed ; thus, the first 
dog had received thirty-two, and the second seventy of the 
cystic worms; but the former contained only seventeen, and 
the latter twenty-five taeniae. 
M. Van Beneden informed M. Milne-Edwards that he has 
repeated these experiments no less than thirteen times, and 
always with equally decisive results. Similar experiments 
have also been performed by Kiichenmeister, Von Siebold,* 
and Leuckart, and always with the same success. 
The objections raised by M. Valenciennes to the deduction 
drawn by M. Van Beneden and other authors, from the ob- 
servation of the above facts, namely that the cysticercus 
pisiformis of the rabbit is the larval form of the taenia serrata, 
of the dog, repose principally upon the question of the specific 
identity of the parasite produced by the administration of the 
cysticerci to the last-mentioned animal with the taenia serrata , 
a worm which is so common, that, M. Valenciennes states, it 
may almost be predicted with certainty, that on opening a 
dog of four months old and upwards, this parasite will be met 
with. Previous experiments had proved to M. Valenciennes 
that the administration of the cysticercus pisiformis to dogs 
“gives rise to a flattened riband, composed of numerous 
narrow articulations, and presenting at the first glance 
exactly the appearance of a taenioid worm, like the taenia 
serrata” M. Valenciennes 5 observations agree closely with 
those of Von Siebold; but he states that the taenioid worms 
produced from the cysticercus pisiformis in his experiments 
never possessed generative organs, and the articulations never 
* Annals, N. S„ No. 60, Dec. 1852, p. 431. 
