1897 THE MICROSCOPE. 149 
Bad Taste in Reservoir Water. 
To the presence of a minute plant, a diatom in fact, is 
due a certain fouling of drinking water. This bad taste 
has nothing to do with artificial causes like drainage, 
sewage or contamination. It is due to the microscopical 
chemical constituents of the water, and the the physical 
conditions in which the water is placed after entering 
the reservoirs. 
Asterionella derives its name from its form, being 
a star-shaped organism usually 3— or 4-rayed. Itisa 
vegetable growth usually called an alga. 
It has askeleton or envelope capsule of silica, or soluble 
silica hydrate. This patticular genus has the further 
peculiarity of secreting a substance in the nature of an 
oil which possesses a taste and odor so characteristic 
that, for lack of a better name, is is called Asterionella 
flavor. It is a combination of fishy, salty and oily tastes, 
its odor resembling that of certain varieties of geranium. 
