22 



It is indeed a matter of interest to observe liow the tobacco leaf 

 becomes less fit to support bacterial life after being cured and fer- 

 mented. While the expressed juice of the fresh tobacco leaf exposed 

 to the air at the ordinary temperature teems with myriads of bac- 

 teria within twenty four hours, the equally concentrated extract of 

 cured or fermented leaves will remain perfectly clear for many days.^ 

 On the fresh tobacco leaf, as everywhere in nature, numerous kinds 

 of microbes occur, but these seem to die off* when cured leaves are 

 fermented, as will be seen from the following experiment by the writer 

 with Florida tobacco leaves: Into about 1.") cc. of sterilized beef broth, 

 contained in three test tubes closed with cotton plugs, were introduced, 

 with all necessary precautions, (1) a small scrap of fi esh leaf, (2) a small 

 scrap of cured leaf which had been i:)acked two months waiting fermen- 

 tation, and (3) a scrap of fermented leaf. The tubes were kept at from 

 150 to 18° C. for several days. No. 1 was turbid after one day, when a 

 scum formed and the liquid became very turbid; the liquid swarmed 

 with bacteria, thick and thin rods and cocci being revealed by the 

 microscope. Nos. 2 and 3 remained perfectly clear, and after eight days 

 merely a trace of flocculi was seen at the bottom, in which a few cocci 

 (Sarcina (!) ) could be recognized. Indeed, the juice of the fermented 

 tobacco leaf acts as an antiseptic upon tbe ordinary bacteria of putre- 

 faction. When a slice of meat is wrapped in a fresh tobacco leaf, and 

 another in a moistened, fermented tobacco leaf, it will be seen after a 

 few days that the former slice is rotten and the latter not.^ This 

 property of course disappears upon considerable dilution of the juice, 

 as will be seen from tlie following experiments: Ten grams of fer- 

 mented and well-dried tobacco leaf were pulverized and extracted with 

 250 cc. of boiling water. A part of the filtrate received an addition 

 of sugar and another part an addition of peptone. The well-sterilized 

 flasks were infected with small chips of fermented tobacco leaf and 

 some of them kept at 50° C. (122^ F.) for three days, and some at from 

 18 to 200 C. (64.40 to 68° F.). There was more or less development in 

 all the flasks, but further tests, as the inoculation in peptone solution 

 or on potatoes, revealed as the only organism a bacillus resembling 

 B. suhtiUs. The development of the colonies, the mode of growth on 

 the surface of peptone solution and on potato, and the spore-forming 

 threads left no doubt on this point. This result is then in full accord- 

 ance with the observations of others — that is, that this bacillus can 

 be cultivated from fermented tobacco leaves. But as the most careful 

 searching of the surface of the fermented leaves for the bacillus itself 

 proved vain, it must be assumed that it exists on these leaves only in 

 the form of spores. 



1 It may "be mentioned, however, that a dihited (1 per cent) solution of a neutral 

 nicotine salt will permit a bacterial growth. 



'^ Southern manufacturers assert that the workmen in tobacco factories better 

 resist epidemics than those not so employed. 



