502 The Philippine Journal of Science ms 



worm escapes into the lumen of the intestine. The ruptured 

 cysts are liable to become invaded by intestinal bacteria, which 

 may give rise to ulcerations, perforation of the intestine, and 

 peritonitis. 



Of the 3 human cases described, in Foy's (Leiper) case the 

 parasites were passed in the stools during treatment for hook- 

 worm, and there is no record of clinical symptoms or patholog- 

 ical conditions; in Brumpt's case, in which the infection was 

 discovered post mortem in a patient dead from other causes, 

 only 6 oesophagostomum nodules were found; in Thomas's case 

 there was an intense infection, and death of the patient was 

 from septic peritonitis due to lesions caused by these worms. 



Our knowledge of the life history of (Esophagostomum is ex- 

 tremely meager. Weinberg (1908) and Thomas (1910) infer 

 from their observations that the larva of the worm reaches the 

 wall of the intestine by the way of the blood where it ruptures 

 a small blood vessel and becomes encysted in the submucosa, 

 in the internal or external muscularis, or in the subperitoneal 

 space. Here the larva grows, molts, and becomes an immature 

 adult oesophagostomum. The cyst is then ruptured, and the 

 worm escapes into the lumen of the intestine. Weinberg found 

 free immature adults in the intestinal contents of a few of his 

 cases of infection in monkeys. However, no one has described 

 a mature adult, and the ova of the worm have never been found 

 in the lumen of the intestine.^ Moreover, no author has observed 

 or even speculated on how the larvae get into the blood or what 

 is the early larval life of the worm. Are the eggs laid in the 

 intestine of the host or after the worm has been passed in the 

 faeces? If laid in the intestine, do the eggs develop there or 

 outside of the host? If development takes place outside of the 

 host, is it only intra ovum or is there a free larval stage? And 

 if a free larval stage exists is it in the open or is an alternative 

 host required? 



Among the monkeys used for experimental purposes in the 

 biological laboratory of this Bureau, infection with oesophagos- 

 tomum occurs in a large percentage of the animals. Therefore, 

 unusual opportunity has been afforded for investigating the 

 life history of this worm. These monkeys are collected from 

 different parts of the Philippine Islands, and include at least two 



' Weinberg records in one case the presence of an adult female worm and 

 spherical eggs measuring 52 microns in a cyst from the caecum of a 

 chimpanzee; but in view of my own observations it is doubtful whether 

 the worm ever becomes mature in the cySt. 



