ACONITE. 141 



The parenchyma is usually thin- walled, inclined to be 

 regular, and filled with starch grains ; the parenchyma tic 

 meshes range from 60 to 100 microns. 



ACONITE. 



Aconite is the tuber of Aconitum napellus, L., natural 

 order RanunculacecB, and grows pretty widely over the 

 northern hemisphere. It is extensively cultivated in 

 Germany, France, England, Switzerland, and India. 

 The tuber should be gathered in winter or early spring 

 — in some climates October seems the best month for 

 collection — from plants over one year of age. 



Powder. — The pow^der in bulk is brownish-gray and 

 has the peculiar taste, followed by tingling, characteristic 

 of the drug. Microscopically the following constituents 

 are recognizable in powder No. 60: Starch, parenchy- 

 ma tic tissue, cork cells, stone cells, endoderm cells, ducts, 

 tracheids — sometimes a few wood fibres and also a few 

 epidermal hairs*. 



The starch is made up of grains which are mainly 

 compound, growing in twos or threes, though often in 

 groups of four, occasionally in groups of eight. The 

 hilum is usually centric, mostly simple, sometimes 

 fissured ; concentric markings may be made out in some 

 of the numerous single grains. By polarized light the 

 cross is broad and distinct, its arms at right angles. The 

 average diameter of the single grains varies from 5 to 15, 

 the compound grains from 10 to 20 microns. The starches 

 of the other species of aconite are in the main similar; 

 that of A. ferox examined showed fewer compound 

 clusters, and the polarization cross was less distinct. 

 A. Japonicum had uniformly larger grains, the single 

 grains being often twice the size of A. napellus, and the 

 concentric markings much more distinct. The polari- 

 zation cross was indistinct in specimens examined. 



Stone cells are among the most characteristic features 



