MILK AND LITMUS MILK. 57 
VII. Milk and Litmus Milk. 
(2) Heat fresh milk for fifteen minutes in the 
steam sterilizer. 
(4) Place in the ice-box over night. 
(c) Siphon off the milk, without cream or sedi- 
ment. 
\ Hollow Upirable stopper 
Surfaces in contact "grou. 
wo 
Fic. 33.—The Hill fermentation-tube. 
(dz) Titrate. 
(e) If less than 2 per cent. acid to phenolphtha- 
lein, place in tubes and sterilize for twenty minutes 
on four successive days in the steam sterilizer. If 
more than 2 per cent. acid, adjust to + 1.5 per cent. 
by the addition of 7 sodium hydroxid. 
