Filtration. In this process solids are separated from fluids by allowing 

 the latter to pass out through a porous diaphragm. 



Dessication. In this process the watery constituents of drugs are 

 got rid of by the aid of currents of either hot or cold air. 



Distillation. In this process volatile substances are separated from 

 non-volatile or less volatile by the aid of heat. The volatile substances 

 are passed over a cooled surface on which they condense and are collected. 



Pulverization. By this process the drug is reduced to a very finely 

 divided condition (or powder). The degree of fineness is determined by 

 the number of meshes to the linear inch of the finest sieve through which 

 the powder can pass. The sieves used contain 20, 40, 60, 80, 100 meshes 

 to an inch. The simplest method of pulverizing the drug is by means of a 

 mortar and pestle but in large pharmaceutical houses this end is usually 

 obtained by means of a mill. 



Trituration. This term may be used as synonymous with pulveri" 

 zation, but more commonly refers to an intimate mixing and powdering o^ 

 two drugs by means of a mortar and pestle or of a spatula. 



GALENICAL PREPARATIONS. 



The crude drugs are rarely suitable for administration to the patient 

 and in consequence are prepared by the pharmacist in various ways before 

 being dispensed. The methods by which they are prepared have been 

 defined above, but the forms in which they are dispensed are known by 

 various names descriptive of the form in which they are dispensed or of the 

 methods and solvents by which they are prepared and which must be known 

 by the physician. The less important terms are printed in italics. 



Official Preparations. 



Acetum, (Vinegar, e.g. Acetum Scillae) A solution of active principle 

 made by solution or maceration with acetic acid. 



Aqua, (Water) A solution of volatile substances in water, some are 

 simple solutions, such as Aqua Chloroformi, while others (Aqua Cinnamomi) 

 are prepared by distillation if made in accordance with the British Phar- 

 maccepia. In the colonies a pharmacist is allowed to make a Water con- 

 taining a volatile oil by first triturating the oil with calcium phosphate 

 and then suspending the triturate in water. The oil being very finely 

 divided remains suspended in the water. The Waters are very commonly 

 used in mixtures as flavoring vehicles for the administration of less pleasant 

 drugs. They are in some cases of value on account of their own phar- 

 macological action. 



Charta, (Paper, e.g. Charta Sinapis) A strip of cartridge paper smeared 

 with a preparation of an active drug. They are applied to the surface 

 of the body. 



Collodium, (Collodion, e.g. Collodium Flexile). A solution of Pyroxylin 

 in Ether and Alcohol, either alone or containing also some other drug in 



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