33 The Philippine Journal of Science 1923 



layers on the surface of the fluid medium, where they remain 

 floating like frog spawn. The gluey invisible substance that 

 holds the eggs together does not deteriorate after prolonged 

 exposure to air. In view of this gluey investment, the eggs 

 adhere tenaciously to any object with which they come in contact. 

 If the vessel, containing eggs on the surface of a liquid medium, 

 is tilted the eggs adhere to its sides and cannot be washed off 

 or pried loose by violent agitation of the contents of the vessel. 

 When sucked up in a glass pipette or stirred with a glass rod 

 the eggs adhere to the surface of the 

 glass with equal tenacity. In liquid 

 media normally oviposited eggs float, 

 and only isolated eggs sink to the bottom. 

 Following the discharge of eggs from 

 the uterus, the females of Oxyuris equi 

 shrink in size, the cuticle becomes 

 wrinkled in consequence of the shrink- 

 age, and the worms exhibit no further 

 signs of vitality. Egg laying thus 

 appears to be the last function per- 

 formed by the females of Oxyuris equi, 

 death probably ensuing after the act of 

 oviposition has been completed. Al- 

 though this conclusion is based upon 

 observations in vitro, it is highly prob- 

 able that the same course of events 

 ensues under conditions that are normal 

 for this parasite, because adult females 

 of Oxyuris equi are always full of eggs, 

 t 6 y P ?) X3W w- e tauld'T^ ff ait 8 indicatin £ that tne y discharge their eggs 

 Natural size. a all at once ; possibly they may oviposit 



several times in rapid succession, and 

 those that have discharged their eggs may be rapidly eliminated 

 from the digestive tract. The scarcity or even total absence of 

 males in hosts harboring numerous females of Oxyuris equi 

 warrants the view that the discharge of the sexual elements is 

 the final function in the life of the males, the latter probably 

 passing out of the host shortly after copulation. 



Numerous attempts were made to induce the discharge of 

 eggs by short-tailed females, but these attempts were only par- 

 tially successful, resulting either in the liberation of few eggs 

 or in a sudden eversion of the uteri and liberation of the eggs 

 with explosive violence. This occurred in water and in phy- 



