IAIM. WORMS. 203 



The segments or the ova having been ingested by a hog, the 6-hooked 

 embryo is liberated and becomes encysted in the muscles of the hog, as 

 an invaginated scolex. Pork containing this Cysticercus (Cysticercus 

 cellulosae) is known as measly pork. If one by chance should carry 

 the eggs 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. 



Hymenolepis nana. This is generally known as the dwarf tape 

 worm it is the smallest of the human tape-worms. It is from 1/4 of an 

 inch to 1/2 inch in length, and is less than 1/25 of an inch in breadth. 

 The genus Hymenolepis has lateral g. pores, all of which are on the 

 same side. The head has 4 suckers and a rostellum, which is usually 

 invaginated. The rostellum has 24 to 30 booklets encircling it. The 

 eggs of this species are quite characteristic, there being 2 distinct 

 membranes. The inner one has 2 distinct knobs, from which thread- 

 like filaments proceed. The eggs of the H. diminuta have a thicker, 

 striated outer membrane and there are no filaments. The eggs of the 

 Dipylidium caninum are similar, but are found in the faeces in aggre- 

 gations several eggs in a packet. The dwarf tape-worm has been 

 found to be the most common tape-worm in the United States. Dr. 

 Stiles found it in about 5% of children in a Washington orphanage. 

 It has been estimated that in certain parts of Italy 10% of the 

 children may be infected. The symptoms, especially nervous ones, 

 may be marked in this infection. Although very small, yet the 

 number of parasites may be very great, even more than 1000. A 

 form found in rats, which may be identical with H. nana, does not 

 require an intermediate host. The 6-hooked embryo bores into 

 the intestinal villus and there delveops a Cercocystis (larva of 

 small dimensions with but little fluid). When fully developed, it 



