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duced, but think such a case must be very rare, and would be 

 unlikely to occur unless the embryos were fully developed in 

 the egg before they were taken by the fowl. 



Exp. 12. Three young robins (Tardus migratorius), in the nest, 

 were fed several infected earthworms each, daily, for twelve days. 

 These earthworms were taken from the same place as those given 

 the chicks. No well marked symptoms of the gapes were 

 observed. Two of them were killed, and three or four gape 

 worms found in the trachea of each. A number were also found 

 in process of development in the lungs. These birds live almost 

 entirely on earthworms during a part of the year, and I wished 

 to know whether they would serve as a host for the parasite, and 

 thus be instrumental in spreading the disease. The trachea of 

 robins differs, in its size and anatomical structure, from that of 

 poultry, especially at its lower part, where the last ring dilates 

 and forms a second larynx. Syngami generally collect from the 

 lower part of the trachea to its middle, and the gapes is simply 

 the effort of the bird to obtain more air through this passage, 

 which is obstructed by these worms. It is evident, therefore, 

 that birds which have a larger trachea would harbor a greater 

 number of syngami without suffering from the gapes. We see 

 this is the case in chicks after they are several weeks old, for 

 syngami can often be seen in their windpipes by opening their 

 mouths and straightening out their necks. Several worms can 

 thus be seen in large chicks, with very little embarrassment to 

 respiration. It is also not improbable that, although the embryos 

 may penetrate the oesophagus, pass to the lungs and thence to the 

 trachea, the greater part may be coughed up and swallowed 

 before they are able to obtain a hold on its mucous membrane. 

 We know, from an examination of chicks, that very many of 

 them are thrown off in this way. 



Exp. 13. On July 4th, at 5 p. m., fed a chick, about four weeks 

 old, a large number of syngami, just hatched, by turning the 

 water containing them down its throat. On July 11th, at 7 p. m., 

 this chick commenced to have the cough or sneeze characteristic 

 of the gapes. July 12th; coughed much more. On July 13th, 



