35 



Irst Series of experiments: 



Four rabbits of approximatively the 

 same weight were inoculated with 10 cc. 

 of normal horse serum and bled on the 

 '4th, 5th, 9th and 16th day after inocula- 

 tion. The sera, after having been separa- 

 ted, were titrated for their precipitating 

 ▼alue, not only by making use of dilutions 

 of the precipitinogen, but also by using 

 dilutions of the precipitating serum itself 

 in the presence of a dilution of precipi- 

 tinogen at 1 to 100. 



4th day serum precipitating up frf 

 1/1.000 and precipitated, diluted at 1/2. 



5th day serum precipitating up to 

 1/10.000 and precipitated, diluted at 1/2. 



9th day senun precipitating up to 

 1/10.000 and precipitated, diluted at 1/8. 



16th day senun precipitating up to 

 1/10.000 and precipitated, diluted at 1/32. 



The precipitating sera were used 

 unaltered in the proportion of 0,5 and 

 the precipitinogen in decreasing pro- 

 portions from one half down to 1/64. 



Irst Series: 16th day Precip. Ser. 0,5-j-0,5cc of 1/2, 1/4, 1/8, up to 1/64 4th day serum- 

 ring up to 1/64. 



2nd Series: loth day Precip. Ser. 0,5-(-0,5cc of 1/2, 1/4, 1/8, up to 1/64 5th day serum 



— ring up to 1/64. 



3rd Series: 16th day Precip. Ser. 0,5-f0,5cc of 1/2, 1/4, 1/8, up to 1/64 9th day serum 



— ring up to 1/32. 



4th Series: 9th day Precip. Ser. 0,5-|-0,5cc of 1/2, 1/4, 1/8, up to 1/64 4th day serum— 



ïing up to 1/16. 



5th Series. 9th day Precip. Ser. 0,5-f-0,5cc of 1/2, 1/4, 1/8, up to 1/64 5th day serum— 



dng up to 1/16. 



6th Series: 9th day Precip. Ser. 0,5-|-0.5cc of 1/2, 1/4, 1/8, up to 1/64 16th day serum 



— ring up to 1/2 d" 



7th Series: 5th day Precip. Ser. 0,5-|-0,5cc. of 1/2, 1/4, 1/0, up to 1/64 4th day serum 



— ring up to 1/2 9 



8th Series: 5th day Precip. Ser. 0,5-hO,5cc of 1/2, 1/4, 1/8, up to 1/64 9th day serum- 

 ring up to 1/4 c^ 



9th Series: 5th day Precip. Ser. 0,5-hP,5cc of 1/2, 1/4, 1/8, up to 1/64 16th day serum 



— ring up to 1/16 d 



lOth Series: 4th day Precip. Ser. 0,54-0,5cc of 1/2, 1/4, 1/8, up to 1/64 5th day serum- 

 ring up to 0. 



11th Series: 4th day Precip. Ser. 0,54-0,5cc of 1/2, 1/4, 1/8, up to 1/64 9th day serum- 

 ring up to 1/4 d 



12th Series: 4th day Precip. Ser. 0,5-|-0,5cc of 1/2, 1/4, 1/8, up to 1/64 16th day serum 



— ring up to 1/16 cf 



2nd Series of experiments. 



Three rabbits of approximately equal 

 weight were inoculated subcutaneously 

 ^ith 15 cc. of normal horse serum and 

 were bled on 4th, 10th and 16th days. 



16th day serum precipitating up to 

 1/10.000 and precipitated diluted at 1/32. 



10th day serum precipitating up to 

 1/10.000 and precipitated diluted at 1/16. 



4th day serum precipitating up to 

 (?) and did not precipitate when diluted. 



The 10th day serum was kept in the 

 refrigerator for more than six days befo- 

 re realising the following experiments: 



