8 
an uneven distribution might be -explained b the difference in the histories of the patients 
prior To admission, especially as patients of a similar history are often found congregated 
upon the same ward or in the same building. At the Connecticut Hospital the patients have 
a relatively uniform history, having been admitted from civil life and from the bounds of 
the one State. At the Connecticut Hospital 13 wards gave no infections: 29 wards varied 
from 2. So to 75 infections per 101 persons. The rate of infection in the four buddings 
varied from 5 infections per 101 persons in building A to 61.33 infections per 100 persons 
in bunding D: separating the male and the female sections in each b uilding , we have 7 
sections, among which the rate of infection varied from 2.56 to 61.33 per 100 persons. 
The same unequal distribution of infections among the different wards was found in the 
case of pinworms and of whipworms, considered separately. With regard to pin worms, 
this is naturally explainable by the direct t ransinissibility of the parasite from one person 
to another: hence we would rind a group of '-ases centered around one focus of infection. 
In the absence of direct transmissibility in the case of whipworms, we have analvzed the 
conditions of sex. age. length of hospital residence, and of nativity among trie patients upon 
the different wards with a mew to discovering such combination of these factors as would 
explain the widely varying amounts of infection. N combination was found which would 
give any adequate explanation. - - 
Reports on the examination of over 25 , 001 persons for intestinal worms in different parts 
of the world, published by over 30 different authors. I ring out the fact that the rate of infec- 
tion varies widely in different localities. 
Our statistics of the relative frequency of whipworms among whites and negroes in the 
District of Columbia, when compared with me statistics of the relative frequency of Typhoid 
in the two races in this District, are not in harmony with the theory that wjrpvorins p.av 
a role in typhoid fever. The point remains to be established, however, whether the pub- 
lished statistics as to the frequency of typhoid in the neg. o and in the white are not mis- 
leading. in view of the fact mat the published cethaity of typhoid is so much higher in 
the negro than it is in the white. 
INTRODUCTION. 
The present investigation was undertaken for the purpose of deter- 
mining the prevalence of intestinal worms in man in certain localities 
in the United States. Heretofore our ideas on this subject have been 
based chiefly upon the number of infections reported by general prac- 
titioners and by hospital clinicians in our own country, or drawn by 
analogy from the results of foreign investigations. Foreign results, 
however, are not necessarily applicable to this country: further, the 
conclusions founded upon the reports of physicians and hospitals are 
naturally inadequate when we consider that, as a rule, only the 
severer cases of infection are brought to the notice of the physician: 
furthermore, that usually only the most common worms are consid- 
ered by practitioners, and. finally, when we recognize the fact that as 
a rule microscopic examination of the feces, which in most instances 
is preeminently the best and in many cases the only certain method of 
diagnosing intestinal infections with a nim al parasites, has until 
within the last few years had little place in the practice of American 
physicians or even in American hospitals. 
Source or material. — The practical difficulties in the way of 
obtaining several thousand specimens of feces from the general popu- 
lation can be appreciated even by persons who have not had espe- 
