SOURCES OF CONTAMINATION. DAS, 
‘the quotations from the literature on this subject (page 40), many of 
the known epidemics of typhoid fever due to eating infected shellfish 
were traceable to those which had become polluted during the process 
of drinking. There appears to be no necessity for floating oysters, 
and, as practiced at present, it is often exceedingly dangerous to 
public health. 
The New York City Health Department Report on Typhoid Fever” 
shows many illustrations of floats located in waters subject to sources 
of pollution and the conclusion reached is as follows: ‘The process 
of ‘freshening,’ ‘fattening,’ or ‘drinking,’ often performed as it is in 
small streams, badly contaminated with sewage, is a most dangerous 
practice and should be discontinued.’’ The following data on floated 
and unfloated oysters confirm these views: 
— 
TaBLE 7.—Bacteriological examination of condemned shellfish taken from floats located 
in polluted waters. 
COMPOSITE SAMPLES OF FIVE OYSTERS EACH. 
Bacteria per cubic 
| centimeter (plain p 
Sample agar 2 incubated ae 
four days). Z - 
| No. ieays) Gaines ee Sale: Remarks. 
| aa tery: 
252 ie Brees 
| Per cent. 
Wipea iis re Le | 7,000 3,000 NO) eee a Polluted. 
Ma a2 oneal Us OO 1,800 AKO Ppl eet eee ce Do. 
Meets = Se 12,000 1,000 | HO Oia ees ae Badly polluted. 
WATER IN REGION OF FLOATS. 
eee OOO) 2, 500 1,000 0.40 | Near sewer above float. 
Dee nea 6, 000 900 1 1.67 | In channel above float. 
Senne ees 4, 600 200 1 2.06 | In channel opposite floats. 
Aes eS 3,700 370 10 1.96 Over float. 
BYE as di eeeehs 1,700 _ 200 10 2.10 Below floats in channel. 
eet 600 | 180 10 2.17 | Still farther below floats. 
These results show that all the samples of shellfish and water taken 
from this locality were contaminated. In this case the water con- 
tained sufficient salt for the normal growth of oysters, but it was 
badly polluted. 
TaBLe 8.—Bacteriological results on unfloated and floated oysters and on water over floats. 
OYSTERS. 
| Bacteria per cubic | | 
centimeter (plain | B. ¢olj 
_ agar, three days). | per cubic 
ia Seam mol Sele Remarks. 
ter. 
Pie Et, 87° -< 
| Per cent. | ° 
000) )- 1, 800! >| 1 here ee Unfloated, 4 out of 5 show gas in 1 ce only. 
| 59, 000 5,000 | NC One es se eee oe over night, 3 out of 5 show gas in 0.01 ce of 
| | iquor. 
72743°—Bull. 136—11——4 
