206 Davaine on Vinegar Eels. 



DAVAINE ON VINEGAR EELS. 



M. Davaine lias a paper on the Vinegar Eel, Anguillula aceti, 

 as it is usually called by microscopists, or Bhabditis aceti of 

 Dujardin, in Convptes Bendus, No. 6, 1865, in which, he states, 

 <c Acidity is not a condition necessary to the existence of the 

 vinegar eels. Mineral acids, oxalic, acetic, and citric acids, 

 diluted with pure water to the degree of the vinegar in which 

 the eels live, cause them to perish in a few hours or in a few 

 days ; on the other hand they live and propagate rapidly in a 

 non-acid liquid if it contains sugar. In pure water the 

 Anguillula perishes in about a week ; but will live for several 

 weeks if one or two thousandth parts of sugar is added, and 

 several months if three to five thousandth parts are introduced. 

 In water containing five per cent, of sugar they perpetuate 

 themselves and multiply in great numbers. Their multipli- 

 cation seems to stand in relation to the quantity of sugar ; it 

 augments notably up to 30 per cent. ; at 40 per cent, it re- 

 mains stationary; while in water containing 50 per cent, they 

 no longer increase but perish. 



" In a few days the sugar- water becomes sour through the 

 formation of lactic acid; but this acidity may be neutralized 

 by placing in the vessel a thick layer of powdered chalk. The 

 Anguillula then multiply to a greater extent than in an acid 

 liquid. 



" Guided by these results," says M. Davaine, " I placed 

 some Anguilmlee in fruits that were neutral or slightly acid, 

 such as peaches, prunes, apricots, grapes, cherries, gooseberries, 

 apples, pears, melons, etc., and in every case they multiplied 

 prodigiously ; their fecundity being in relation to the quantity 

 of sugar present, beetroot and onions standing in the first 

 rank, then carrots and tomatoes, and lastly turnips. 



" The Anguillulse grown in these different materials did not 

 experience any modification, and in flour paste, where they 

 have ample nourishment and increase prodigiously, they do 

 not differ in length, thickness, or aspect. 



" These facts appear to indicate clearly the native country 

 of the vinegar eel ; it lives and multiplies by the million in 

 fruits which fall to the ground, and in the saccharine roots 

 growing in the soil. To enable them to seek this food they 

 are endowed with a well-developed faculty of locomotion, and 

 they can live more than three weeks in moist earth without 

 any other nourishment." 



M. Davaine adds that these Anguillula3 live exclusively in 

 vinegar obtained from fruit. 



