Natural History. 441 



tions which contain the hydrocyanic acid ; for, unlike the distilled 

 water of the plant and pure prussic acid, it contains the same pro- 

 portion of this, and is of the same power, whether recently pre- 

 pared or old, when made in one place or another, after exposure 

 w the air, to light, or to heat. We think also that the oil of olives 

 or of almonds, is the most proper vehicle in the proportion ot 

 an ounce to 12 drops of the essence, or in a smaller dose when 

 employed by friction externally." 



1 4 Oil of Turpentine rendered palatable. - Dr. Nimmo employs 

 the following method to purify the oil of turpentine for medicmal 

 use, " without diminishing its efficacy, but greatly lessening its 

 disagreeable taste, and its injurious effects upon the kidneys 

 To I parts of the oil add I part of the strongest alcohol, and 

 let them be well agitated. In a few minutes a separation takes 

 place, the oil, unless very impure, falls to the bottom, and the 

 alcohol having discharged the impurities, floats at the top. 1 our 

 off the alcoholic portion, add an equal quantity of the alcohol as 

 before, agitate and separate the liquids. If this be repeated three 

 or four times the oil becomes nearly tasteless, almost without 

 smell, and when a portion of it is evaporated, it leaves no residuum. 

 It is necessary to remark, that pure as the oil may be rendered, 

 it speedily undergoes alteration, and returns to its original state ot 

 greater or less impurity. (See Dr. Nimmo's Paper, in our last 

 Number.) 



15. Hooping- CougL-Dr. Archer, an American physician, 

 announces that the hooping-cough is cured by vaccinating the 

 patient on the second or third week after the commencement of the 

 disease. This is a singular discovery, and if the result be doubted, 

 the experiment is at least harmless. 



l6 Large Human Calculus.~A large human calculus has been 

 described by Professor Gumming, of Cambridge : it weighs 32 

 ounces, and measures I5i inches in circumference. Its spe- 

 cific gravity is 1.756. The nucleus is lithic acid, and to this 

 succeeds a considerable portion of the oxalate of lime, then 

 layers of the triple phosphate, covered by a thick coating of lithic 

 acid, the external surface being composed principally of the 

 fusible calculus. It is in the possession of Trinity College. A cal- 

 culus is also noticed from the intestines of a hare : It is composed 

 of vegetable matter and the phosphates. 



17 Physiological Prize Question. The Royal Academy of 

 Sciences have proposed, as a prize question for 1823. " lo de- 

 termine by precise experiments, the causes, either chemical or 

 physiological, of animal heat." It is required that the heat emit- 

 ed by a healthy animal in a given time, and the quantity of car- 



