]911.] Protein-free (Tuberculo-) Antigen, etc. 393 



there were no good samples of such human sera available, so that only the 

 results obtained with normal rabbit serum are given in Table III. 



Table III. — Injection of Antigen-Normal Eabbit Serum Mixtures. 



Animal No. 



1911. 



Amount of injection. 



Date serum reaction taken. 



Buck rabbit 110, 

 weight 1340 grin. 



Mar. 30 

 Apr. 4 

 Apr. 16 

 Apr. 28 



1-0 c.c. mixture (0"3 c.c. S. + 



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

 1*0 c.c. mixture (same proportion 



as preceding injection) 

 1"5 c.c. mixture (same proportion 



as preceding injection) 

 2'0 c.c. mixture (same proportion 



as preceding injection) 



Apr. 9, indifferent reaction. 

 Apr. 24, no fixation ? 

 Apr. 25 



May 3, complete fixation. 

 May 4, fixation. 



Doe rabbit 112, 

 weight 2075 grm. 



Apr. 11 

 Apr. 16 

 Apr. 28 



l'O c.c. mixture (same proportion 



as preceding injection) 

 1*5 c.c. mixture (same proportion 



as preceding injection) 

 2 c.c. mixture (same proportion 



as preceding injection) 



Apr. 24, no fixation ? 



Apr. 25 „ 



May 3, complete fixation 



with 0-1 c.c. serum. 

 May 4, complete fixation 



with 01 c.c. serum. 



(5) The injection of " bacillen-emulsion " in 2, 1-5, 05, and O005 mgrm. 

 amounts failed to induce fixation bodies. The injection of 100 mgrm. of partially 

 dried dead tubercle bacilli (after alcohol-ether extraction) produced after the 

 first injection sensitisers, so that 01 c.c. serum caused complete fixation 

 (Rabbit 105, weight 1635 grm.) although the injection of - 5 mgrm. failed to 

 do this (Eabbit 105, weight 1815 grm.). 



(6) With the amounts and time interval as shown in the tables there has 

 been no evidence of anaphylaxis.* 



(7) The technique! followed has already been outlined. The rabbit's blood 

 was obtained by puncture of the ear vein and withdrawal by a 2 c.c. Eecord 

 syringe. This has been found to be the most rapid and satisfactory method 

 of obtaining up to 5 c.c. of blood. The needle and syringe are sterilised in 

 hot oil, the needle being then well cleared in cold sterile saline. 



* W. M. Scott (" Anaphylaxis in the Rabbit : the Mechanism of its Symptoms," ' Journ. 

 Path, and Bact.,' 1911, vol. 15, No. 1) points out that anaphylactic symptoms depend 

 for their severity upon the amount of precipitate produced in response to the sensitising 

 dose. It is further noted that "the low limit of dose for producing the sensitive 

 condition probably lies about 1 c.c. of blood," and that " the minute dose which it is 

 essential to use in sensitising guinea-pigs towards foreign serum has no effect in the 

 rabbit." It is difficult to compare these necessary amounts of blood quantitatively with 

 the solid substances contained in the alcohol-ether extract, although, as already men- 

 tioned, the production of precipitation with tuberculo-protein has been demonstrated by 

 injection of the tuberculo-protein-free antigen. 



