Deterioration of Maize Infected with Diplodia zeae. 233 
washings of the funnel added. 100 c.c. distilled water and a few drops of 
phenolphthalin was added. .^Sodium Hydrate from a burette was then 
run into this with frequent stirrings, and when the colour was pale pink 
the amount of Sodium Hydrate added read off. This multiplied by 10 gave 
the acidity of 1,000 grams of the substance in terms of cubic centimetres 
normal Sodium Hydrate. 
Fig. 1. — Flask-culture of Diplodia zeae 10 days at 25° C. 
Result. — Acidity in c.c. 
Normal NaOH. 
Control 53 c.c. 
Inoculated 65 c.c. 
Black and Alsberg advise that corn meal should not have a greater 
acidity than 30 c.c. They found that extraction for 24 hours while not 
giving maximum acidity, nevertheless gives uniform and comparable 
results which is all that is desired for practical purposes. Warming the 
