180 
medullary rays. The dotted duds are almost invariably 
placed within these parenchymatous plates. They are nearly 
circular in form, though sometimes compressed radially, and, 
at others, concentrically ; and they vary in diameter from 
-j-Jpoth to x-oVoth of an inch, usually, however, being -5-g-g-th. 
Longitudinal cylindrical tracts of delicate parenchyma sur- 
round the pith, and occur also in various portions of the wood. 
In the latter situations, these tracts vary from -r^-oth to 
y-Lyth, and, in the former, from -^th to -—th of an inch in 
diameter . 1 
The cells of the medullary rays and of the concentric plates 
of parenchyma are filled with starch granules of moderate 
size (about 4 0 ' 0 0 th of an inch in greatest diameter) and of 
irregular oval forms, which seem identical in appearance with 
the starch granules in the non-indurated pith cells. 
The corky layer and cellular envelope of the bark are mode- 
rately developed. In the endophloeum the development of 
bast cells is very slight, only a few isolated bast cells being 
seen in cross-section. Immediately internal to these, how- 
ever, there is a distinct layer, about ygyyth of an inch thick, 
and three or four cells deep, of indurated parenchyma, the 
cells of which are small and of various shapes, and exhibit 
radiating canals. 
Strychnos Nux vomica . — The pith is only slightly indu- 
rated ; and, in the sections examined, its cells almost invari- 
ably contain starch granules — a very few nearly perfectly 
indurated cells are, however, present. These cells vary con- 
siderably in diameter, some being met with of f 0 V 0 th of an 
inch, and others of -g-t^th. The majority of the smaller cells 
occur at the circumference of the pith. 
The wood-cells are of the same character as those of akazga. 
The cylindrical tracts of delicate parenchyma are, however, 
larger, and much more numerous than those in akazga. 
The dotted ducts are also more numerous, and, in place of 
being arranged singly or in groups of two or three, they 
frequently occur in groups formed of radial lines of five or 
six. In consequence, apparently, of this great development 
in the number of the dotted ducts, the wood of nux vomica, is 
divided into much smaller masses than that of akazga . 2 
The general botanical characters of the akazga plant, the 
minute anatomy of its stem, the nature of its poisonous action, 
1 Similar tracts of parenchyma have been observed by Professor Oliver 
in Strychnos loxifera (Oliver “ On the Stem of Dicotyledons,” ‘ Nat. Hist. 
Review,’ vol. ii, 1862, p. 317). 
2 This structural character of nux vomica is apparent on simple inspec- 
tion of a cross section. 
