PARASITES OP 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 u 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 bookless tape-worm of 



Figure 55. Measles in veal,"reduced. Hearth and Home, after Cobbold. 

 Figure 56. One of the measles magnified. Hearth and Home, after Cobbold* 



