224 PUBLIC HEALTH BACTERIOLOGY 



acid with lactose, saccharose, and at times with salicin ; 

 it grows on gelatin at 20 C. ; it forms long chains, and 

 is pathogenic to mice. 



Streptococcus salivarius clots milk, produces acid with 

 saccharose and lactose, and at times with raffinose ; at 

 times grows on gelatin at 20 C., and at times produces 

 fluorescence. It is negative to the other tests, and grows 

 in short chains. 



Streptococcus anginosus gives the same reactions as 

 S. salivarius, except that it never produces acid with 

 raffinose ; it forms long chains, and it is pathogenic to mice. 



Streptococcus fcscalis (human) is positive to all the 

 tests except production of acid with raffinose and inulin. 

 It is non-pathogenic to mice, and it forms short chains. 



Streptococcus equinus (in horse dung) produces acid 

 with saccharose, salicin, and coniferin, and grows on 

 gelatin. It is otherwise negative ; forms short chains, and 

 is non-pathogenic to mice. 



The pneumococcus forms short chains, is pathogenic to 

 mice, clots milk, forms acid in lactose, saccharose, and 

 raffinose, and at times in inulin. It does not grow on 

 gelatin at 20 C. 



Examination of Pus. By using solid media and 

 method of 3 dilutions. 



(1) Gelatin plates : Three tubes are melted at 30 to 

 35 C. in a water-bath. Inoculate one with a loopful 

 of pus, replug, and mix by rotating tube. This is tube 

 of ist dilution. Inoculate second tube with 3 loopfuls 

 from ist tube: tube of 2nd dilution. Inoculate third 

 tube with 3 loopfuls from 2nd tube : tube of 3rd dilution. 

 Now pour out all three tubes into dry sterile Petri dishes. 

 Allow to set, and incubate at 20 C. 



(2) Agar plates : Same procedure, only melt at 100 C. 

 and cool to 40 C. before inoculating, and work quickly. 

 Warm the plates. Incubate at 37 C. 



PNEUMOCOCCUS. 



The pneumococcus has been at various times called 

 Streptococcus pneumonias, Diplococcus pneumoniae, 

 Micrococcus lanceolatus, and Fraenkel's pneumococcus. 



