BUREAU OF ANIMAL INDUSTRY. . 551 



ply a complete set of Ms microscopical preparations for study. We 

 have only space to give the more important parts of this work. Dr. 

 Walker, believing that the embryo of this parasite has an intermediate 

 host in some invertebrate, living on the infected grounds, came to the 

 conclusion that the earth-worm must be the animal in question. His 

 experiuieuts are quoted in the following pages : 



Experiment 1. — On September 29, 1883, at 8.30 a. m., a chick about one week old was 

 led ten earth-worms 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 s^n^am((s. On 

 October 6, at 7.30 a. m., six days and twenty-three hours after the feeding, I observed 

 the first symptoms of the gapes. On October 7, 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. 



Experiment 2.— On October 9, at 8 a. m., another chick a little over two weeks old,wa9 

 fed four earth-worms from the same place, with like precautions. At the same time of 

 day, on the 10th, it was fed six worms. Ou the 11th, 12th, 13th, 14th and 1.5th, it was 

 fed ten worms daily. At the same time from the first feeding, a little less than seven 

 days, it had the gapes. It was killed in eight days, and twelve gape-worms found, all 

 in the trachea. 



Experiment 3. — Commencing on November 13, three chicks, two days old, were fed 

 earth-worms from my garden, eight, nine, and ten days, respectively. No symptoms 

 of the gapes were produced, but to determine positively, the one fed nine days was 

 killed, and no gape- worms found. This experiment shows that all earth-worms do 

 not contain the embryos of syngamus. To confirm this, earth-worms from the same 

 place have been repeatedly examined with the microscope. 



Experiment 4. — Two mature sijngami were broken in pieces so as to free the eggs. 

 They were then placed on the surface of a dish filled with dirt, well moistened with 

 water. After two weeks, some earth-worms were placed in this dish and allowed to 

 to remain ten days. Three of these were fed to a chick, which was carefully watched 

 for two weeks. No symptoms of gapes were discovered. Evidently the embryos had 

 not obtained access to the earth-worms in suQiclent numbers to produce the disease 

 in chicks. 



Experiments b andd. — On December 13, two chicks, four weeks and four days old, 

 were each fed six earth-worms, from the infected spot, with the same precautions as 

 before. On the 15th, 16th, and 17th, the feeding of six worms was repeated, making 

 twenty-four to each chick. On December 20, about seven days as before, they had 

 the first symptoms of the gapes. One was killed and twenty-two syngami found. 

 On December 24, eleven days from the feeding, the other was killed and sixteen found. 

 All of them were united and in the trachea. None were found in the lungs, but it is 

 probable they were there, and want of experience in the search prevented their dis- 

 covery. 



Experiments 7, 8, and 9.— Ou April 21, 1884, fed three chicks two days old, each five 

 worms, from the same place where the others were obtained. Repeated the feeding 

 on April 22, 23, 24, 25, 26, and 27. Ou April 28, about seven days from the first feed- 

 ing, all had the gapes. One was killed and syngami found in the trachea, also three 

 pairs in tlie lower part of the left lung, and one pair in the lower part of the right 

 hiug. Continued to feed the two remaining chicks earth-worms, until May 5, just 

 two weeks from the first feeding, when one was killed and the lower part of the traciiea 

 found crowded with syngami. One of these measured seventh-eighths of an inch 

 in length, and two or three others three-fourths of an inch. They contained fully 

 developed eggs, as did also the excretions of the chick just before it was killed. Tliis 

 proves that the embryo of syngamus in the earth-worms is developed to maturity in 

 tAvo weeks from the time it obtains entrance to the chick. 



Experiment 10.— On July 16 fed a chick ten earth-worms, and repeated the feeding 

 for nine successive days. The gapes observed on the seventh day as usual. On July 

 ■Ji), ten days from the first feeding, I killed this chick and found a large nuniber of 

 xi/ngami in the trachea, and also the embryos in different stages of growth in the 

 lungs. 



Experiment 11. — In order to see if Dr. Megnin's theory was correct, that the eggs 

 would develop within the fowl, I fed a chick, about three weeks old, on July 2lt. tlneo 

 perfect S!/nj7ami, containing many thousands of eggs. This chick was carefully watched 

 for five weeks and no symptoms of gapes observed. 



Experiment 12. — Three young robins (Turdus migratorious) in the nest, fed several 

 infected earth-worms each daily for twelve days. These earth-worms were taken 

 from the same place as those fed the chicks. No well-marked symptoms of the gapes 

 %vere 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. 



