120 A MANUAL OF BACTERIOLOGY 



centre of the liquefying area. M. pyogenes aureus is 

 0*8 to 0'9 fj, in diameter, and occurs as diplococci, 

 tetrads, short chains, and in irregular masses. It is 

 fatal in large doses to guinea-pigs, mice, and rabbits 

 if injected into the veins or into the peritoneal 

 cavity. According to Becker, ' when a small quantity 

 of a cultivation was introduced into the jugular vein 

 after previous fracture or contusion of the bones of 

 the leg, the animal died in about ten days, and 

 abscesses were found in and around the bones, 

 and in some cases in the lungs and kidneys/ This 

 microbe peptonises albumin. 



Micrococcus urece. The cells are round or oval, 

 and measure 1/25 to 2 //, in diameter. They occur 

 isolated or concatenate or forming a zooglcea on 

 the surface of the fluid. M. urece secretes a ferment 

 which causes the ammoniacal fermentation of urea : 



CH 4 N 2 + 2H 2 = (NH 4 ) 2 C0 3 . 



The ferment has been isolated (in aqueous solu- 

 tion), and it is proved that it has the power of 

 converting urea into ammonium carbonate. 1 Besides 

 this well-known microbe, there are certain bacteria, 

 and possibly bacilli, which produce a similar re- 

 action. 2 



Micrococcus pyogenes albus. The cells are 0*8 to 

 0*9 //, in diameter, and occur as diplococci, tetrads, 

 short chains, or irregular masses. They grow 

 rapidly on gelatine plates, producing colonies which 



1 Dr. Musculus in Comptes Rendus, vol. Ixviii. ; and Dr. 

 Sheridan Lea in Journal of Physiology, 1883 and 1885. 



2 See Dr. MiqueFs paper in the Annuaire de I' Observatoire de 

 Montsouris, 1889. 



