238 APPLIED BACTEEIOLOGY 



from a pure culture, and is therefore probably due to 

 other organisms. 



The bacillus is the exciting cause in surgical gangrene, 

 and is pathogenic for horses, pigs, sheep, rats, mice, and 

 some birds, while cattle are immune. 



The result of an injection into an animal is to some 

 extent dependent on the size of the dose, and the larger 

 animals often recover. When this is so, they are said to 

 possess a subsequent immunity, which may also, according 

 to Eoux and Chamberlan, be induced by the injection of 

 filtered cultures, or of serum from animals that have died 

 of the disease. 



BUBONIC PLAGUE, 



Discovery and morphology of organism — Method of staining — Growth 

 on media — Distribution and occurrence of disease — Filth disease — 

 Pathogenesis — Characters and types of disease — Methods of con- 

 veyance — Antitoxin treatment — Serum treatment of Yersin — Protec- 

 tive treatment of Haffkine — Preventive measures — Conditions 

 favouring occurrence of disease — Steps to be taken to prevent and 

 retard progress of disease. 



The bacillus of Bubonic or Oriental Plague was discovered 

 independently by Yersin and Kitasato, when investigating 

 the character of the disease during the epidemic at Hong 

 Kong in 1894. The plague bacillus presents very few 

 special biological features ; it might be best described 

 as a cocco-bacillus. In the animal body it occurs as a 

 short, almost ovoid rod, generally linked in pairs, measuring 

 on the average about 2'3 yu, by 1"7 /u. ; but longer forms are 

 to be seen, measuring as much as 5 /tt. In cultivation the 

 young bacilli are so short as to be almost coccoid or 

 slightly oval, but in older cultures rod, thread, and 

 involution forms occur. In broth-culture the organism 

 forms chains appearing like a streptococcus. The organism 



