61 
tlie same ward. This fact tits in very well with the assumption that a direct infec- 
tion occurs from one person to another, and is evidence similar to that hrought 
forward by Veniiti (see ]). 55). 
AN ALYSIS OF CASES AXJ> DISCI SSIOX OF SYMPT03IS. 
AGE AND SEX OF INDIVIDUALS AFFECTED. 
In the 106 cases of II. nana^ at least 60, and probably 70, of the 
individuals affected were males; SO ivere females, while in the reports 
of the remaining- 6 cases the sex is not indicated. Sixteen and prob- 
ably 18 were over '10 years of age, 1 at least being over 50; 81 were 
younger than 20 years; in 1 cases no reference ils made to age. 
Between 1 and 5 }^ears there were 9 cases; 5 and 10 years, 21 cases; 
10 and 15 years. 5 cases; 15 and 20 years, 5 cases; 11 other cases were 
reported simply as children. 
According to these tigures Ilijmentjlepix nana is much more common 
among children than among adults, and males are more often infected 
than females. Five to 10 years seems to be the age most frequently 
affected. The very large percentages of males and children may be 
due in some degree to the fact that in the more heavily infected 
regions investigations have been made more especial!}^ among chil- 
dren than among adults, and among males than among females. 
GENERA!. ENVIRONMENT AND SOCIAL POSITION OF INFECTED 
INDIVIDUALS. 
With regard to the social position and general environment of the 
individuals affected, it is to be noticed, in the first place, that 32 of the 
cases were in orphan asylums or poorhouses, 27 being in the as 3 duni 
at Catania, Sicih^; 3 in two asylums at ^lacon, Ga., and 2 in a poor- 
house at Tok}m, Japan; and 6 cases were in an insane asylum in the 
District of Columbia. Of the remaining cases, 6 or 8 may be said to 
belong among the well-to-do classes. Grassi, also (Grass! & Rovelli, 
1892a), as alreadi^ stated, refers to an indefinite number of cases which 
occurred among the children of well-to-do families. It is only certain 
that the patients in about 20 of the 62 cases remaining were poor, but 
it is probable, judging from various circumstances related in connec- 
tion with individual cases, that the majority were from the poorer 
classes. 
The conclusion does not, therefore, seem unjustified that the children 
of the poor are more liable to infection, and children gathered together 
in institutions seem especially likely to show a heavy percentage of 
infection; the worm, in fact, seems to be particularly common in 
orphan as^dums. Among adults, also, institutional life seems to favor 
infection (cases Nos. 101 to 106). 
