CARRIAGE OF DISEASE 173 



Parasitic Worms 



Nuttall and Jepson refer to the experiments made by 

 Grassi in 1883. When he broke up segments of the 

 human tapeworm in water after these had been pre- 

 served some months in alcohol, he saw that the flies 

 came and sucked up the eggs with the water and that 

 the eggs were passed unaltered through the bodies of 

 the flies. He had the same results with the eggs of Ox- 

 yuris, one of the so-called ''thread-worms" or ''pin- 

 worms." 



While experimenting with the unsegmented eggs of 

 still another of the genus Trichocephalus (one of the 

 so-called "whip worms," having a long, slender neck 

 like a whip lash), which were placed upon a table, he 

 saw flies feed on them and later found the eggs in the 

 fly-specks which had been deposited in the kitchen on 

 the floor beneath, ten yards away from the place where 

 the insects had been fed. He caught some flies whose 

 intestines were full of the eggs. 



Nuttall also records an observation of Dr. C. W. 

 Stiles, of the Public Health and Marine-Hospital Ser- 

 vice, which had been sent to him in a personal letter, 

 showing that Stiles had placed fly larvae with the fe- 

 male of Ascaris lumhricoides (the most abundant of 

 the "round worms," which inhabit the small intestine, 

 especially with children), which they devoured together 

 with her eggs. He afterwards found that the larvae 

 and the adult flies contained the eggs of the Ascaris. 

 The experiment was made in very hot weather. The 



