340 THE DEVELOPMENT OF CESTODES. 



tribution which I have established in the case of Trichina, one is in- 

 clined to suppose that in the above cases the wandering is through 

 the connective tissue substance, and that the embryos bore through 

 the intestinal wall into the body-cavity, in which they wander where 

 they will. I am inclined to support this theory, particularly in the 

 case of the common tape-worm of man, which presents in its occur- 

 rence and the distribution of its cystic forms close resemblances to 

 Trichina. 1 



When the six-hooked embryos have once reached their future 

 resting-place their further development begins. Originally percep- 

 tible only by help of the microscope, they increase so rapidly that 

 they are often in a few days visible to the naked eye. Further, 

 by their pressure on the infected organs, the growing worms cause a 

 proliferation of cells which, completely surrounding the worms, make 

 them look larger than they really are. These cells become in course 

 of time the coating of the cystic bladder, provided no change of posi- 

 tion occurs. 



In many cases this proliferation of cells is so marked that it has 

 been reckoned as the result of a decidedly inflammatory process. 

 Thus the Ccenuri, which wander into the lamb's brain (Fig. 181), sur- 

 round themselves with a thick, exuded sheath, which becomes drawn 

 out into long bands, in consequence of continued wandering (p. 135). 

 Similarly, in the rabbits infected 2 with T&nia serrata, the liver was, on 

 the fourth or fifth day after infection, seen to be studded with white 



FIG. 181. Brain of a lamb with passages of Ccenurus (natural size). 



points or knots, which were most deceptively like miliary tubercles, 

 but in two or three days after had grown to 0*5 mm., and were, 

 like the Coccidium-nodules (p. 207), surrounded by an envelope of 

 connective tissue. 3 The young bladder- worm lying inside is much 



1 Thus, according to Fiirstenberg, the embryos of Tcenia coenurus reach the brain 

 through the foramina, via the connective tissue. (Ann. d. Landwirthschaft in den Tcgl. 

 prcuss. Staaten, Jahrg. xxiii., pp. 43 and 166, 1865.) 



2 See " Blasenbandwurmer," p. 121, tab. 1, fig. 1. 



3 I ought to mention here that the growth and development of the bladder-worms are 

 by no means alike in all cases. Not only do the different organs infested induce numerous 



