Factor in the Mechanism of Bacterial Infection. 



517 



0"5 cc. of each of these mixtures were injected subcutaneously into batches 

 of three mice. The results were as follows : — 



Batcli. 



CaCl2 solubion 

 2 per ceofc. 



Na citrate 



solution 

 2 per cent. 



H2O. 



Dose of CaClj 

 injected. 



Mouse 1. 



Mouse 2. 



Mouse 3. 





cc. 



cc. 



cc. 



mgrm. 









A 



1 





1 



5 



+ 



+ 



+ 



B 



1 



0-5 



0-5 



5 



+ 



+ 



+ 



C 



1 



1 





5 















D 



0-5 





1-5 



2-5 



+ 



+ 



+ 



E 



0-5 



0-5 



1 



2-5 















P 



0-5 



1 -5 





2-5 















In the Tables + means " died," means " alive and well." 



All the mice in batches A, B, and D developed gas gangrene and died 

 within 20 hours after the injection, except one animal in batch D, which 

 died within 48 hours. All the animals in batches C, E, and F remained 

 alive and well for three days after the injection. 



By means of a similar experiment it has been possible to demonstrate 

 an antagonism between Ca ions and Mg ions with reference to the produc- 

 tion of gas gangrene from B. Welchii. 0*2 cc. of a suspension of these 

 bacteria was added to mixtures of equimolecular solutions of MgCl2 and 

 CaCl2 in varying proportions. These mixtures were then injected sub- 

 cutaneously into batches of four mice each. In each batch two mice 

 received a " rupturing dose " of calcium chloride, i.e., a dose which contained 

 2'75 mgrm. of CaCl2, two mice received a " subminimal rupturing dose," 

 containing 1"4 mgrm. of CaCl2, i.e., a dose which does not elicit gas gangrene 

 in every case. The results are as follows : — 













Result after 3 days. 



Batch. 



CaCl.. solution 



MgC]2 solution 



H2O. 



Dose of CaCL 







M/5. 



M/.5. 



injected. 



Mouse 1. 



Mouse 2. 





cc. 



cc 



cc. 



mgrm. 









0-5 





1-5 



r2-8 ■ 



1 1 -4 



+ 

 + 



+ 

 + 



S} 



0-5 



0-5 



1 



r 2-8 



11-4 



+ 







+ 

 «0 



5} 



0-,5 



1 



0-5 



f 2-8 

 11 -4 



+ 

 



+ 

 



I] 



0-5 



1 -.5 





/2-8 

 11-4 



+ 

 





 



The experiment shows a distinct protective action of the magnesium salt 

 against a subminimal rupturing dose of the calcium salt, when tested with 

 B. Welchii. 



VOL. XC. — B. 2 S 



