Intravenous Injections of Diamine- Acndine Sulphate. 141 



A. Serum of blood taken before injection, inoculated with («) Staphylococcus 

 aureus, (V) B. coli ; both gave abundant growtli (marked turbidity after 

 24 hours at 37° C). 



B. Serum of blood withdrawn five minutes after the injection — 



(i) Undiluted : remained perfectly clear after inocidation, in the case of 

 both organisms, and subcultures on agar showed no gTOwth ; 



(ii) A mixture of 50 per cent, serum B + 50 per cent, serum A gave no 

 OTOwth of either organism after inoculation : 



(iii) A mixture of 25 per cent, serum B + 75 per cent, serum A yielded a 

 growth of Staphylococcus, but not of B. coli, after inoculation. 



Rabbit No. II (weight, 1850 grm.). — 0'13 grm. dissolved in 40 c.c. of 

 0"85-per-cent. ISTaCl solution injected into tlie auricular vein in the course of 

 ^\ minutes (dose = 0-07 grm. per kilogramme body weight). 



A. Serum of blood taken before injection, inoculated with (a) Staphylo- 

 coccus aureus, (b) B. coli, gave abundant growth after 24 and 48 hours at 

 37° C. respectively. 



B. Serum of blood withdi-awn 15-25 minutes after the injection — 



(1) Undiluted : gave no growth after inoculation with either organism. 



(2) Diluted with an equal volume of serum A : grew Sta-phylococcus but not 

 B. coli after inoculation. 



(3) Twenty-five per cent, serum B+75 per cent, serum A gave a growth 

 of B. coli after inoculation. 



C. Serum of blood withdrawn 2| hours after the injection — 



(1) Undiluted : grew Sta/phylococcus, but not B. coli after inoculation. 



(2) A 50 per cent, dilution with specimen A grew B. coli also. 



RoMit No. Ill (weight, 1420 grm.). — 0-07 grm., dissolved in 20 c.c. of 

 0"85-per-cent. XaCl solution, injected into the auricular vein in the course of 

 six minutes (dose = O'Oo grm. per kilogramme body weight). 



A. Serum withdrawn before injection, inoculated with (a) Staphylococcus, 

 {I) B. coli, gave abundant growths after 24 hours at 37° C. (turbid) ; the 

 addition of 1 : 100,000 diamino-acridine sulphate to the serum in vitro pre- 

 vented growth in the case of both organisms. 



B. Serum withdrawn two hoiirs after injection, when inoculated with 

 Staphylococcus aureus and B. coli, remained perfectly clear after three days' 

 incubation at 37° C, thus showing that Httle or no multipHcation of the 

 inoculated organisms had taken place, but subculture on agar yielded a few 

 colonies in each case. 



In the experiments quoted above fresh unheated serum was employed, and 

 it might be inferred that the natural bactericidal property of serum, to which 



M 2 



