THE ANIMAL PARASITES OF MAN 



the development of the broad tapeworm, the growth of which is rapid. 

 In my experiments on human beings the average number of pro- 

 glottids formed per diem averaged thirty-one to thirty-two for five 

 weeks, with a length of 8 to 9 cm. According to Parona the eggs 



FIG. 207. Dibothriocephalus latus : development of egg. I, segmentation complete ; some 

 cells of the blastosphere have migrated through the yolk and have flattened to form c, the 

 yolk envelope ; others form a layer of flattened cells (e) forming the embryophore ; the 

 remaining cells (d) of the blastosphere form the hexacanth embryo. 2, embryophore (e) is 

 becoming thicker. 3, the ciliated embryo has been pressed out of the shell ; /, the operculum ; 

 ^, the yolk envelope remaining in the shell (s) ; y, the yolk consisting of separate cells. 4, 

 a free-swimming larva much swollen by the water. (After Benham and Schauinsland.) 



appear twenty-four days after man has been infected. Zschokke found 

 the average growth in the experimental infection of man between 5-2 

 and 8'2 cm. per diem, and the person experimented upon by Ijima 

 evacuated a piece of a Dibothriocephalus latus, 22-5 cm. in length, 

 only twenty-one days after the infection. 



