240 



definite conclusions, and as has already been stated, the parasites disap- 

 peared from the blood of rat number 11 a few minutes after its with- 

 drawal. As the examination of the blood of all the other infected animals 

 on hand on this date showed none containing parasites in a satisfactory 

 condition for the performance of the agglutination or bacteriolytic test, 

 these reactions could not be performed satisfactorily. 



SERIES NO. III. 



Experiments with Die African spiroclucla. — Mice numbered 1 and 2 had been 

 infected about one month before with the African spirochseta. A blood examina- 

 tion on November 8 showed no parasites to be present. The animals were bled to 

 death and the serum separated. 



Mice numbered 3 and 4 were infected with the African spirochseta on Novem- 

 ber 5. A blood examination on November 8 showed the parasites to be very 

 numerous. The animals were bled and a small quantity of the blood mixed with 

 citrate solution for agglutination reactions. The serum was separated from the 

 remainder. 



Experiments with the American spirochwta. — Mice numbered 5, 6 and 7 had 

 been infected about one month before with the American spirochaeta. A blood 

 examination on November 8 showed no parasites. The animals were bled to death 

 and the serum separated. 



Mice numbered 8 and 9 were infected with American spirochetal on November 

 5. A blood examination on November 8 showed a fair number of parasites present. 

 The animals were bled to death and a small quantity of the blood mixed with 

 citrate solution for agglutinative reactions. The serum was separated from 

 the remainder. 



The following agglutination reactions were performed: 



Conditions of reaction. 



Agglutination. 



Serum of— 



Plus citrated blood of — 



1-5. 



1-10. 



Mice 1 and 2 (im- 



Mice 3 and 4 (infected 



Marked after 15 minutes. 



Marked after 



mune to African &'). 



with African .S'). 





15 minutes. 



Mice 1 and 2 (im- 



Mice S and 9 (infected 



No agglutination but too few parasites pre- 



mune to African S). 



with American S). 



sent for a decisive test. 



Mice 5, 6, 7 (immune 



Mice 3 and 4 (infected 



Negative after 15 minutes; [ Practically no , 



to American S) . 



with African S). 



after one-half hour mod- ag-glutina- 

 erate agglutination. | tion. 



Mice 5, 6, 7 (immune 



Mice 8 and 9 (infected 



Parasites too scanty to judge definitely of 



to American S). 



with American S). 



reaction, few found scattered. Not agglu- 

 tinated. 



The following precipitin reactions were performed with the same sera : 



Conditions of reaction. 



| 

 Precipitin 

 reaction 



after 3 



hours. 



Sera of— Plus sera of— 



Mice 1 and 2 (immune to African S) 



Mice 1 and 2 (immune to African S) 



Mice 5, 6, 7 (immune to American S)__J 

 Mice 5, 6. 7 (immune to American S) 



Mice 3 and 4 (infected with African S) __ 

 Mice 8 and 9 (infected with American S)- 

 do__ 



Negative. 

 Do. 

 Do. 

 Do. 



Mice 3 and 4 (infected with African S) -_ 



