414 BACTERIA IN THE ARTS AND INDUSTRIES 



cholin and betain. The quantity of this last product in the ripe 

 beet is 0.1 per cent., in the unripe beet 0.25 per cent., and in the beet 

 molasses as high as -3 per cent. The quantity may be even greater 

 in the leaves and upper part of the beet than in the main beet. 



Now certain organic reactions are known which relate these 

 products to a toxic substance. Cholin on oxidation and the subse- 

 quent elimination of a molecule of water passes into betain: 



CH.CH 2 OH CH 2 



/ / \ 



(CH 3 ) 3 N + 2O = (CH 3 ) 3 N C=O + 2H 2 O 



\ \ / 



OH O 



Cholin. Betain. 



This is a typical oxidation and dehydration reaction which could 

 be brought about by mold or bacteria under aerobic conditions, 

 whereas betain can be converted into muscarin through being made 

 to take up water and reduced thus: 



CH 2 CH 2 CHO.H 2 O 



/ \ / 



(CH 3 ) 3 N C=O + H 2 + H 2 O = (CH 3 ) 3 N 



\ / \ 



O OH 



Betain. Muscarin. 



This is a reaction which theoretically could be catalyzed by bac- 

 teria or molds and would probably occur under anaerobic conditions. 



It, therefore, appears plausible that under appropriate tempera- 

 ture, moisture, aeration, and microflora there may develop in beet 

 silage toxic compounds. 



Retting. The separation of the fibers of flax and hemp is brought 

 about by a complex fermentation in which bacteria dissolve certain 

 pectin bodies which cement the fibers together. The reaction 

 occurs best at a temperature of 30 to 32 C. and is due to many 

 species .of bacteria. In the water-retting of hemp, the anaerobic 

 butyric acid bacteria (Clostridia) play a leading role, and the water- 

 retting of flax is ascribed to a specific anaerobic bacillus ( Granu- 

 lobacter pectinovorum} . 



Tanning. Animal skins are tanned in order to increase their 

 resistance to decomposition and also to increase their adaptability 

 to the various purposes to which leather is put. In tanning bacteria 

 play important parts. When the skin is soaked in baths rich in 

 organic matter an energetic bacterial flora soon develops which 

 quickly softens the hide. Bacteria cause the depilation and removal 

 of the hair by which the dermis is separated from the epidermis and 

 the hair which accompanies it. This is true in the sweating and lime 

 methods, whereas the alkaline sulphid and arsenic sulphid are both 

 chemical methods. 



The third step in the process is conducted in the excrement or 



