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 lumbricoides (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 
