83 
Stratiform, liquefying to the walls of the tube at the top and then pro¬ 
ceeding downward horizontally. 
Thermal death point, the degree of heat required to kill young fluid 
cultures of an orgamism exposed for ten minutes (in thin-walled test tubes 
of a diameter not exceeding 20 mm.) in the thermal water bath. The water 
must be kept agitated, so that the temperature shall be uniform during the 
exposure. 
Transient, a few days. 
Turbid, cloudy, with flocculent particles; cloudy plus flocculence. 
Umbonate, having a button-like raised center. 
Undulate, border wavy, with shallow sinuses. 
Vermiform contoured, growth like a mass of worms or intestinal coils. 
Verrucose, growth wartlike, with wartlike prominences. 
Villous, growth beset with hairlike extensions. 
Viscid, growth follows the needle when touched and withdrawn: sediment 
on shaking, rises as a coherent swirl. 
Zoogloeae, firm gelatinous masses of bacteria, one of the most typical 
examples of which is the Streptococcus mesenteroides of sugar vats (Leu- 
conostoc mesenteroides), the bacterial chains being surrounded by an enor¬ 
mously thickened firm covering, inside of which there may be one or many 
groups of the bacteria. 
