Studies in Bacterial Variability. 



59 



24 hours later in 250-c.c. flasks containing 100 c.c. of bouillon. The latter 

 were grown for 24 hours at 37° C, and then well shaken up and formolised. 

 They were placed in cold storage and shaken up several times a day 

 for 3 or 4 days, and were subsequently diluted with formolised normal 

 saline solution to standard opacity. Microscopic examination before 

 formolisation showed that T.e. 5 was almost entirely in the non-motile 

 phase, T.e. 9 short and very highly motile. Serums were prepared by 

 inoculating rabbits intravenously with 1 c.c. of these formolised cultures, 

 and taking blood on the eighth day. Eabbit 1 received 1 c.c. of culture T.e. 

 and serum was prepared (serum I, 1); a month later it received 1 c.c. of 

 culture, T.e. 5, yielding serum I, 2, and, after the lapse of a month more, it 

 received 1 c.c. of T.e. 9 and yielded serum I, 3. 



On the same day as the last of these inoculations, rabbits 2 and 3 received 

 intravenous inoculations of 1 c.c. of cultures T.e. 5 and T.e. 9 respectively, 

 and serums II and III were subsequently obtained from them by bleeding on 

 the usual day (eighth). 



These serums, together with a 100-unit standard serum (Dreyer), were then 

 tested out against the cultures T.e., T.e. 5 and T.e. 9, using the series of 

 dilutions 1 in 25, 50, ,125, 250, etc., of Dreyer's series, and recording the 

 results in Dreyer's notation of total (t), standard (s), trace (tr), and inter- 

 mediate values {e.g., s — , tr + ) as required. The tubes were read after 

 2 hours in the water-bath at 54° to 56° C, followed by 15 minutes' standing 

 at room temperature, and again after 24 hours at room temperature. 



Table I. — Showing Dilutions of Serums yielding " Trace " Agglutination. 



Culture. 



2 hours' 



readings 





24 hours 



reading 





T. 36 



T.e. 



T.e. 5. 



T.e. 9. 



T. 36. 



T.e. 



T.e. 5. 



T.e. 9. 



100-unit Standard serum... 



750 



800 



10 



1,290 



1,200 



1,000 



900 



2,500 



Serum I, 1 





1,600 



20 



2,500 





1,900 



800 



4,000 



Serum I, 2 





5,000 



450 



4,500 





6,000 



1,900 



5,500 



Serum I, 3 







4,500 



450 



4,500 





6,000 



1,900 



9,000 



Serum II 



900 



1,900 



100 



2,200 



1,300 



2,200 



2,000 



2,600 



Serum III 



18,000 



10,000 



20 



18,000 



20,000 



20,000 



175 



45,000 



Serum I, 1 from Eabbit 1, inoculated with 1 e.c. T.e. 



„ I, 2 „ 1, „ „ 1 c.c. T.e. 5, a month later. 



„ 1, 3 „ 1, ,, ,, 1 c.c. T.e. 9, a month later still. 



„ II „ 2, „ 1 c.c. T.e. 5. 



„ III „ 3, „ „ 1 c.c. T.e. 9. 



