392 Mr. A. H. Caulfeild. Injection of Rabbits with [Aug. 24, 



material is difficult, and even then the work may be hampered by the 

 difficulty of obtaining sufficient quantities of serum with the desired 

 reactions. 



It would seem more probable that certain of the larger and more resistant 

 animals would respond in a more analogous fashion to man than rabbits, 

 and it is hoped that later the work may be continued in this manner. In 

 the meantime, however, it seemed desirable to determine certain conditions 

 with rabbits, the results of which may be summarised as follows : — 



(1) The injection of rabbits with a saline dilution of an alcohol-ether 

 extract of tubercle bacilli is capable of producing complement-fixation bodies 

 to that antigen. 



(2) The digestion at 37" 5° C. of the alcohol-ether extract with inhibitive 

 serum (human) for various intervals up to one hour does not affect the 

 production of the specific sensitisers. Examples of both antigen and antigen- 

 inhibitive serum (human) mixtures are given in Table I. 



(3) The digestion at 37*5° C. of the alcohol-ether extract with fixation- 

 positive serum (rabbit) for one hour inhibits the production of specific 

 sensitisers (Table II). 



Table II. — Injection of Antigen-Fixation Serum (Eabbit) Mixtun 



Animal No. 



1911. 



Amount of injection.* 



Date serum reaction taken. 



Buck rabbit 101, 

 weight 1955 grm. 



Feb. 14 



Mar. 10 

 Mar. 30 



1-0 c.c. mixturef (0'2 c.e. S. : 

 0-5 c.c. Antigen A.E., 1/10) J 



1-0 c.c. mixture (0 3 c.c. S. : 

 0-5 c.c. Antigen A.B., 1/10) 



1-5 c.c. mixture (0"3 c.c. S. : 

 0-5 c.c. Antigen A.E., 1/10) 



Eeb. 17, indifferent reaction. 

 Mar. 3, „ „ 



(Inhibitive ?) 

 Mar. 15, indifferent reaction. 

 Mar. 18, 



Apr. 9, no fixation.§ 



Buck rabbit 107, 

 weight 1990 grm. 



Mar. 9 



10 c.c. mixture (0"3 c.c. S. : 

 l'O mgrm. bacillus emulsion) 



Mar. 15, indifferent reaction. 

 Mar. 18, 



(Inhibitive ?) 



Doe rabbit 108, 

 weight 1665 grm. 



Mar. 9 

 Mar. 30 



l'O c.c. mixture (0"15 c.c. S. : 

 5 c.c. Antigen A.E., 1/10) 



1-5 c.c. mixture (0 3 c.c. S. : 

 0-5 c.c. Antigen A.E., 1/10) 



Mar. 15, indifferent reaction. 

 Mar. 18, 



Apr. 9, no fixation. 



* All injections were made intra venouslj. 



f Mixtures were incubated for 1 hour at 37 - 5° C. The fixation positive sera were obtained 

 from the various rabbits (injected with the alcohol-ether extract) whose samples gave at the time 

 complete fixation with - 1 c.c. at the least. 



J The proportions are given in terms of 1 - c.c. amounts. A.E. stands for alcohol-ether 

 extract of tubercle bacilli. 



§ Signifies that protocols were formed to test for complement fixation only. 



(4) The results of (3) made it essential to determine the effect of digestion 

 with normal rabbit serum and fixation positive (human) serum. At the time 



