51 



that the larvae of some insect acted the part of host to the em- 

 bryonic form of Syngamus." Dr. Joseph Leidy believed the 

 embryos would be found in some intermediate host. The above 

 comprised our knowledge on this subject when this research 

 was begun. 



PRESENT INVESTIGATION, 

 The present investigation was commenced during the summer 

 of 1883. Great numbers of young poultry dying of the gapes, 

 some of my neighbors applied to me for aid to arrest the disease. 

 Knowing very little about the gapes, but having heard it was 

 caused by worms in the trachea, I made a careful examination 

 of their windpipes, and found numbers of the worms attached 

 thereto by their sucker-like mouths. Never having studied the 

 Entozoa, and having no works on them, I sent a specimen to Dr. 

 Joseph Leidy, of Philadelphia, asking him its name, and where 

 I would find information on the subject. He kindly replied, 

 and referred me to Dr. Cobbold on " Entozoa," and an article 

 by Dr. N. H. Paaren, in the American Entomologist, vol. 2, page 

 149. I immediately procured these, and reading the articles on 

 that subject, could find nothing regarding its origin. I there- 

 fore again addressed Dr. Leidy, asking him for the desired 

 information. On August 15th, 1883, I received his repl}^ as fol- 

 lows : "The source of the gape worm [Syngamus trachealis), of 

 chickens, has not been, discovered. If you have an opportunity 

 of investigating and determining its origin, you may do much 

 service to science. It would be found only in the embryonic or 

 larval condition, in some intermediate host." I thought this 

 was not only a good field for microscopic examination, but also 

 one which, should I succeed in the work, would be productive 

 of much good. Therefore, I commenced an investigation of the 

 coops and their vicinity, where the chicks suffered most 

 from the gapes. About these I found three not improb- 

 able sources of the disease : First, the common earth- 

 worm [Liimbricus terrestris) ; second, the sow bug [Ontsctis 

 asellus) ; third, the garden slug [Limax flavus). My at- 

 tention was especially directed to one coop, where the 



