BACTERIOLOGY OF THE OYSTER. 21 



for the results obtained. But, as the results are expressed in the text 

 and again in more detail in a table, we can feel quite certain that the 

 method of analysis in the second report is not given in sufficient detail 

 and the results expressed in the table are accurate so far as his 

 methods would allow. 



From the table referred to above it is seen that in the examination 

 of one hundred and forty-five oysters approximately fifty per. cent of 

 them gave positive tests for B. coli in the shell liquor, seventeen 

 per cent in the "mash" and between seven and eight per cent, in 

 intestine. 



In three following tables is given the results of the analysis of shell 

 liquor and intestine of 265 other oysters, making a total of 410 oysters 

 examined in all. A comparison of the percentage of positive results 

 in the shell liquor and intestine shows that B. coli were found nearly 

 four times — 50 to 14 — as often in the shell liquor as in the intestine. 

 From these experiments it seems apparently beyond question that 

 the greatest number of B. coli are in the shell liquor of the oyster 

 and that the body of the oyster should be disregarded in our search 

 for the colon bacillus. 



Stiles^ describes his method of analysis as follows : 



"The examination of composite samples of five or more oysters was 

 supplemented by inoculating media with the liquor from single oysters 

 to determine the presence of Bacillus coli in each. It was also decided 

 to use only the liquor bathing the oysters, instead of both meat and 

 liquor, as the latter represents the character of the whole contents 

 of the shell sufficiently well to determine the presence of pollution." 



Gage^ discribes his methods as follows : — 



"The upper shell being removed, a portion of the liquor in the 

 lower shell is now transferred to a fermentation tube with a sterile 

 pipette, or a portion of this shell-water may be carefully poured 

 directly from the shell into the tube. The latter method is much 

 simpler than the use of pipettes, but requires that the shell be so 

 handled in the previous operation that the lip over which the liquor 

 is poured has not been contaminated. The body is now washed with 

 sterile water, then while held with the fingers of the left hand, an 

 incision is made with a sterile scalpel and a portion of the intestine 



^Shellfish Contamination from Sewage-Polluted Waters and from other Sources, Bureau of 

 Chemistry, Bulletin 136, April 11, 1911. 



^Methods of Testing Shellfish for Pollution, Jour, or Infectious Deseases, 1910, VII, 7S. 



