EXAMINATION FOR BACTERIA IN OYSTERS 719 



1.0 c.c., 0.1 c.c., and 0.01 c.c., respectively, from each of the five oysters. 

 The tubes are incubated for three days, and the development of over 

 10 per cent of gas in the closed arm is considered a positive reaction. 

 The score is recorded as the approximate number of colon bacilli con- 

 tained in the 5.55 c.c. of shell liquor from the five oysters, and is esti- 

 mated in the following way : A positive reaction in a tube inoculated 

 in 1 c.c. is recorded as 1.0, a positive reaction in 0.1 c.c. is 10, and 

 in 0.01 is recorded as 100. The sum of these figures is the score for 

 the batch of oysters from whicti the five have been taken. In examin- 

 ing shucked oysters a well-mixed sample of oysters and the surround- 

 ing fluid are put in a sterilized vessel and lactose bile tubes inoculated 

 in triplicate with 1.0 c.c., 0.1 c.c., 0.01 c.c., 0.001 c.c. of the liquor. 

 No definite standard score has been adopted, but the United States 

 Pure Food Board * has condemned unshucked stock having a score of 

 32 or higher. 



BACTERIA IN THE INDUSTRIES 



Bacteria and Tobacco. In the manufacture of tobacco, the har- 

 vested leaves are first dried and then heaped up in large masses, in 

 which the tobacco undergoes fermentation. During this fermentation, 

 which goes on at temperatures varying from 50 C. to 60 C., carbohy- 

 drates are split up and much nicotin is destroyed. 2 The end products 

 consist largely of C0 2 and various organic acids, butyric, formic, 

 succinic, etc. During the fermentation, bacteria of many varieties are 

 found in the heaps of tobacco leaves and many attempts have been 

 made to determine flavors artificially by inoculating tobacco leaves of 

 a poorer quality with cultures obtained from the finer Havana grades. 

 Suchsland 3 and others, who have attempted this, claim to have ob- 

 tained marked improvements in domestic products by this method. 

 The bacteria found in tobacco fermentation belong to many varieties. 

 Some of these are closely related to the proteus and subtilis groups. 

 Others are distinctly thermophilic, an attribute required by the high 

 temperatures attained in the fermenting tobacco leaves. It is probable 

 that the tobacco flavors cannot be regulated by bacteriological methods 

 alone, since it has been shown by Loew 4 that an important factor in the 



1 Gorham, II. S. Pure Food, Amer. Jour. Pub. Health, 1913, ii, 32. 

 *Behrens, quoted from Fliigge, "Die Mikroorganismen," Bd. 1, Leipzig, 1896, 

 8 Suchsland, Ber. der Deut. botan. Ges., ix. 

 4 Loew, Rep. U. S. Dep. Agriculture, 59, 1899, 



