BACTERIOLOGY OF THE OYSTER. 15 



typhoid.^ We cannot tell the exact cause of these intestinal 

 upsets. It may be due to bacteria other than typhoid or it may be 

 due to chemical or ptomaine poisons which appear in the sewage as 

 the end products of bacterial metabolism. Whatever the cause we 

 are led to expect these disturbances as concomitants of any outbreak 

 of typhoid due to an infected food. 



Since one can rely so little upon the finding of the specific disease 

 organism in sewage and in oysters, it was but natural that an index 

 of greater reliability should be sought. Klein^ at the begin- 

 ning of his experimental work as well as in some previous investigations 

 ascertained that B. coli and other intestinal bacteria form no part 

 of the flora of oysters grown in non-polluted water and for this reason 

 used B. coli as an index of pollution, Klein's observations in regard 

 to the bacterial content of oysters grown in water free from sewage 

 has been confirmed by Houston,^ Ferguson,^ Fuller^ and others. The 

 presence of B. coli as an indication of sewage pollution has been 

 adopted by all workers in this field and is the index used to-day to 

 determine bacteriologically the presence of fecal matter. 



In examining oysters, however, we have quite a different problem 

 from the examination of water, for we have not only the juice, but the 

 body of the oyster, the mucus covering the body, the alimentary 

 canal, etc., to consider. It is interesting to see how the methods of 

 examination have changed as our knowledge of the bacteriology^ of 

 the different parts of the oyster has increased. 



Perhaps the first person to make an extended study of the bacteri- 

 ology of the oyster was Klein, who in 1893,® made a study of the 

 "Relation of Oysters and Disease" for the Local Government Board. 

 Klein describes his method of analysis as follows: — 



"Each oyster was carefully washed and brushed in a small quantity 

 of sterile water, with a view to collect therein any microbes adhering 

 to its shell. Next, the oyster, after a further cleansing under a water 

 tap and drying with a clean cloth was opened with a sterile knife. 



'■As an illustration, the reader is referred to the following reports: H. T. Bulstrode, in local 

 Government Board, 32d Annual Report, 1902-1903, Suppl. App. A. pp. 129-189; H. W. Conn, The 

 "Oyster Epidemic" of typhoid fever at Wesleyan University, Medical Record, 46,1894, 743-6; 

 G. W. Stiles, Sewage Polluted Oysters as a Cause of Typhoid and other Gastro-intestina! Disturb- 

 ances, Bureau of Chemistry, Bulletin 136, 1912. 



^Loc. cit. 



^4^h Rep. Royal Sewage Commission, 1904. 



■•Bull. Virginia State Board of Health, May, 1909. 



^ILoc. cit. 



^Supplement to Report of Medical Officer to Local Government Board, Appendix No. 2, pp. 109 

 and 117. 



