476 APPENDIX. 



be quite fresh and clean ; the leaves (as of scurvy-grass and wood-sorrel) 

 must be picked from their stalks, and the flowers must be deprived of their 

 calyx and peduncle, except in labiate flowers, (such as lavender,) in which 

 the calyx mnst not be removed. Moreover, in roses, the heel or claw,— the 

 small white end of the petals— must be cut off and thown away. They must 

 then be carefully pounded in a Wedgewood mortar, till they are reduced 

 to a pulpy mass, when the sugar should be added and the whole beaten 

 together till they are perfectly blended. The proportion of sugar employed 

 is, in general, thrice the weight of the vegetable substance ; but if re- 

 quired for immediate use, twice the weight is sufficient. Confections 

 should be put into earthen jars, carefully tied over with a piece of wet 

 bladder, and over that a covering of leather or stout paper. 



DECOCTIONS. 



Decoctions are solutions of the active constituents of vegetables obtained 

 by boiling. By this mode of preparation we obtain not merely the principles 

 soluble in water, but those which are only to be dissolved by continued heat. 

 The process is chiefly used for mucilaginous and bitter substances, and is 

 improper when the active principles of a plant are volatile, or consist chiefly of 

 extractive matter. The substances employed should be previously bruised or 

 sliced, and should be kept from the access of air as much as possible. The 

 operation should be performed over a clear fire in a covered vessel ; soft and 

 filtered water should be employed, and the ebullition should not be violent. 

 Woods, barks and roots require most boiling, and these ought in general to 

 be boiled down to one half; when these articles are combined with leaves 

 and stalks, the latter should be added towards the end of the process. De- 

 coctions should be strained while hot, and ought not to be made in large 

 quantities, as they will seldom keep for forty-eight hours. 



The proportion for decoctions is, for the generality of vegetable substances, 

 one ounce to a pint and a half of water, which should be reduced to a pint. 

 Where other proportions are required, they are noticed in this work under 

 the respective articles. 



DISTILLED WATERS. 



By distillation with water the odorous and volatile principles of plants are 

 to a considerable extent brought over. Waters are to be distilled from 

 dried plants in general, because fresh plants are not always to be pro- 

 cured ; but if the latter are used it must be in double the weight. 

 Delicate odorous flowers, however, should always be distilled in the recent 

 state. The first thing to be attended to in distillation is the proportion 

 of water necessary to prevent the plants from burning. The general 

 rule is to put nearly twice as much water in the still as you intend to draw 

 off; or as much as will be sufficient after tbe quantity required shall 

 have been drawn off, as will prevent the vegetables from being scorched ; 

 a little proof spirit is usually added. 



