422 LATEX 



but the colour changes by exposure to a dull brown, the drug becoming 

 at the same time hard. They possess a strong characteristic odour, 

 different from but recalling that of opium, and a bitter taste. 



Lactucarium is tough and difficult to powder. Boiled in water it 

 softens to a plastic mass, but only very little of it is soluble. The 

 cooled and filtered liquid should not be coloured blue by iodine, 

 indicating the absence of starch, which has been found in factitious 

 lactucarium, but, as Composite plants contain no starch, this should 

 not be present in the genuine drug. Lactucarium is only partially 

 soluble in alcohol and ether. 



Constituents. It appears doubtful whether lactucarium possesses 

 any particular therapeutic action, although it has been used as a 

 sedative. Lactucin, lactucic acid (crystalline), and lactucopicrin 

 (amorphous) are three bitter principles, the re-examination of which 

 is to be desired. Lactucerin (lactucone), constituting about one-half 

 of the drug, and extracted from it by boiling alcohol, is a crystalline, 

 tasteless, inert, waxy substance, yielding by saponification acetic acid 

 and lactucol (or, according to Hesse, a- and /3-lactucerol). 



In addition to these constituents, that are apparently peculiar to 

 lactucarium, various other substances commonly found in the latex 

 of plants have been detected, such as caoutchouc, albumen, mannite, 

 certain inorganic substances, &c. 



The alkaloid hyoscyamine, which Dymond detected in both wild 

 and cultivated lettuce, especially when the flowering stage is reached, 

 and to which possibly any sedative action of the fresh plant might be 

 due, could not be found in lactucarium. 



Uses. Lactucarium has been used as a sedative, but is now not 

 much employed. 



GUTTAPERCHA 



Source, &C. Guttapercha is obtained from the latex of several 

 species of Palaquium and Payena (N.O. Sapotacece) , the principal being 

 P. oblongifolium, Burck, P. borneense, Burck, P. Leerii, Burck, and 

 P. Treubii, Burck, all of which are stately trees indigenous to the 

 Malay Archipelago. They contain in the bast, as well as in the cortical 

 parenchyma of the stem, extending into the mesophyll of the 

 leaves, numerous superposed, elongated laticiferous cells which are filled 

 with a granular latex. It is this latex that forms, when properly 

 prepared, guttapercha. To that end the trees with a trunk about 

 30 cm. in diameter are felled, the branches stripped off, and transverse 

 or oblique channels cut in the bark. Into these the latex is discharged, 

 and in them it coagulates. This coagulation is apparently due to 

 the coagulation of an albumin in the latex by which the separate 

 particles of guttapercha are entangled and retained. The coagulated 



