280 
Life-liistory of Moniezia 
allowed complete liberty also complicated the experiment. The reason for not 
adopting a control was simply that of expense. The chances of success were 
so doubtful that the sacrifice of more than one lamb seemed unwarranted. The 
present experiment was intended as a “sighting shot” merely; if it were to fur¬ 
nish a clue it could be repeated the following season under the strictest control. 
On August 9th, that is to say, nearly four months after the administration 
of the first dose, the lamb was slaughtered and the udder region and also the 
alimentary canal were taken away for examination. Microscopic examination 
showed nothing out of the ordinary, the lamb was fat and had thriven well; 
there were no signs of adult tapeworms in the gut. A number of preparations 
were made of the udder and small intestine and were carefully examined, but 
no larval stage was found. The result of the experiment was therefore negative, 
both as regards the possibility of direct infection and in respect of an inter¬ 
mediate stage in the same host as the adult worm. 
As already noted, it is of critical importance in connection with this 
supposed mode of infection through the intermediary of the ewe, to establish 
whether Moniezia infection may be contracted by the lambs after they have 
been weaned. If this is really proved to be the case, then the above experiment 
loses most of its raison d'etre, unless there is a dual method of infection, which 
seems most unlikely. I am not satisfied, however, that infection with species 
of Moniezia does occur after the lamb has been weaned. Certainly, I have 
neither obtained myself nor read any conclusive evidence on this point. 
All the worms collected from Newcastle sources belonged to the one species, 
M . expans a. 
SUMMARY. 
Lambs contract Moniezia infection either at or very soon after birth, since 
they have been observed to harbour adult worms at 2-3 months old and in 
one case, to pass proglottids at 4-6 weeks. 
The intermediate host, if such exists, must be frequent on the pasture in 
early spring, otherwise lambs would not be found to harbour adult tapeworms 
so regularly or in such numbers when slaughtered in early summer. In the 
small intestine of a lamb from 3-4 months old slaughtered at Aberystwyth, 
there occurred 75 individuals. 
The fact that lambs regularly harbour adult tapeworms before they are 
weaned suggests the possibility of their contracting the infection from the 
mother-ewes. No direct evidence in this direction has been obtained, however, 
and an attempt to produce a larval stage in the udder region of a ewe by 
feeding to it the eggs of a tapeworm proved abortive. 
Hitherto, all attempts to produce the adult tapeworms directly by feeding 
the eggs to sheep have failed; there is, however, the remote possibility that 
the eggs require to undergo some kind of maturation process outside the body 
of the sheep before they will develop. The fact that several species of Moniezia 
occur in the domestic sheep would seem to require an intermediate stage, 
which would occur in a corresponding number of intermediate-host species. 
