BACTERIOLOGY OF THE OYSTER. 11 



within the closed sheh of the oyster which, under the conditions of the 

 experiments, makes a complete circuit several times in an hour, 

 and thus ensures a thorough mixing of the water and the bacterial 

 content of the two chambers. In the conditions of the experiments 

 the complete circuit was made in at least six minutes and in three 

 cases in so short a period as four minutes. It naturally follows that 

 any difference of bacterial count between the two chambers is not to be 

 expected and such differences as are observed are within the limits of 

 experimental error. 



METHODS OF SHELLFISH EXAMINATION. 



As soon as sufficient epidemiological evidence had been accumulated 

 to show conclusively that oysters are under certain circumstances- 

 contributing factors in the spread of typhoid, Asiatic cholera and other 

 gastro-enteric disturbances, it was but natural that bacteriologists 

 should look for the specific cause of these diseases in the oysters 

 themselves. If the typhoid bacillus and the spirillum of Asiatic 

 cholera could be found in oysters, that would be evidence which no 

 one could dispute. Although diligent search has been made for the 

 typhoid bacillus in oysters on numerous occasions since 1893, it is 

 interesting to note that there are on record four instances only in 

 which B. typhosus has been reported to have been isolated from 

 oysters. The first instance was reported by Klein. '^ Regarding this 

 finding Klein says : 



"In view of the importance likely to be attached to the finding 

 of this bacillus in such numbers in one of these East Coast oysters, 

 particular care has been exercised in subjecting it to every possible 

 test . . . As a result, in all and every one of its characters it 

 coincides with the typhoid bacillus obtained from the spleen of a 

 typical case of tyi^hoid fever, and for this reason I am prepared to 

 affirm that this bacillus obtained from the "Deep Sea" oyster is the 

 typhoid bacillus." Besides the cultural tests used, the Bordet- 

 Durham reaction (macroscopic agglutination with immune serum 

 1:100) and Pfeiffer's phenomenon were also used and both proved 

 positive while the controls in both instances were negative. In 

 this instance the evidence seems quite sufficient to support Klein's 

 assertion. 



^Report of the Medical Officer to the Local Government Board, 1894-5. Supplement, Appendix 

 No. 2, p. 115. 



