EXAMINATION OF VEGETABLE POWDERS 11 



lavender, marine blue, terra cotta, Pompeian red, canary red, Chinese 

 yellow, etc., are devoid of meaning to the uninitiated. 



Form and texture greatly modify the color. This is true of drugs 

 as well as of other substances. The same color on a rough and a 

 smooth surface will present a markedly different tone, the rough sur- 

 face producing a shade effect, hence the color will appear darker. In 

 the case of powdered drugs it will be noticed that fineness greatly 

 modifies the color, the finer powders producing tint effects as a rule. 

 In some instances a difference in fineness may even modify the quality 

 of the color entirely (licorice root) . 



We need scarcely urge the necessity of good illumination in the 

 inspection of powders. The color of the powder should be carefully 

 compared with the description given in some standard text-book. 

 In nearly every instance the student will find some slight deviations 

 in the color and consistency observed as compared with that given 

 in the book. An effort should be made to account for these differences. 

 The student should make careful drawings of the microscopic 

 structure of the powder. The value of this cannot be overestimated. 

 In order to make a correct drawing it is absolutely necessary to study 

 the powder carefully; furthermore, the act of making the drawing, 

 as well as the visualization of the drawing itself, will impress the 

 structural characters more firmly upon the mind. 



II. TACTILE SENSATIONS 



The sense of touch is the oldest of the senses in the order of evolu- 

 tion, and the other sense, as taste, smell, sight and hearing, are but 

 modifications or specializations of this primary sense. Touch, as it 

 applies to the examination of drugs, is a tactile sensation appreciated 

 by the hand and fingers, the tongue and mouth, rarely also the larynx. 

 The touch of fingers and hands conveys to the mind conceptions of 

 coarseness or fineness, fatty, oily or unctuous condition, crispness, of 

 moisture, dryness, mucilaginous condition, tendency to lumpiness ; 

 etc. In many instances the sense of touch is merely an aid to the 

 sense of sight that is, touch verifies or assists the visual judgment. 



The tactile sense of the fingers may be greatly increased in delicacy 

 by education and practice and by proper care. The most sensitive 

 parts of the fingers are the tips ; this sensitiveness is greatly enhanced 

 by cleanliness of hands and nails. The nails should be carefully and 

 evenly trimmed, but never very short, as that reduces sensitiveness. 

 The clean, trimmed, free portion of the nail amplifies or magnifies 

 the tactile sense by pressing upon the opposing delicate dermis when 



