HYMENOLEPIS 307 



are introduced into the human stomach. Cooking meat always destroys the 

 cysticercus. A period of about two months elapses after the ingestion of the cysti- 

 cercus before the mature segments pass out of the rectum. These not only make 

 their exit with the faeces, but are also capable of wandering out at other times. In 

 this they differ from the segments of T. solium. T. saginata next to Hymenolepis 

 nana is the common tape-worm of the United States. Dr. Stiles has examined 

 several hundred tape-worms in the United States during the past few years and 

 has found only one T. solium. 



In Paris Blanchard found 1000 T. saginata to 21 T. solium. Certain 

 German statistics, however, show about one-half as many T. solium 

 as T. saginata. 



Abnormalities of the scolex and proglottides are not uncommon with T. saginata. 

 This is less frequently the case with T. solium. 



Taenia solium. The measly pork tape-worm is smaller than the 

 T. saginata and differs from it in having a globular head, with a ros- 

 tellum which is crowned by 26 to 28 booklets. 



In T. saginata a depression takes the place of the armed rostellum; the suckers 

 of T. saginata are, however, much more powerful than those of T. solium. The 

 segments have only five to ten coarse branches and are expelled only at the time of 

 defecation. The segments or the ova having been ingested by a hog, the six-hooked 

 embryo is liberated and becomes encysted chiefly in the tongue, neck, and shoulder 

 muscles of the hog, as an invaginated scolex. Pork containing this cysticercus 

 (Cysticercus celluloses) is known as measly pork. This cysticercus contains much 

 more fluid than that of the ox and is from % to ^ inch long. If one by 

 chance should carry the egg on his fingers to his mouth, as the result of examining 

 mature segments, the larval stage may be established in man. If this infection is 

 not heavy, very few symptoms may be observed. The cysticercus, however, tends 

 to invade the brain, next in frequency the eye, and so causes convulsions, death or 

 blindness. Instead of only being the size of a pea, these cysts, when forming in the 

 brain, may be the size of a walnut or larger. T. solium is comparatively common in 

 north Germany, but is exceedingly rare in England and the United States. 



Taenia africana. This is an unarmed tape-worm, only about 5 feet long. It 

 was found in a native soldier in German East Africa. 



Garrison has reported from the Philippines a tape-worm with an unarmed 

 rostellum, V-shape and spiral formation of the uterine stem with compact structure 

 of the gravid uterus under the name of Tania philippina. Another tape-worm, 

 T. confusa of which only segments were found was reported by Ward from Nebraska. 



Hymenolepis nana (Tsenia nana). This is generally known as the 

 dwarf tape- worm it is the smallest of the human tape-worms. It is 

 from Y inch to ^ inch in length, and is less than >^ 5 inch in breadth. 

 (10 X i mm.) 



