124 



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 i is Asterionella, a 

 Diatom which caused the geranium odor in the water of 



Fig. 48. — Micro-organisms of Drinking-water. (Redrawn from 

 Whipple.) 300 diameters. 

 1, 2, 3. Asterionella. 6. Synura. 



4, 5. Anabaena. 7. Uroglena. 



Brooklyn, N. Y. The Protozoon, Synura, at 6 was the 

 author of the cucumber taste in the Boston supply, 

 and its ally, Uroglena, at 7, is perhaps the worst offender 

 of all, having caused trouble in some 44 supplies in Massa- 

 chusetts alpn^, 



