400 . APOCYNACEM. 
closely followed by cessation of the respiration. According, to 
Fraser {T'rans. Royal Soc. Hd. xxiv.) oleander like digitalis, &c., 
produces at first irregularity and acceleration of the heart’s 
action, then a diminished frequency caused by protraction of 
the ventricular systole, and, finally, stoppage of the contractions 
by cessation of the dilation of the ventricles, which remain con- 
tracted, white and perfectly empty. | 7 
Description. —Roots crooked, bark thick, soft, external 
surface grey, corky, on young roots the corky layer is very 
thin, and the interior yellow colour of the bark is seen through it, 
inver surface yellow. The bark when cut or wounded.exudes 
a pale yellow latex, which is resinous and very sticky, Odour 
somewhat acrid. ‘Taste acrid and bitter. 
Microscopie structure.—In the bark of the roots the medul- 
dary rays are very numerous; their being loaded with yellow 
resinous juice makes them very conspicuous. The laticiferous 
vessels are numerous and generally 1 in groups of two, three, or 
more. The wood is yery porous, and abounds in large dotted 
vessels. Both bark and wood abound in starch. 
Chemical composition. —Mr. H. G. Greenish has extracted 
from the bark of V. odorum two bitter principles, one soluble 
in chloroform and little soluble in water, to which he has given 
the name Nertodorin, and another very soluble in water and 
‘insoluble 1 in n: Qblonoform, which he has named Neriodorein. Both 
of theses 
bstances are powerful heart-poisons. Neriodorein 
vis. rphous powder of a pale yellow colour, and very 
bitter taste, insoluble in petroleum spirit, ether, benzol, 
chloroform, salphide of carbon, amylic alcohol, and acetic ether, 
-but readily soluble in water and alcohol. It contains no nitro- 
-gen; a watery solution is neutral to test paper. Chloroform 
«partly separates it from its watery solution in the form of an 
-oily liquid. Chloroform and ether precipitate it from an _ 
_alcoholic solution in a floceulent condition. It is soluble in 
_glacial acetic acid, the evaporation of the solvent leaves a 
- yellow amorphous - varnish-like mass. Although the aqueous) 
pa through the dialyser it has not ee hess Sasol — 
