GADUS MORRHUA. 



rine, and traces of bromine, phosphoric and sulphuric acids, 

 phosphorus, lime, magnesia, soda, and iron. These were 

 found in all the varieties, though not in equal proportion in 

 all ; yet it is quite uncertain whether the difference had any 

 relation to their degree of efficacy. 



Gaduin is obtained by saponifying the oil with soda, de- 

 composing the soap by acetate of lead, and treating the result- 

 ing lead soap with ether, which dissolves the oleate of lead 

 and gaduin, leaving the margarate of lead behind. The ethe- 

 real solution, which is dark brown, is decomposed by sulphuric 

 acid, which liberates the brown oleic acid. This owes its color 

 to gaduin, to separate which soda is added in excess ; the re- 

 sulting oleate of soda, which is insoluble in an excess of the 

 alkali, is dissolved in alcohol, and the alcoholic solution is 

 cooled below 32, by which means the oleate of soda is sep- 

 arated, the gaduin remaining in solution. This is precipitated 

 from its solution by the addition of sulphuric acid. Gaduin 

 is a dark brown substance, brittle and pulverizable when dry, 

 without odor or taste, quite insoluble in water, and in great 

 measure soluble in ether and alcohol. It is insoluble in nitric 

 and muriatic acids, but is dissolved by sulphuric acid, giving 

 a blood-red color to the solution, from which it is precipitated 

 by water and the alkalies. It is soluble in alkaline solutions. 

 Chlorine decolorizes it. Its formula is C^ H^, O 9 . By boil- 

 ing in alcohol it is gradually converted into a blackish-brown 

 insoluble substance. Gaduin itself is yellow, but becomes 

 brown by exposure to the air. It has not been ascertained to 

 be in any degree connected with the virtues of the oil. It is 

 highly probable that the biliary principles associated with the 

 oil are concerned in its peculiar influences, as it is by their 

 presence mainly that this differs from other oils. It has been 

 thought that gaduin itself is of biliary origin. Some have 

 been disposed to ascribe the virtues of the oil to its iodine and 

 bromine, but these are in too small proportion for much effect, 

 and the oil has produced results which have never been ob- 

 tained from iodine or bromine. The presence of iodine can- 

 not be detected by the usual tests. It is necessary to convert 

 the oil into a soap, and to carbonize this before it will give 

 evidence of iodine. The proportion never exceeds 0.05 per 

 cent, or 1 part in 2,000. The oil is capable of dissolving a 

 larger proportion, and if any specimen contains more, there is 

 reason to suppose that it has been fraudulently added. 



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