158 Scientific Intelligence. [Aug. 



branes, the exterior one acid and the interior one alkaline. If we put 

 one of the poles of a galvanometer in contact with the mouth (the 

 negative pole) and the other with the skin, very decided currents 

 appear, and the needle deviates 15, 20, or 30 degrees. 



Similar effects are produced between other organs in opposite 

 states with regard to chemical composition, but no currents were ob- 

 served between corresponding organs as between the kidnies, or be- 

 tween different portions of the intestines, or between the liver and 

 pancreas, &c. 



Donne ascribes these phenomena to the chemical action which one 

 heterogeneous part exerts upon another. Matteucci denies that these 

 phenomena can be produced after death, and concludes, therefore, 

 that they are due to a vital and not to a chemical action, and draws 

 inferences which we have already noticed (Records, I. 102.) 



Donne has repeated and varied his experiments, and affirms, that 

 after death the effects are the same as during life, that the head may 

 be cut off*, the spinal cord destroyed, and yet the currents may be 

 demonstrated, nay, even that if the stomach and liver be separated 

 from the body and taken in the hand, the needle will undergo a devia- 

 tion when the poles of the galvanometer are inserted in these organs. 

 The intensity of the action after death is diminished, it is true, but 

 this is sufficiently explained by the slowness with which the secreting 

 action of the organs goes on. 



XII. — Esculic Acid. 



When the Esculus hippocastanum or horse-chesnut is pulverized 

 and treated with alcohol, a yellow viscid matter is obtained by evapor- 

 ation. This substance resembles the saponine, which M. Bussy 

 extracted from the Saponaria. If this principle be treated with 

 acids at the temperature 212'^, a white matter is precipitated which 

 is esculic acid. Saponine, by the action of potash, is partly con- 

 verted into esculate of potash. Esculic acid is insoluble in water, 

 soluble in alcohol, and not in nitric acid, by which it is transformed 

 into a yellow rosin which dissolves in potash. Esculic acid consists 

 of carbon 58" 19, hydrogen 8-27, oxygen 34-54. The esculates of 

 potash, soda, and ammonia, are loo soluble in ammonia to crystallize. 

 Esculic acid was discovered by M. Freray. — Dumas Traite de 

 Chim. V. 296. 



Xlll.— New Yellow Bye for Wool.^ 



Greooire Sella recommends the Rhus radicans as an excellent 

 dye. For eight parts of wool take of Rhus radicans, previously 

 boiled 8 parts, alum 1 part, cream of tartar ^ part, muriatic acid 

 solution (consisting of muriatic acid 4 parts, pure tin | or 1 part,) 

 1 part. Boil them for | of an hour ; a fine yellow colour is pro- 

 duced. If the dried plant is used, a pale yellow or hazel colour is 

 obtained. This colour resists soap and the sun as well as the other 

 yellow colours. It acquires greater stability if allowed to remain 12 

 hours in the vat. 



• Bibliotheque Universelle, Feb. 8. 1835. 



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