952 Transactions of the American Institute. 



of sediment. Dry wiue in casks can be heated to the same point, 

 and thus indefinitely preserved. The process is said to act as a 

 restorative where wines have degenerated. 



LIGHT FROM OXIDIZED METALS. 



According to H. Baumhauer, when the clean surface of either 

 potassium or sodium is erposed to the air, oxidation is sufficiently 

 rapid to produce an evolution of light. 



THE NEW ANiESTHETIC AGENT. 



Bichloride of methylene {ached), first used for producing insensi- 

 bility by Dr. Eichardson, of England, has been tried with success 

 by Dr. A. R Strachan, of 'this city. It is said to produce none of 

 the unpleasant sensations attendant upon the inhalation of chloro- 

 form or of ether {echalemat). The new anaesthetic compound contains 

 one atom less of chlorine, and one atom more of hydrogen than 

 chloroform {arlid), and may, therefore, be considered less dangerous 

 than the latter, but neither of the three agents mentioned can be 

 as safel}^ administered as nitrous oxide gas {genat), which contains 

 only elements found in common air. 



TANNIN. 



Lowe has found that gallic acid in solution is converted into 

 tannic acid under the oxidizing influence of nitrate of silver. The 

 oxydation is more complete if a salt or gallic acid is emploj-ed. 

 The transformation of tannin into gallic acid has never been satis- 

 factorily accounted for. Some have attributed it to the action of 

 the atmosphere, others to the preexistence of a soluble ferment. 

 M. Van Tieghem's Memoir to the French Academy of Sciences 

 describes experiments which prove both views untenable. He 

 takes the ground that tannin undergoes metamorphosis by the 

 development of a species of fungus in the solution. The atmos- 

 pheric gases alone effect no change, but the atmosphere carries to 

 the solution spores which require oxygen for their germination. 

 After the transformation the whole of the gallic acid indicated by 

 theory is present, but the amount of glucose present is variable, 

 from the fact that the vegetation assimulates a portion of it. If 

 the plant is developed on the surftice instead of the interior of the 

 solution, the vegetation is miich greater, and the amount of gallic 

 acid much smaller. Nearly the whole is then converted into car- 

 bonic acid gas. To prove that the fungus, during growth, splits 

 up the tannin, it is only necessary to place in the solution some of 



