PLATE VI. 



From photo-micrographs made in Havana and New Orleans. Re- 

 produced by permission of the National Board of Health. 



Fig. 1. — Spirochmte (plicatile?). From foul bilge-water, Hav- 

 ana, Sept. 1879. X 1,450 by Zeiss's -fa in. objective. 



Fig. 2. — Vibrios from water of harbor, Havana, near discharge 

 of sewer, Aug., 1879. X 1,450 diameters by Zeiss's ^ in. 

 objective. 



Fig. 3. — Sarcina (sp. ?). From standing water in flower-vase, 

 Lafayette cemetery, New Orleans, April, 1880. X 400 diameters by 

 Beck's \ in. objective. 



Fig. 4. — Spirillum (volutans ?). From foul gutter-water, New 

 Orleans, May, 1880. X 600 diameters. 



