23,5 Leach et al.: Hookworm Infestation 505 



In the case of Trichuris, however, only 19 per cent of the total 

 number of worms recovered were passed the first day, but the 

 percentage had risen to 84.5 the second day. Subjects who 

 passed no Trichuris after the first day numbered only three, and 

 fifteen passed none after the second day. Five subjects yielded 

 Trichuris on the third day. 



This makes it clear that the drug is not devoid of efficiency 

 against both species. The apparent delay in the reaction of the 

 drug against Trichuris is interesting, and it is not unlikely that 

 it is slightly more efficient than our figures show. It must be 

 borne in mind that Trichuris implants itself much more firmly in 

 the intestinal wall than do any of the other species of nematodes 

 and, while many of the worms may be killed by treatment, their 

 appearance in the faeces may be delayed until maceration pro- 

 gresses to the point where they break off along the course of the 

 relatively thin "neck," at or near the point of penetration into 

 the mucosa. It seems to us more likely that this furnishes the 

 explanation for this phenomenon rather than a supposedly cumu- 

 lative effect of the drug itself. 



OCCUPATIONAL DISTRIBUTION OF WORM COUNTS 



Though this phase of the hookworm problem is outside of the 

 scope of this paper, it seems not inappropriate to record the 

 distribution of worm counts with relation to the occupations of 

 the several men. Summarizing the worm counts for the entire 

 series, it is seen that 3,539 hookworms were recovered after 

 treatment. Of this number, 2,929 were Necator americanus and 

 610 Ancylostoma duodenale. The men, as has been said, were 

 drawn from widely separated portions of the Archipelago and 

 to a certain degree may be said to be fairly representative of 

 the Philippine Islands as a group. This yields a rather high 

 ancylostoma index, 17.2, thus fulfilling the prediction of Haugh- 

 wout(4) that Necator americanus probably would be shown to 

 be the dominant species in the Philippines, but that the ancy- 

 lostome index might be fairly high. 



By far the greater number of our subjects were registered 

 on the prison records as laborers, but there is reason to doubt 

 that the records regarding occupation as given to the prison 

 authorities were in all instances correct. For instance, we found 

 that a chief of police from Cebu Province harbored 154 worms, 

 while a "merchant" from Sorsogon yielded 355. We are in- 

 clined to believe that the chief of police either did not wear 

 his full equipment at all times or that he was engaged in some 



