i6o 



Scientific Proceedings (84). 



The combination of attenuated serum in bone marrow and 

 desiccated brain also did not prove protective. Chickens No. 54 

 and No. 55 died after inoculation with virulent brain Q. Also 

 a combination of attenuated serum and attenuated brain in a 

 plasma medium proved to be a failure (Chicken No. 24) just as 

 well as the combination of attenuated serum and desiccated brain 

 (Chicken No. 73). But in many cases the incubation periods 

 were prolonged. This caused me to believe that in some of my 

 animals I had raised the resisting power, as Chickens II, 15, 65, 

 and 67 proved which resisted so many treatments. (Compare 

 Table I and Table II.) Before Chickens II, 15, and 67 under- 

 went their final test, I applied sera of these more resistent chickens 

 to all animals which were left and some of which had not been 

 treated so frequently with attenuated material. Then I raised 

 the resistance again by the following careful treatment. Chickens 

 30. 31. 3 2 > 33. 40, 57. 65, 70, 80, 81, 84, 86, 87, 88, 89, 

 90, 91, 96, 97, 98, 99, and 100 were now treated successively 

 between the 3d and 29th of November, with virulent brain, 

 virulent liver, and virulent serum, which had been allowed to 

 grow with embryonic chicken tissues in a plasma medium. When 

 after these new protective treatments all the chickens were again 

 tested, brain Q being inoculated in all of them, only chickens 57, 

 84, and 88, died, together with control animal A 2 . Brain Q killed 

 a normal untreated chicken, after it had been nine months in 

 glycerine, in three to five days. This is not a very virulent brain. 

 But having attained immunization of 22 chickens against a not 

 too virulent brain, the possibility of immunization against a highly 

 virulent brain was given. But at first I made a mistake and took 

 the highly virulent brain No. 15 which had been only one month 

 in glycerine, and applied serum No. 65 and brain No. 15 to 

 chicken No. 100 and lost it by this too severe treatment. There- 

 fore I used at first for the rest of the chickens the less virulent 

 brain No. 21. I prepared them by an inoculation with serum No. 

 65 and brain No. 21 (which had been in glycerine nine months and 

 killed a normal chicken in between three and four days) to all of 

 them together with a control animal No. K 2 . This control animal 

 died together with 86, 87 and 98. I waited now several weeks 

 for the final test. Then all the chickens underwent a renewed 



