56 Blackleg. 



will resist a subsequent artificial or natural infection. The results of 

 these experiments are very favorable, but the operation requires great 

 care and skill, because, if some of the vaccine should locate in the 

 porous tissue of the neck, fatal blackleg will almost surely result 

 (Bloire). Intratracheal injection with fluid from the swellings is 

 subject to the same consideration as to the immunizing efiEect and the 

 danger. 



Poels used virulent cultures of blackleg bacilli for protective vac- 

 cination. As soon as the formation of spores has begun in the culture 

 small cotton pads are immersed and afterwards dried; at the time of 

 vaccination they are pushed under the skin of the tail where they 

 cause a violent, but harmless, inflammation. During the years 1904 to 

 1906, 21,329 calves from 2 to 10 months old were vaccinated in Hol- 

 land according to this method with an annual total loss of from 1.0 

 to 1.4% (Balavoine). 



2. Protective vaccination with attenuated pure culture. 



Kitasato found that fresh bouillon cultures more than 2 weeks old 

 or heated to 80 °C. for half an hour did not kill guinea pigs, but im- 

 munized them effectively. Kitt had a similar experience (1894) with 

 subcutaneous injections of 1 to 5 cc. of bouillon culture in sheep and 

 cattle, which, 6 weeks later, resisted a virulent infection. Owing to these 

 favorable experimental results the method was used in practice for a 

 time. (In Austria, out of 7,434 cattle vaccinated during the years 1894 

 to 1895, 8, or 0.11% died as a result of the vaccination and 93 or 1.25% 

 from spontaneous blackleg.) 



Leclainche & Vallee injected cattle subcutaneously with a 5 to 8 

 days old bouillon culture which had been heated at 70°C. for 2 hours, 

 whereafter the animals thus treated were subjected one week later to 

 a subcutaneous injection of 2.0 cc. of a very virulent culture without 

 any harmful effect. This single vaccination, however, has not been 

 kept up in practice, because out of 39 animals 4 died as a result of 

 the vaccination. Later the vaccination was performed in 2 acts, the 

 first with a culture heated for 3 hours to 75°C. and the second with 

 one heated to 68-70° C. The result this time was also unsatisfactory, 

 one animal dying after the first vaccination and six after the second. 



Of the vaccine prepared by the sero-therapevitic institute at Toulouse 0.5 ec. 

 is injected into calves less than 6 months old, and 1.0 ce. into older animals, under 

 the skin of the ear or the end of the tail. 



Detre recommends a liquid vaccine which he prepares by separating the 

 muscle fibers and albumin coagula from the spores and toxins in the Lyons vac- 

 cine, obtaining a liquid which contains the same active substances as the Lyons 

 vaccine. The spores and toxins attenuated through higher temperature at two 

 different degrees of exposure in a hypertonic solution of salt, are offered for sale in 

 the market, and the vaccine is said to prove its efficiency in practical experiments. 



3. Immunizing vsdth toxins. Roux succeeded in immunizing 

 guinea pigs against blackleg by repeated injections of 15-day old bouillon 

 culture heated to 115° C. or a filtrate of such culture, into the ab- 

 dominal cavity, and also by subcutaneous injection of a bacteria-free 

 filtrate of the juice of the swellings. Duenschmann obtained similar 

 results with only the filtrate of the juiee of the swellings from animals 

 that had died from spontaneous blackleg. Finally, Schattenfroh used 

 pure solutions of toxins from which the bacteria had been removed by 

 means of clearing powder, but with very unfavorable results, as 23 

 out of 306 vaccinated animals died from the effect of the poison, and 

 40 to 50 more became very sick. 



