656 ORCHIDACE^.. 



German salep is more translucent and gummy-looking, and has the 

 aspect of being more trimmed and prepared. 



Microscopic Structure — ^The fresh tuber exhibits on transverse 

 section a few outer rows of thin-walled cells rich in starch. These are 

 followed by parenchyme of elongated colourless cells likewise containing 

 starch, and isolated bundles of acicular crystals of oxalate of calcium. 

 In this parenchyme, there are numerous larger cells filled with homo- 

 genous mucihige. Small vascular bundles are irregularly scattered 

 throughout the tuber. In Orchis mascula and 0. latifolia the starch 

 grains are nearly globular, and about 25 mkm. in diameter. In dried 

 salep the cell-walls are distorted and the starch grains agglomerated. 



Chemical Composition — The most important constituent of salep 

 is a sort of mucilage, the proportions of which according to Dragendorff 

 (18C5) amounts to 48 per cent. ; but it is doubtless subject to great 

 variation. Salep yields this mucilage to cold water, forming a solution 

 which is turned blue by iodine, and mixes clearly with neutral acetate 

 of lead like gum arable. On addition of ammonia, an abundant precip- 

 itate is formed. Mucilage of salep precipitated by alcohol and then 

 dried, is coloured violet or blue, if moistened with a solution of iodine 

 in iodide of potassium. The dry mucilage is readily soluble in ammon- 

 iacal solution of oxide of copper ; when boiled with nitric acid, oxalic, 

 but not mucic acid is produced. In these two respects, the mucilage of 

 salep agrees with cellulose, rather than with gum arable. In the large 

 cells in which it is contained, it does not exhibit any stratification, so 

 that its formation does not appear due to a metamorphosis of the cell- 

 wall itself. Mucilage of salep contains some nitrogen and inorganic 

 matter, of which it is with difficulty deprived by repeated precipitation 

 by alcohol. 



It is to the mucilage just described that salep chiefly owes its power 

 of forming with even 40 parts of water a thick jelly, which becomes 

 still thicker on addition of magnesia or borax. The starch however 

 assists in the formation of this jelly ; yet its amount is very small, or 

 even nil in the tuber bearing the flowering stem, whereas the young 

 lateral tuber abounds in it. The starch so deposited is evidently con- 

 sumed in the subsequent period of vegetation, thus explaining the fact 

 that tubers are found, the decoction of which is not rendered blue by 

 iodine. Salep contains also sugar and albumin, and when fresh, a trace 

 of volatile oil. Dried at 110" C., it yields 2 per cent, of ash, consisting 

 chiefly of phosphates and chlorides of potassium and calcium (Dragen- 

 dorff"). 



Commerce — The shipments of salep from Smyrna are about 5000 

 okkas (one okka equal to 283"21b. avdp.=rl28'5 kilogrammes) annually. 



Uses — Salep possesses no medicinal powers; but from its property 

 of forming a jelly with a large proportion of water, it has come to be 

 regarded as highly nutritious, — a popular notion in which we do not 

 concur. A decoction flavoured with sugar and spice, or wine, is an 

 agreeable drink for invalids, but is not much used in England.^ 



^As powdered salep is difficult to mix spirit of wine, tlieu adding the water stid- 



with water, many persons fail in preparing denly and boiling the mixture. The pro- 



this decoction ; but it may be easily man- portions are powdered salep 1 drachm, 



aged by first stirring the salep with a little spirit 1| fluid drachms, water \ a pint. 



