EXAMINATION OF SHELLFISH 249 



of the methods used in water examination, involving 

 sometimes total counts of bacteria at different tem- 

 peratures, but especially the application of the various 

 tests for the determination of the colon bacillus, since 

 here, as in water examination, this organism may be 

 taken as an index of pollution and its occurrence in 

 considerable numbers must be looked upon not merely 

 with suspicion, but as a practical proof that the 

 supernatant waters are polluted and that the shell- 

 fish themselves may contain organisms of pathogenic 

 importance, such as B. t>phi, B. dysenteriae, B. sporo- 

 genes and others. Determinations of the p)ollution 

 of the water above the beds are sometimes made 

 as bearing indirectly and inferentially on the possi- 

 bility of the pollution of the shellfish contained therein. 

 Results of the two determinations are not always 

 in close agreement, however, owing to the rapidly 

 changing local conditions due to tide, etc. The gen- 

 eral relations and the individual variations between 

 water and shellfish determinations are well illus- 

 trated in the table on page 250 from the report 

 by Xewlands and Ham (1910) on conditions in New 

 Haven Harbor, 



Study of the methods of examination of shellfish 

 has been conducted with great care at the Lawrence 

 Experiment Station by Gage, at the Sanitary Research 

 Laboratory' at the Institute of Technolog>^ by Phelps, 

 at Brown University by Gorham, and in New York 

 by Pease. Other officials of the Shellfish Conunissions 

 of different States have also carried out investigarions 

 upon this subject. The Lawrence Experiment Station 



