PLAGUE AND BACILLUS PESTIS 825 



introduced since then. The one most extensively used is that of 

 Haffkine, which consists of cultures grown in broth in shallow bottles 

 for six weeks at room temperature and shaken once a day. At the 

 end of this time they are sterilized at 65 for several hours. The 

 material then consists of degenerated organisms and extracts of 

 the organisms. Glycerinated broth cultures have been introduced, 

 but so far have had little practical application. The German Plague 

 Commission 27 in 1899 introduced the use of heated cultures to which 

 0.5 per cent carbolic acid had been added. Strong 28 believing that 

 attenuated living bacilli might be more efficient than dead cultures, 

 produced vaccines from a three years' old laboratory culture, sub- 

 sequently cultivated at temperatures above 41. These living cul- 

 tures after such treatment had lost their virulence for guinea-pigs 

 and monkeys almost completely. He vaccinated forty-two individ- 

 uals with these cultures without harm, and with resulting develop- 

 ment of specific antibodies. The method is probably quite efficient 

 but because of the possible danger involved in it, has not been 

 extensively employed. The so-called nucleo-protein vaccins of Lus- 

 tig and Galeotti, 29 that is, plague bacilli extracted with weak alkalin 

 solutions and precipitated with acid in the cold, have been studied 

 extensively by Rowland 30 and others, and Rowland made several 

 vaccines of his own in one of which he extracted the bacterial mass 

 with sodium sulphate. He also used cultures killed with chloroform. 

 None of these vaccines have had any extensive application except 

 that of Haffkine which has been used by the British Government 

 Sanitary organization in India on a very large scale. Bannermann, 

 Bitter and more recently, Major Glen Listen 31 have analyzed the 

 results obtained with Haffkine 's virus of which over eight million 

 doses were distributed in India between 1886 and 1899. According 

 to these studies the Haffkine virus seems to be of definite prophy- 

 lactic value, though not completely protective as one would expect 

 from the nature and virulence of the disease. Major Listen states 

 in his report of the Bombay Bacteriological Laboratory for the years 

 1913 to 1916, that it is quite impossible to give any positive state- 

 ment for India, but that in isolated epidemics in which careful figures 



"German Plague Commission Report, 1899. 



** Strong, Philip. Jour. Science., Sec. B, 1907 and 1912. 



*Lustig and Galeotti, Deut. med. Woch., 1897-1912. 



80 Rowland, Journal of Hygiene, 1910-1914. 



"Liston, Maj. Glen, Bombay Bacter. Lab. Rep., 1913-1916. 



