244 PLANT ORGANS OR PARTS OF PLANTS. 



cotyledons only. Hesse also found a cholesterin-like 

 substance, physosterin. 



NUX VOMICA. 



Nux Vomica is the dried seed of Strychnos Nux Vomica, 

 L., a small tree, indigenous to India and occurring also in 

 Ceylon, Siam, and northern Australia. 



Description. — Dried Nux Vomica seeds are round or 

 disk-shaped, and flattened but a little depressed on one 

 side, and flattened on the other. They vary from 2 to 2.5 

 cm. in diameter and 0.33 to 0.5 cm. in thickness, and are 

 grayish in color. A number of closely appressed hairs 

 radiate from the centre to the circumference. The edge 

 is rounded or acute and at one point there is a promi- 

 nence, the micropyle. The hilum is in the centre, and 

 may be recognized by the scar left by the funicle. The 

 seeds are almost odorless, but have an intense bitter taste. 



Histology. — A thin epidermis covers the entirely gray 

 endosperm. 



The epidermis cells are thick- walled, deeply pored, 

 side walls swollen. Each epidermis cell has a long, 

 free papillose round-pointed hair, i mm. long, sharply 

 inclined. 



Beneath the epidermis there are a number of large 

 cells with dark-brown walls. 



On the outer surface of the endosperm is a layer of 

 small cells whose side walls are perpendicular to the 

 surface. These walls swell but slightly in water. The 

 layers immediately beneath swell markedly on being 

 placed in water. 



The layer of cellulose immediately surrounding the 

 lumen is apt to be more highly refractive than the sur- 

 rounding layers. The membrane of the cells is completely 

 perforated by a few fine punctures. The membranes 

 show the reaction of cellulose. In the interior of the 

 endosperm cells are aleurone grains with crystalloids very 



