70 VEGETABLE DRUGS WITHOUT ORGANIC STRUCTURE. 



The oil is transparent and yellowish, specific gravity 

 0.910 to 0.940, and yields among other products of dis- 

 tillation a sesquiterpene (Cadinene, C^fi^^) between 270° 

 and 280° C. and d-pinene between 160° and i6i°C. 



AMMONIACUM. AMMONIAC. 



Ammoniacum is a gum resin derived from the stems of 

 Dorema Ammoniacum, D. Don., a forest plant of Persia. 

 Other species of Dorema yield similar products. 



The plant has an abundant supply of milky juice which 

 exudes spontaneously and hardens in variously shaped 

 masses. Fine tears, varying in size from 2 to 5 mm. up 

 to the size of a hazelnut, are obtained from insect punc- 

 tured wounds,* while the so-called ammoniacum amyg- 

 daloides is obtained from the root of the plant. 



The resin is found in special secretory passages similar 

 to those found in asaf oetida and galbanum. In ammoni- 

 acum they lie in contact with the vessel bundles. 



Lump ammoniacum and Tear ammoniacum occur in 

 commerce. The former consists of miscellaneous masses 

 of debris of sticks, stones, etc., with pressed together tear- 

 like masses. 



Tear ammoniacum is made up of large tear-like granules. 

 These granules vary greatly in size, from small bird-shot 

 to larger nut-shaped masses. They are generally trans- 

 lucent, whitish to yellowish or brownish. Internally they 

 show a waxy lustre in fracture. At ordinary temperatures 

 the granules are wax-like or sticky, sometimes running 

 together in viscid masses. In the cold the ammoniacum 

 is brittle. The taste is sharp and bitter, later aromatic. 

 The odor is peculiar and aromatic, distinct from gal- 

 banum, but by no means as unpleasant as that of asaf oetida. 



Microscopical. — Under the microscope ammoniacum 

 shows as a gummy, homogeneous ground mass in which 

 small kernels and droplets are intermingled. Small 



* Hart: Tr. Linnsean Society XVI, 1833, p. 605. 



