MANUFACTURE OF VACCINES 573 



combinations of killed bacteria are being constantly added to the 

 list of experimental products. Some of these have been under ob- 

 servation for a considerable time and are recognized as possessing 

 valuable properties. 



Typhoid Fever. — The typhoid bacterial vaccine of Wright* is 

 generally accepted as a valuable preventive against infection. For 

 prophylactic treatment, a series of three hypodermic injections 

 (500,000,000, 1,000,000,000 and 1,000,000,000) of killed typhoid 

 organisms are usually given. 



The curative value of typhoid bacterial vaccine has not yet been 

 determined. 



Canine Distemper. — Ferry,t corroborated by TorreyJ and Mc- 

 Gowan§ found this disease to be primarily an infection of the upper 

 respiratory tract due to a small motile bacillus, B. bronchisepticus. 



Ferry and Torrey proved that suspensions of killed cultures of this 

 organism will immunize dogs against experimental inoculations as well 

 as against the ordinary street infection. The bacterial vaccine is being 

 used for prophylactic purposes in graduated doses of 200, 400 and 600 

 million bacteria per c.c, given at intervals of about five days. 



Asiatic Cholera. — Two methods of vaccination against this 

 disease have been proposed and statistics which relate to field tests 

 show positive results with 'both. The method of vaccination resulting 

 from the work of Haffkine** depends upon the use of cultures of the 

 spirillum of Asiatic cholera, attenuated by growth at temperatures 

 above the optimum. Vaccines of different strengths are used. KoUe*** 

 has proposed the use of heated (killed) cultures of the organism. 

 Strongtt has developed a vaccine for Asiatic cholera consisting of the 

 filtrates from suspensions of killed and living Msp. comma {Sp. cholera 

 asiatica). This vaccine is standardized in terms of immunity units, 

 one unit " equaling the amount of immune serum which will protect a 

 guinea-pig of 250 g. weight against the intraperitoneal inoculation of ten 

 times the fatal dose of living cholera organisms." 



Bubonic Plague. — Practically the same methods of procedure 



* Wright, Jour, of Hyg. 2, 1902, p. 38S- 



t Ferry, Am. Vet. Rev., 1910, Vol. 37, p. 499. Jour, of Infec. Dis., 1911, vol. 8, p. 399. 

 t Torrey, Jour, of Med. Research, 1913, Vol. 27, 291. 

 § McGowan, Jour, of Path, and Baot., 1911, Vol. IS, p. 372. 

 ** HafiEkine, Brit. Med. Jour., 189S, 2. pp. 727, 1509. 

 *** Kolle, Deut. med. Woch., 1897, 23. p. 4. 

 ft Strong, Am. Med., 1903, Vol. 6, p. 272. 

 Strong, Philip. Jour. Sci., 1907, Vol. 2. p. ISS- ' 



