40 



March 19. — Dead. 



Post-Mortem : The central part of the right lung was inflamed. This 

 lung contained two, small pneumonic spots. All other interior organs were 

 normal, the spleen containing but a few colon bacilli. The nasal cavities were 

 <filled up with a slimy, gray offensive secretion, which contained many cheesy 

 masses. The left infra-orbital cavity was full of a yellow, cheesy matter, 

 which was in direct contact with an extensive pseudo-membrane on the palate 

 and left side of the mouth cavity. 



Pigeon No. 13. Was inoculated with roup bacillus like pigeon No. 12. 

 The general condition was disturbed. Six days after the infection, the pigeon 

 was killed. 



Post-Mortem : Nares apparently normal. Under the tongue, 2 small 

 pseudo-membranes have formed. The submucous tissue contains a solid, 

 cheesy mass, about as large as a hazel nut. 



Pigeon No. 14. Was inoculated with a roup culture which had been 

 growing in bouillon for 4 weeks. 1-5 c.c. was injected into the conjunctiva 

 of the upper eye-lid and mouth. The general condition became disturbed. 

 The eye-lids became swollen, and a solid tumor formed in it. This tumor 

 began to get soft again after two months, and finally showed typical fluctu- 

 ation. Size of the tumor, about 2 cm. 2. Two and a half months after the 

 infection (14th of April), the pigeon was killed. 



Post-Mortem : The tumor in the eye was caused by an abscess. The 

 centre contained liquefied, putrid, gray pus. The walls were formed by a 

 solid cheesy matter, which again was surrounded by a pyogenous membrane. 



Pigeon No. 16. Was similar to pigeon No. 14. 



Pigeon No. 23. Was inoculated with a virulent roup culture. The gen- 

 eral condition was considerably disturbed. Small croupous membranes form- 

 ed on the mucous membrane in the mouth. Five days after the infection (14th 

 of April), a serous catarrh of the left nostril became apparent. Two days 

 later, the pigeon had a very offensive smell. These symptoms disappeared 

 after a few days, and the pigeon recovered. 



Resume or Inoculation Experiments. 



Reviewing our experiments with the 24 chickens, we see that to produce 

 a typical case of roup, it was necessary to use a freshly isolated roup bacillus 

 culture (fowl No. 3). Fowls 22 and 23 had been inoculated with the same 

 culture grown for some time on artificial media. This caused considerable 

 loss of virulence and failed to produce the disease. 



Fowls 13. 17 and iS were inoculated with young cultures from some of 

 the diseased parts of naturally infected fowls. These were not pure roup 

 cultures, and their effect upon the chickens was only a slight one. By pass- 

 age through pigeons, however, the roup bacillus was made more virulent. 

 The bacillus was usually isolated on agar or gelatine plate cultures. 



The fowls 26. 28-33 were infected with a culture passed through one pigeon. 

 These fowls had been suffering from natural roup in early winter, but at the 



