CESTOID WORMS. I15 

make a second migration: this time falling into the abdominal 
cavity, or becoming re-encysted beneath the outer capsule of the 
liver, or under the peritoneum, beneath the spine. This wandering 
occurs from about the sixth to the eighth week, and by the ninth 
week they are all re-encysted and may be found in most wild 
rabbits. Further experiments shew that if a dog be fed with the 
larvee in the wandering condition, they will not develop up into 
Teenie ; they must first have arrived at the stage of mature cys- 
ticerci; and further still, if more than a month elapses after 
arriving at maturity, they degenerate into a cheesy substance and 
loose the property of further development, even if transferred to 
the stomach of the dog. When, however, a dog eats a portion of 
rabbit in which is a mature and not degenerated cysticercus, the 
changes which follow are found to occur in the following order and 
time, viz. :—In from three to six hours afterwards the cysts and 
caudal vesicles are digested. In twenty-four hours only traces of 
cysts and caudal vesicles remain. ‘ 
On the 3rd day the Teenia is ¥% inch long. 
Seomy sigan : as 4 to 6 inches long. 
” 21st ”? ” 12 to 18 ry) ” 
ees Ou % 5 2/0f MmOrentectn aa. 
In 2 months és zt sexually mature. 
We may here note that the period which elapses between the 
voiding of the detached proglottis (or segment), and its death, is 
the only one in which the worm is without some host. The eggs 
retain vitality under most varying conditions ; they are dispersed 
by the wind, the feet of animals, &c., &c., and ultimately either in 
the act of eating or drinking. Some of them enter the body of a 
suitable intermediary bearer, and the cycle is again commenced. 
Some Teenie in the adult condition infest only a single species ; 
others extend to various animals of similar habits. The same may 
be said of the larval or cysticercal stage; some having a very 
limited range of intermediary bearers, as the larval Tenia 
cucumerina, which is only found in the louse. The Cysticercus 
cellulose usually found in the pig will also develop up in man; 
whilst the L£chinococcus veterinorum—the larval form of the 
Tanta Echinococcus has a very extended variety of bearers, having 
been found in the lion, antelope, sheep, ox, pig, monkey, kangaroo, 
the turkey, and in man: it is in the human bearer that it attains to 
its greatest development. 
In thus roughly sketching the life history of a tapeworm, I have 
incidentally drawn attention to the amount of disease and mortality 
they may occasion in the human subject. This is always in direct 
Proportion to the sanitary precautions adopted. In India, where 
the natives defoecate in the pastures and exposed places near 
villages, where cattle graze and eat the same, the Zenia 
