41 
l[ymenolepis^ was found to )>e infected after a month, during which 
time he was accustomed to collect the feces of an infected patient for 
use in Grassi’s experiments. As Grassi stated, however, these two 
cases are not conclusive, since the experiments were made in a countiy 
where the parasite is common, and since, also, the worms might have 
l)een present in the intestine without eggs being manifest in the 
feces. As further evidence of the occurrence of a development in 
man similar to that wliich occurs in the rat, Grassi (Grassi & Rovelli, 
1892a) mentions cases occurring during th(‘ years 1890 and 1891 in 
children of well-to-do families. Some of the children belonging to 
these families would l)ecom(' infected, and. 2 to 4 months later, their 
66 67 
Fig. 66. — Longitudinal section of an embryo of H. nana at about the same stage as the preceding 
figure; rostellum protracted: !>/. j>., anterior opening of secondary cavity; caud., caudal appendage; 
pr. car., primary cavity; m'. car., se(‘ondary cavity. Enlarged. (After Grassi <fc Rovelli, 1892a, pi. .3, 
tig. 24.) 
Fig. 67. — Longitudinal section of an intestinal villus of the rat, containing a cercocystis of If. nava. 
Enlarged. (After Grassi A Rovelli, 1892a. pi. 3, fig 2.5.) 
brothers and sisters would also show infection. In such cases it seemed 
to Grassi that the chances are very much against the possible swal- 
lowing of invertebrates which might contain cysticercoids, and that 
the circumstances are arguments in favor of the occurrence of direct 
infection, through the feces, from one child to another. Somewhat 
similar evidence is given by Venuti (1895), who, according to Massari 
(1898), was able to explain the phenomena associated with the appear- 
ance of Ilymenolepis among the inmates of a bo}^s' asylum at Catania 
onty upon the assumption that direct infection occurred. (See p. 55.) 
In the absence of conclusive positive experimental evidence, one 
ma}^ not, of course, mak^ the absolute statement that Ilyjnenolepi^ nana 
