ANIMAL PARASITES OF MAN. 193 



the individual was dismissed without further examination. Cases requir- 

 ing treatment were kept in the hospital and anthelmintics were admin- 

 istered repeatedly until two examinations for Ascaris or three for hook- 

 worms proved negative. The inadequacy of an examination based on a 

 single cover-glass preparation was fully recognized, and was repeatedly 

 proved by instances in which the first examination showed only one 

 infection Avhile subsequent ones revealed several. It is to be assumed 

 that since many individuals gave negative results at first and were not 

 again examined, many infections escaped diagnosis and that the figures 

 given are below the number of infections actually present in the 4,106 

 prisoners. 



A selection of cases presents itself because the prisoners were all 

 adults and nearly all males. The results of the work of a number of 

 authors, publishing in the aggregate upon about 10,000 cases, have 

 shown fairly conclusively that with the exception of a few species, the 

 percentage of infection with animal parasites is higher in children 

 than in adults, and in females than in males. Hence it would appear 

 in this connection also that the figures presented by the Bilibid pri- 

 soners are a minimum if taken as an index of infection in the popula- 

 tion as a, whole. 



Aside from the question of sex and age, it is probable that the pris- 

 oners at Bilibid are fairly representative of the general population, 

 coming as they do from the various provinces scattered throughout the 

 Islands and from all classes of society, although the lower laboring class 

 may have been present somewhat in excess of the proportion which it 

 holds in the mass of the people. 



The institution of this investigation and the recording and compilation 

 of the data obtained for this study were entirely the work of the author. 

 About 7,000 of the 15,000 examinations entering into this work were 

 made by Dr. Ralph T. Edwards, who was in charge of the Bureau of 

 Science routine work in clinical microscopy at Bilibid. Frequently 

 prisoners were examined and treated by Dr. E. C. Shattuck, 3 resident 

 physician at Bilibid, before the examination by the Bureau of Science 

 was made, and in order that our record of infections for each patient 

 might be complete, Dr. Shattuck has kindly allowed me to use the results 



3 Shattuck, Amer. Med. (1907) 13, reporting upon uncinariasis in Bilibid 

 Prison, particularly with regard to its diagnosis' and treatment, states that as 

 the result of approximately 1,000 examinations he found 243 cases of uncinariasis, 

 63 of amoebic dysentery, 3 of Balantidium coli infection, 186 of ascariasis and 7 

 of tseniasis. Shattuck's work was done from a clinical rather than statistical 

 viewpoint, and he has kindly given us his cooperation in our effort to establish 

 the actual frequency with which infection with animal parasites prevails among 

 the Filipinos. 



