9 



second, the sow bug (Oniscus ascllus); third, the garden slug 

 Limax Havus). My attention was especially directed to one coop 

 where the chicks all had the gapes. This was placed on a grassy 

 plot, but close by its side was a small space of bare ground, a 

 few inches square. It seemed quite probable that here was the 

 place where they obtained the parasite, so I dug into it and found 

 it full of earthworms. I took some of these home and exam- 

 ined them with the microscope, as I did also Oniscus and Limax. 

 I found that both the slug and earthworm contained various 

 kinds of parasites in abundance. None were found in Oniscus. 

 To determine which one, if any of these, was the intermediate 

 host of Syngamus trachcalis, I procured some young chicks from 

 a neighborhood where no gapes existed, and fed each separately 

 to the chicks. In neither of the chicks fed with sow bugs or 

 slugs was any result produced, but the chick fed with earth- 

 worms developed symptoms of the gapes. To guard against 

 error, all the chicks were kept in a barn where they had no access 

 to the ground, and their food was cornmeal mixed with pure 

 water. 



EXPERIMENTS IN FEEDING EARTHWORMS. 



Exp. i. On September 29th, 1883, at 8:30 a. m., a marked 

 chick, about one week old, was fed ten earthworms from the bare 

 spot of ground by the side of the coop where the chicks had 

 the gapes. The worms were carefully washed in water to re- 

 move all the dirt adhering to them, which might contain the 

 eggs or embryos of Syngamus. On October 6th, at 7:30 a. m., 

 six days and twenty-three hours after the feeding, I observed the 

 first symptoms of the gapes. On October 7th, at 10:30 a. m., 

 eight days and two hours after feeding the chick, and twenty- 

 seven hours after the first symptoms of the disease, I killed it and 

 found twenty-six gape worms. Of these worms, two only were 

 found in the trachea; they were at its upper part, and were the 

 largest. Ten or twelve of them were in the pharynx. The re- 

 mainder were in the esophagus, from its upper part half way 

 down to the crop. All these were united in pairs, except one 

 male and female. 



Exp. 2. On October gth, at 8 a. m., another chick, a little 

 over two weeks old, was fed four earthworms from the same 

 place, with like precautions. At the same time of day on the 

 10th it was fed six worms. On the nth, 12th, 13th, 14th and 



