500 THE BACTERIOPHAGE AND ITS BEHAVIOR 



Again on May 19 specimens were collected in Long Huu, as follows : 



First. From the buffalo which had furnished specimen No. 1 on 

 May 13. 



Second. From two buffaloes living in a stable where three had died 

 from May 7 to May 12. These specimens all gave a bacteriophage 

 moderately virulent (++) for the bacterium of barbone. 



The animals which resisted, therefore, showed in their intestine a 

 bacteriophage virulent for the pathogenic bacterium. 



The epizootic does not always remain localized in a village. At times 

 it spreads rapidly from village to village and within a few days will 

 extend over a very considerable territory. It is rarely possible to 

 determine the primary focus, so great is the speed with which it spreads. 

 The mortality then becomes considerable, the losses often amounting 

 to tens of thousands of animals, as has been observed many times in 

 China, in British India, and in the Dutch East Indies. Sometimes 

 even, as actually happened in Java, the buffalo, as a race, is practically 

 eliminated. 



In the first two weeks of June, 1920, the epizootic became general in 

 the Province of Bac Lieu and in certain parts of the adjacent provinces 

 (western Cochin-China) . It was possible to examine the blood of eleven 

 animals which died in widely scattered parts of the area invaded, and 

 in all the bacterium of barbone was found in considerable quantity.* 

 The epizootic died out during the first fortnight of July. It had per- 

 sisted for a month, killing a third of the animals in the district. 



The region of Thoi Binh was particularly affected, the loss amounting 

 to more than fifty per cent of the buffaloes in the locality. From July 

 8 to 13, at the time when the epizootic was disappearing (the last animal 

 to be affected died on July 12), twenty specimens of feces were collected. 

 These were taken from buffaloes which had resisted the infection and 

 which at no time showed any evidence of the typical symptoms of the 

 disease. All of the animals examined lived on the farms of the village 

 of Thoi Binh or in the neighboring hamlets within a radius of fifteen 

 kilometers. 



Tests for the virulence of the intestinal bacteriophage against the 

 bacterium of barbone gave the results shown in table 62. 



* Bacteriological diagnosis is easy, even if the only available material is some 

 blood or a fragment of an organ taken without any special precautions in the field, 

 as is usual in such countries. Even if the specimen is some days old it is onl}- 

 necessary to smear it over the shaved skin of a rabbit. If the bacterium of bar- 

 bone is present the animal will die within 24 hours, and the organism will be found 

 in pure culture in the blood, from which it may be readily isolated. This is also 

 the best method for detecting the bacterium in soil or in fecal material. 



