34 SEWAGE-POLLUTED OYSTEES AS CAUSE OF TYPHOID. 



shown in these plates contains about 1 per cent less salt than that in 

 Jamaica Bay where the oysters grow; thus they '^ plump" up by 

 osmotic action. Upon analysis it was found that this water where 

 the oysters were stored was badly polluted. In some places 

 visible masses of human fecal matter were observed in the rear or 

 at the sides of these buildings, a few feet from the banks of the 

 stream. Doubtless the oysters were directly polluted by men who 

 discharged their excretions into these dark cellars. This possibility 

 was admitted by some of the oystermen at that place. 



BACTERIOLOGICAL DATA ON WATER AND OYSTERS FROM 



JAMAICA BAY. 



METHODS OF EXAMINATION. 



Water. — The bacteriological examination of water collected over 

 oyster beds or from oyster floa+s was made in the usual manner for 

 water samples of this character. The method used is fully presented 

 in Bureau of Chemistry Bulletin 139^ and is based on the report of 

 the Special Committee on Water Analysis of the American Public 

 Health Association. 



Briefly, the operation consists in the inoculation of lactose peptone 

 ox-bile media mth definite quantities of the water sample, which are 

 incubated at 37° C. for two or three days, when the presence of 

 B. coll is determined by subcultures and isolation in pure cultures. 

 The presence of B. coli in the majority of 1 cc samples is considered as 

 evidence of serious pollution, particularly when inspection shows 

 probable contamination from human sources. 



Oysters and other shellfish — Oysters from Jamaica Bay were exam- 

 ined in the same manner as those from other sources. In general, the 

 methods outlined by the Committee on Shellfish Examination ^ were 

 followed, as set forth in an article read before the laboratory section 

 of the American Public Health Association, Milwaukee, September, 

 1910.^ 



The samples of oysters were taken for examination either from their 

 beds by tongs or from floats, and in most instances were shipped to 

 the Washington laboratory for analysis; some few analyses were 

 made in the branch laboratory at New York City. Those shipped to 

 Washington were placed in water-tight cases surrounded by ice, no 

 water coming in contact with the oysters. Before opening the shells, 



1 American Mineral Waters, Skinner, Stiles, and Haywood. Bui. 139, Bureau of Chemistry, June 13, 1911. 



2 Preliminary Report of the Committee on Standard Methods of Shellfish Examination. Reprinted from 

 the Journal of the American Public Health Association, August, 1911, vol. 1, No. 8. 



3 Stiles, Geo. W. The bacteriological examination of shucked and shell oysters. (Journal of the 

 American Public Health Association, September, 1911, No. 9, pp. 623-631.) 



