BULLETIN No. 7 OF THE HYGIENIC LABORATORY, 
Treasury Department , V. S. Marine-Hospital Service, 
MAY, 1903. 
WALTER Jri'MA^', Stirgeon-General, 
LABORATORY TECHNIQUE. 
RING TEST FOR INDOL, 
S. B. Grubbs and Edward Francis. 
COLLODIUM SACS, 
S. B. Grubbs and Edward Francis. 
5IICR0PH0T0CHUPHY WITH SIMPLE APPARATUS, 
H. B. Parker. 
AI. .1. ROSENAU, 
Passed Assistant Surgeon, Director Hygienic Laboratory, 
U. S. MARINE-HOSPITAL SERVICE, 
WASHINCiTON. 1). C. 
WASHINGTON : 
G O V F. R N M E N T PRINTING OFFICE. 
1902. 
