396 COMPOSITiE. 



LACTUCARIUM. 



lum, Letmce Ovtum. 



Botanical Origin — The species of Lactuca from which lactucarium 

 is obtained, are three or four in number, namely 



1. Lactuca virosa L., described in the foregoing article. 



2. L. Scariola L., a plant very nearly allied to the preceding and 

 perhaps a variety of it, but having the foliage less abundant, move glau- 

 cous, leaves more sharply lobed, much more erect and almost parallel 

 with the stem. It has the same geographical range as L. virosa. 



3. L. altissima Bieb., a native of the Caucasus, now cultivated in 

 Auyergne in France for yielding lactucarium. It is a gigantic herb, 

 having when cultivated a height of 9 feet and a stem 1^ inches in 

 diameter. Prof G. Planchon believes it to be a mere variety of L. 

 Scariola L. 



4. L. sativa L., the common Garden Lettuce.^ 



^ History— Dr. Coxe of Philadelphia was the first to suggest that the 

 juice of the lettuce, collected in the same manner as opium is collected 

 from the poppy, might be usefully employed in medicine. The result of 

 his experiments on the juice which he thus obtained from the garden 

 lettuce (L. sativa L.), and called Lettuce Opium, was published in 1799.^ 

 The experiments of Coxe were continued some years later by Duncan, 

 1 oung, Anderson, Scudamore and others in Scotland, and by Bidault de 

 Vdhers and numerous observers in France. The production of lactu- 

 canum in Auvergne was commenced" by Aubergier, pharmacien of 

 Clermont-Ferrand, about 1841. 



Secretion— All the green parts of the plant are traversed by a 

 system of vessels, which when wounded, especially during the period of 

 Ilowenng, mstantly exude a white milky juice. The stem, at first solid 

 and fleshy but subsequently hollow, owes its rigidity to a circle of about 

 A + ,i;^^-J^scular bundles, each of which includes a cylinder of cambium. 

 At the boundary between this tissue and the primary cortical paren- 

 chyme, IS situated the system of milk- vessels, exhibiting on transverse 

 section a smgle or double circle of thin-walled tubes, the cavities o^ 

 Which contain dark brown masses of coagulated juice. In longitudinal 

 section, they appear branched and transversely bound together, as m the 

 milk-vessels of taraxacum. The larger of these tubes, 35 mkm. m dia- 

 meter, correspond prettv remilarlv in r,n^\h\r.r. wUl^ fliA vascular bundles. 



V i y^-^^i'^uyj. pretty regularly m position with the vascuiai uuu>.^- 

 ii^ach ot the latter is also separated from the pith by a band or arcli o 



cambium, m the circumference of which isolated smaller milk-vessels 

 occur. 



The system of milk-vessels^ is therefore double, belonging to the 



' The aut W f ,^ ^ ^ ^ Papaver somniferum or W^''f\Ctacm<^ 



18G6 name art>,f * '' ^'"f,^ ^°'^'^ ^^ Linna^u s, an dtlmt procured from he ij^^^ 

 that fom of t\. T^%\^^ lactucarium sativa or C'omwo/cw/in-a/.^ /«"''f ^i,.;,, 



Maisch hi i£!i 'f ?"!^«'''."^«^«i>'<"««- PhiloHorhkal Society, iv. (1799 )387- 

 e?o,,i,ato Muhl m1 ^f^^^^^^ra^ from L. * Comptes Rendus, xv. (1842) 923. ; .^ 



1869 148) ^' ^ ""• '^°""'- of Pharvi. » Beautifully delineated by Hanstm ^^^ 



* Inquiry intn tV,o „^ . • the work referred to at p. 352, n ' ^. 



4 iry into the comparative eflfecta of also Tr^cul, Ann. des Scievces nat. m- 



