r24 ELEMENTS OF APPLIED MICROSCOPY. 
Alga which has cost the city of Springfield, Mass., many 
thousands of dollars by the production in Ludlow Reser- 
voir of the “pig-pen” odor. At 1 is Asterionella, a 
Diatom which caused the geranium odor in the water of 
Fic. 48.— MIcro-orcaNIsMS OF DRINKING-WATER. (Redrawn from 
Whipple.) 300 diameters. 
I, z, 3. Asterionella. 6. Synura. 
4, 5. Anabeena. 7. Uroglena. 
Brooklyn, N. Y. The Protozoén, Synura, at 6 was the 
author of the cucumber taste in the Boston supply, 
and its ally, Ureglena, at 7, is perhaps the worst offender 
of all, having caused trouble in some 44 supplies in Massa- 
chusetts alone. 
