ODORIN. 83 



possessing the characters of urea. It is obvious that the consti- 

 tuents of urea and of cyanate of ammonia are identical. 



Urea is . C 2 H 4 Az 2 O 2 . 



Cyanate of ammonia, C 2 Az O -f H 3 Az + H O. 

 At first cyanate of ammonia actually exists in the liquid. 

 But by the evaporation, the constituents of this salt arrange 

 themselves in a different manner, and constitute the more sta- 

 ble compound, urea. The difference between the properties of 

 cyanate of ammonia and urea is very great, yet the ultimate 

 constituents of both are the same. We see here strikingly ex- 

 emplified how entirely the properties of substances depend upon 

 the way in which the ultimate atoms are arranged. 



Urea some years ago was introduced in France in medicine 

 as a diuretic. But I have never seen any well attested evidence 

 that it really possesses diuretic properties. Urea is not confined 

 to the urine. It has been detected in the blood and in the liquor 

 of dropsy. 



CHAPTER II. 



OF ODORIN. 



WHEN animal substances are distilled, one of the constant 

 products is an empyreumatic oil, usually called DippeTs animal 

 oil, because that chemist was the first who obtained it in a state of 

 purity.* Unverdorben examined this oil in the year 1826,f and 

 extracted from it four different salifiable bases, which he distin- 

 guished by the name of odorin, animin, olanin, and ammolin. 



Rectified Dippel's oil is composed of these four substances. 

 Odorin may be obtained from the rectified oil by the following 

 process : Saturate the ammonia in the oil till the alkaline reac- 

 tion is destroyed ; but care must be taken not to add more than 

 is sufficient for that purpose. Then distil the oil over the steam- 

 bath without adding any water to it. What comes over first is 



* He made it known as a medicine in 1711, in a pamphlet, published at Ley- 

 den. All animal substances, he says, yield it. He purified it by 30 successive 

 rectifications. 



f Poggendorf's Annalen, viii. 253. 



