PARASITES OF ANIMALS. 75 
of their six boring hooks, through the intestine into the cir- 
culation and, lodging in the muscles, caused serious disease 
or death, if in too large numbers, and after a time became 
enclosed ‘in little capsules, producing, in fact, “measly” veal 
or beef, as shown in Figure 55, which represents part of a 
muscle of the hind leg from a calf that had been fed by Drs. 
Cobbold and Simonds upon the eggs of this tape-worm, and 
killed three months afterward. The flesh of this calf was 
estimated to contain over eight thousand measles, and yet, 
although at first it had been seriously ill from the effects of 
the parasites, it was at the time when slaughtered perfectly 
Figure 55. Figure 56. 
healthy and fat. The measles of veal or beef are much 
smaller than those of pork, and if they existed only in 
moderate numbers, would scarcely be detected either by the 
butchers or consumers. They are seldom larger than a small 
pea. One of these “measles,” when examined with the 
microscope, is found to consist of an outer oval cyst or mem- 
branous sac, enclosing loosely in its cavity a more delicate 
vesicle filled with fluid and containing the inverted head of - 
the young tape-worm, as represented in Figure 56. The head 
has four well-marked suckers, but has no central proboscis 
and no circle of hooks—differing therefore from the pork- 
measle, or cysticercus, in just the same way that the heads of 
the mature tape-worms differ from each other. Thus it was 
definitely settled that the unarmed or hookless tape-worm of 
Figure 55.—Measles in veal, reduced. Hearth and Home, after Cobbold. 
Figure 56.—One of the measles, Pagnificd.. ofdgarth and Home, after Cobbold, 
