396 COMPOSITiE. 



LACTUCARIUM. 



LactucariuTYi, Lettuce Opium, Thridccce ;^ F. and G. Lactucarium. 



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, more 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 

 Auvergne 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 0])ium, was published in 1799.^ 



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

 Young, Anderson, Scudamore and others in Scotland, and by Bidault de 

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

 carium in Auvergne was commenced* by Aubergier, pharmacien of 

 Clermont-Ferrand, about 1841. 



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

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

 flowering, instantly exude a white milky juice. The stem, at first solid 

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

 30 fibro-vascular 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 single or double circle of thin-walled tubes, the cavities of 

 which contain dark brown masses of coagulated juice. In longitudinal 

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

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

 meter, correspond pretty regularly in position with the vascular bundles. 

 Each of the latter is also separated from the pith by a band or arch of 

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

 occur. 



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



^ The term Thridace is also applied to the Opium officinarum, extracted from the 



Extract of Lettuce. Papaver somni/erum or White Poppy of 



2 The authors of the French Codex of Linnseus.andthatprocuredfromtheZac^wca 

 1866 name as the source of lactucarium sativa or Common cultivated Lettuce of the 

 that form of the garden lettuce which has same author. — Transact, of the American 

 been called by De Candolle Zoc<«ca capitata. Philosophical Society, iv. ( 1 799) 387. 

 Maisch has obtained lactucarium from L. * Comptes Rendus, xv. (1842) 923. 

 elongata Muhl. i^Am. Journ. of Pharm. * Beautifully delineated by Hanstein in 

 1869. 148). the work referred to at p. 352, note 2 ; see 



3 Inquiry into the comparative effects of also Tr^cul, Ann. des Sciences nat. Bot. v. 



