TIIR JOURNAL OF PHARMACOLOGY. 



259 



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Powdered Belladonna. — S, starch ; Par. parenchyma, long view ; Pr, parenchyma, in cross section ; 

 Pt. Duct, pored duct ; RD, reticulated duct ; SV, spiral ducts ; Tr, tracheids ; F, fibers ; CT, corky 

 tissue , O, tissue from phloem. 



The parenchymalic cells of the cortex form a large part of the powder. 

 The" cells are usually ample, ranging from 60 to 100 micra. They are 

 comparatively thin-walled and are usually filled with starch grains. 

 Some fewjspecial cells of the parenchymatic sheath contain the acicular 

 crystals of calcium oxalate. 



The remaining elements of the powder present an interesting series -of 

 gradationsun cell structure. In some works they are all called tracheids, 

 yet there would seem to be enough characters to differentiate wood-fiber- 

 like tracheids, true tracheids and vessel-like tracheids. Schneider makes 

 at least six kinds of tracheids in his description (Journal of Pharma- 

 cology, 4, 1897, p. 3). 



The most characteristic cell forms are : (1) Vessel-like tracheids, having 

 large openings, usually at the end of diagonal cross walls ; these are 



