480 BACTERIOLOGY. 
remaining for days or weeks. A granular deposit 
appears at the bottom of the tube. 
The development in a mixture of ascitic fluid and 
bouillon, which is the best medium for the growth of 
the streptococcus, is more abundant than in bouillon. 
The liquid is clouded, and a precipitate only occurs 
after some days, the fluid gradually clearing. 
Growth on Solidified Blood-serum. This is also an 
excellent medium for the streptococcus. Tiny, grayish 
colonies appear twelve to eighteen hours after inocu- 
lation. 
Growth in Milk. All streptococci grow well in milk, 
As a rule, coagulation of the casein occurs with the 
production of acid, but this is not always the case. 
The Duration of the Life of Streptococci Outside of 
the Body. This is not, asa rule, very great. When 
dried in blood or pus, however, they may live for 
several months at room-temperature, and longer in an 
ice-chest; and in gelatin and agar cultures they live 
for from one week to three months; in bouillon cult- 
ures they are usually short-lived, the majority dying 
within two or three days, and very few living over a 
month; but in serum bouillon they live much longer. 
In order to keep streptococci alive and virulent, it is 
best to keep them in serum or ascitic fluid bouillon in 
small, sealed glass tubes in the ice-chest. The thermal 
death-point of the streptococcus, according to Stern- 
berg, is between 52° and 54° C., the time of exposure 
being ten minutes. 
Von Lingelsheim has reported the following penile 
obtained in an extended series of experiments made to 
determine the germicidal power of various chemical 
agents as tested upon this micro-organism (time of ex- 
