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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 examined them 

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

 that both the slug and earthworm contained parasites in abund- 

 ance. None were found in Oniscus. To determine which one, 

 if any of these, was the host, I procured some 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 corn meal mixed with 

 pure water. 



EXPERIMENTS IN FEEDING EARTHWORMS. 



Exp. 1. On September 29, 1883, at 8.30 a. m., a 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 remove 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 

 remainder were in the oesophagus, 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 9th, at 8 a. m., another chick, a little over 

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



