530 CONVOLVULACEA. 
‘The central cane-like woody column of the root or stem when 
present is seen to be divided into four parts by four bands of 
parenchyma (medullary rays); it consists of large dotted vessels 
connected together by narrow portions of woody fibre. : 
The black nisot has exactly the same structure as the white. 
Chemical composition.—Turpeth resin consists of a small ~ 
quantity of soft resin soluble in ether, and of a substance in- 
soluble in ether, benzine, bisulphide of carbon and essential 
oils. Thissubstance has been named Turpethin (0%*H%°O"), 
and is present in the root to the extent of 4 per cent.; it has — 
been examined by Spirgatis, who describes it as a grey powder — 
having a powerfully irritant action upon the mucous membranes — 
of the mouth and nose, and being analogous in its reactions — 
with jalapin and convolvulin. Under the action of alkaline 
_ bases it is transformed into turpethic acid, and in the presence — 
of hydrochloric acid becomes converted into glucose and tur- 
petholic acid. (Zeitschr. der Chemie und Pharmacte, 1865.) 
Turpeth resin is supposed to have a resemblance in colour and — 
action to Turpeth mineral, an old name for basic sulphate of © 
mureury, 
Commerce.—The price of the drug i in Bombay is about Rs. 2 
_ per maund of 374 lbs, . 
IPOMAZA HEDERACEA, Jacq. 
 Fig.—Jacq. Icon., t. 36; Bentl. and Trim., t. 185. Syn— 
ha “ont Nil, Chois. \ 
-Throughout India. The seeds. 
ar.—Mirchai, Kéladana (Hind.), Nil-kolomi, Kéla- 
dav (Beng.), Kodi-kikkatan-virai, Jiriki-virai (Tam.), Jiriki- 
ttulu, Kolli-vittula (Tel.), Kéladana (Guz.), Nilapushpi- 
eh Mar.). The same vernacular names are often 7 
to the seeds of Clitorea ternatea, 
21S! >. —These hom do not appear to be | 
| Medica, “naeta the 
name ' i-nfl, 
