OXYURIS VERMICULARIS 339 



Oxyuris vermicularis has been known since a remote period, and is one 

 of the most frequent and widely-spread parasites of man. It occurs 

 principally in children, and lives in the large intestine. 1 The females are 

 apt, in the evening, when the patients retire to bed, to leave per anum, 

 causing troublesome itching, and to wander between the nates and peri- 

 naeum, from whence, in girls, they occasionally reach the vagina. 2 Large 

 numbers may occasionally be harboured without inconvenience ; in other 

 cases various reflex symptoms are set up even in adults, which may rise 

 to epileptiform attacks. Occasionally the oxyuris are evacuated by the 

 mouth ; it is only very rarely that they reach the urinary bladder. 



Development. The eggs, which often adhere together, contain a 

 tadpole-like embryo, the thin tail of which is bent upwards 

 ventrally ; the embryo in a short time, given a sufficiently high 

 temperature, passes into a second embryonal stage, a folded nema- 

 tode shape, lying in the egg-shell, either in the faeces, with which also 

 numerous females pass out, or in the moisture of the groove 

 between the buttocks, and they there await the opportunity of 

 being reintroduced into man per os. It is very improbable that the 

 settlement may also take place direct in the large intestine, as is 

 occasionally stated, because although the harbourers of oxyuris are 

 frequently liable to auto-infection, this takes place through the mouth, 

 and is conveyed by the fingers, on which the ova of oxyuris, and 

 occasionally the female worms have clung. 



The opportunity for this is afforded every evening, as naturally the 

 troublesome itching caused by the travels of Oxyuris vermicularis is met 

 by scratching and rubbing with the fingers. It is, therefore, possible that 

 the eggs may even thus be introduced into the nose, where the young oxyuris 

 are perhaps hatched out, if they get high enough up on the moist pituitary 

 mucous membrane. As a matter of fact the larvae of oxyuris have been 

 found in the nose. Moreover, it may be understood that the eggs of Oxyuris 

 are transferred from person to person by the hand, directly or indirectly. 

 This again explains the wholesale infections which occur in collective 

 dwellings, after a person harbouring oxyuris has been admitted into 

 boarding houses, &c. The primary infection may be also caused in other 



ways by foods, fruits, vegetables and other articles that are eaten raw, and 



are polluted with the ova of oxyuris. Perhaps also flies or their excrement 



1 It has recently been stated that the lower part of the intestine is the original 

 seat of the Oxyuris ; in this situation it grows and copulation takes place, after which 

 the males die off, this explaining why they are so rarely met with in the excrement. 

 It is only after the eggs have developed" that the females wander into the large 

 intestine and reach the outer world. According to another statement, the vermiform 

 appendix is said to be the normal abode of Oxyuris in children. 



2 Simons removed a specimen from the cervical canal of the uterus (Ctrlbl. /. GynakoL 

 1899, p. 26 ; C. f. B., P. u. I. [i], xxvi., p. 235). 



