59 



be especially remembered. 2. They are so concentrated that less is 

 required for action, and 3. They keep better than tinctures and some 

 improve with age. 



With few exceptions, the fluidextracts of the Pharmacopoeia 

 may be classified according to the menstrua used in the extraction 

 of the drugs and the process of manufacture employed, but there 

 are several drugs which require special manipulation to make satis- 

 factory preparations and for them definite formulas have been de- 

 vised and are printed in full in the text. The formulas for the other 

 fiuidextracts correspond to one of the following types : 



Type Process A. In this class are included those fluidextracts 

 that are made with a menstruum of alcohol or a mixture of alcohol 

 and water by the usual process of percolation. 



Type Process B. In this group are included those fiuidextracts 

 in which glycerin or an acid is used in the extraction and two men- 

 strua are successively employed. The first menstruum contains the 

 acid or glycerin in definite proportion to the amount of drug while 

 the second consists of a mixture of alcohol and water intended for 

 completing the exhaustion of the drug. 



Type Process C. This is the process of fractional or divided 

 percolation (reper eolation). It is especially recommended for 

 drugs containing volatile ingredients, or constituents injured by 

 heat, but may be used as an alternative process in the formulas in 

 which Type Process A. is directed. 



Type Process D. In this class are included those fiuidextracts 

 in which extraction is effected by infusion and percolation with boil- 

 ing water, alcohol being added to the concentrated liquid as a pre- 

 servative. 



In the preparation of fiuidextracts by either process. A, B, or 

 C the rate of percolation must be perfectly controlled and, for the 

 quantities directed in the formulas of the Pharmacopoeia, (1000.0 

 Gms.) the rate of flow should not exceed ten- drops per minute, 

 until the reserved percolate is collected and twenty drops per min- 

 ute thereafter. 



Directions for the different Type Processes. 



Type Process A. Moisten required amount of the powdered 

 drug with a sufficient amount of the prescribed menstruum to ren- 



