31 



Egg- Lay ing. 



As explained before, impregnation generally takes place 

 in the small intestine, or in the co3cum. The male then dies, 

 while the female remains for some time in situ, and she may 

 deposit some, or all, of her eggs within the bowel. If that 

 occurs, the ova are passed per rectum, and, as already shown, 

 must be swallowed in order to develop another generation. 

 Even if deposited the eggs are never hatched in the large 

 intestine or rectum, as is clearly proved by the fact that young 

 oxyurides are never found in that situation. Not unfrequently 

 the impregnated female herself, with her ova, is passed in the 

 stools, or she may wriggle out of the anus of her own accord. 

 She then deposits her eggs in some spot, from which they may 

 ultimately be transferred to a human stomach. In many 

 cases she may be even swallowed herself, alive or dead, by 

 an unsuspecting person, when her eggs are set free in the 

 stomach. 



Life Duration of Worm. 



The number of eggs deposited by one female has been 

 estimated at 10,000 to 12,000, and the life time of a single 

 generation of oxyurides is calculated to be from five to seven 

 weeks. At the end of this period, if no further infection should 

 have taken place in the meantime, the worms die out, with 

 or without medication, and the sufferer is spontaneously 

 relieved of the trouble. But this is a rare occurrence, unless 

 strict hygienic measures have been enforced, and re-infection 

 is apparently the rule, at all events amongst children, in 

 whom it is difficult, if not impossible, to ensure absolute 

 cleanliness. 



50 years ago, held the field, sug- II semble done fuir la lumiere, 



gested that Oxyuris was a nocturnal comme Duges 1'avait remarque." 



animal : " Le soir, il est a la (FiEVET, J. C., Qudques mots sur 



partie inferieure du rectum ; pend- Iss helminthes de Vhomme, Paris, 



ant le jour, a sa partie superieure. 1855/p. 16.) 



