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XXIV. A Note upon the Anatomy of the Roots of Ophrydese. By John 

 LiNDLEY, Ph.D. F.R.S. 8f L.S., Professor of Botaiiy in University College. 



Read February 5th, 1839. 



IT is well known, that the substance imported from the Levant under the 

 name of Scilep, consists of the parboiled tubercles of certain Ophrydeous 

 plants, probably belonging- to the genus Orchis itself; but while writers are 

 agreed as to the source of Salep, there is so nuich difference among them, as 

 to the nature of the principle it contains, that it has appeared to me desirable 

 to ascertain whether anatomical examination would not decide the question 

 better than the ordinary methods of chemical investigation ; and the result 

 has justified my expectation. 



The following instances of difference in the statements of writers upon 

 Salep will serve to show how far we yet are from understanding the nature 

 of this very common substance. 



Berzelius says it contains very little gum and starch, but much vegetable 

 mucus (Pflanzenschleim). Caventou describes it as containing a substance 

 like Bassorine ; that is, a gummy principle differing from gum in being inso- 

 luble, only swelling up into a jelly, and from all varieties of starch by not 

 forming a blue compound with iodine. 



On the other hand, Guillemin says it is composed •' presqu' entièrement de 

 matière féculante" {Diet. Class, xv. 70.), a statement which I quote merely to 

 show the prevalent opinion of French writers on such subjects ; an opinion 

 which is by no means changed. Guibourt, who, in order to form a correct 

 idea of Salep, examined Orchis roots before they were prepared, declares that 

 they are composed "d'une grande quantité d'amidon" in grains the size of 

 wheat starch ; and he adds, that this starch is entirely filled by a pulpy mat- 

 ter, insoluble in cold water, but swelling and dividing very much in hot 



VOL. XVIII. 3 K 



