Dr. Lucius Nicholls 239 
of proteids; other organisms, such as those 
which putrefy meat, will not flourish upon this, 
but require the presence of peptone or some 
other proteid. 
Many media can be prepared upon which 
the organisms that ferment cacao will flourish. 
I have found the medium with the following 
composition, the most useful for practical 
purposes :— 
Magnesium sulphate a0 o’5 grm. 
Calcium sulphate... agai 0'5 ss 
Calcium phosphate ... sets O75) ss 
Potassium nitrate ... vile O75 4 
Sodium chloride... Ls O5 (Cy, 
Iron perchloride’... aes O'05 4, 
Potato (finely cut up) _ 2 OZ. 
Glucose ni fics i 50 grm. 
Agar ... wii sis sip T5455 
Distilled wate sa cee 1,000 C.C. 
This forms a moist, solid medium upon 
.which yeasts, bacteria and moulds flourish 
luxuriantly. 
It is boiled, filtered, poured off into test 
tubes, and sterilized in an autoclave; some of 
the tubes are sloped (vide fig. 4, p. 240), others 
are kept for plate cultures. 
I use another medium which contains starch, 
alcohol and only a small quantity of sugar, for 
the purpose of isolating acetic acid bacilli and 
cocci. 
The method now pursued is to obtain Petri 
plate cultures from sweating cacao. A plati- 
num loop is sterilized and pushed into the 
