11 
transparent preparation which could be examined throughout the 
area of the cover glass was more satisfactory than the method advo- 
cated in the report of the Anaemia Commission in Porto Rico of 
simply compressing the undiluted feces by pressure upon the center 
of the cover glass, and thus obtaining a clear center for examination, 
but thick, opaque borders. 
Preliminary report. — In May, 1903, a report was published upon 
the results obtained up to that date. (A statistical study of the 
intestinal parasites of 500 white male patients at the United States 
Hospital for the Insane. By Philip E. Garrison, Brayton H. Ran- 
som, and Earl C: Stevenson. Bull. 13, Hyg. Lab., U. S. Pub. Health 
and Mar. Hosp. Serv., Mash., pp. 1-13.) These 500 cases are incor- 
porated in the present paper, which is, therefore, a full report of all 
cases examined during the two years of the investigation. 
Acknowledgments. — It is a pleasure to acknowledge the courtesy 
and cooperation of those in charge of the institutions upon which 
we have been dependent for material for our work. To Doctors 
Richardson, Mhite, and Stack, at the Government Hospital, and 
to Dr. Henry S. Noble, superintendent, and Dr. A. R. Diefendorf, 
pathologist, at the Connecticut Hospital, and also to the other mem- 
bers of the hospital staffs we are indebted for their interest in fur- 
nishing every facility for obtaining the specimens. It is only justice 
to mention in this connection the many nurses and attendants upon 
whom fell a large portion of what in some respects was the most dif- 
cult and most unpleasant part of the work. 
FREQUENCY OF INFECTION. 
Of the 3,457 persons examined, 349 were infected with intestinal 
worms, an average of 10.1 per cent. The parasites present were 
whipworms (Tin churls trichiura), pin worms ( Oxyuris vermicularis) , 
eelworms ( Ascaris lumhricoides), hookworms ( Uncinaria ( Necator ) 
americana and Agchylostoma duodenale a ), Cochin-China worms 
( Strongyloides stercoralis), the dwarf tapeworm ( Hymenolepis nana), 
and the fat tapeworm ( Tsenia saginata). 
Concurrent infections. — The presence of two or more species of 
parasites in one person was found 36 times among our cases, the dif- 
ferent forms occurring together as follows: Tnchuris and Ascaris , 4 
times; Tnchuris and Oxyuris, 6 times; Tnchuris and hookworms, 15 
times; Tnchuris and Hymenolepis , 5 times; Tnchuris and Strongy- 
loides, once; Tnchuris and Tsenia saginata, once; Oxyuris and Ascaris, 
a In the one case of hookworm disease in which we obtained the worms (autopsy) the par- 
asite was U. (f\ .) americana A ecator americanus ], and the large size of the eggs found in the 
other cases indicated that they also were infections with the American species. Most of 
the infections, however, were in men recently returned from the Philippine Islands, where 
the old world form (A. duodenale ) is supposed to be common. In view of the possible 
uncertainty as to the species present in all but the one case we use the general term hook- 
worm throughout for these infections. 
