94 



CRUCIFEE.E. 



often deeply toothed or pinnatifid, the upper lanceolate, sparsely toothed. 

 Flowers small, in numerous racemes, forming a terminal panicle. 



Habitat. — Introduced from Europe and cultivated chiefly as a condi- 

 ment. Escaping from cultivation, it has become, to some extent, natural- 

 ized. It grows best in deep, rich, moist soil, and when once well estab- 

 lished is difficult to eradicate. 



Two strictly indigenous species of this genus, namely, N. palustre De 

 Candolle — Marsh-cress, and N. lacustre Gray — Lake-cress, possess properties 



similar to those described 

 above, but as they are sel- 

 dom, if ever, employed, their 

 description is omitted. 



Parts Used. — Water- cress, 

 the herb ; horseradish, the 

 leaves and root. Neither is 

 official. 



Constituents. — Water-cress 

 distilled with water yields a 

 volatile oil, probably identical 

 with volatile oil of mustard ; 

 horseradish, treated in like 

 manner, yields a similar oil, 

 having the same chemical 

 composition as volatile oil of 

 mustard, but a slightly differ- 

 ent odor. This oil does not 

 pre-exist in the plant, but is 

 formed during the process of 

 distillation, as is the case with 

 many other volatile oils. It is 

 intensely acrid and irritating. 

 Preparations. — None are 

 official. The expressed juice 

 of water-cress has been ad- 



Fig, lOS.-Nasturtium (cochlearia) Armoracia. min istered. Horseradish is 



generally employed in infusion, though there is an official (British Phar- 

 macopoeia) preparation, Spiritus armoracice compositus— compound spirit of 

 horseradish. 



Medical Properties and Uses. —Water-cress, though used chiefly as a 

 stimulating salad to sharpen the appetite and aid digestion, possesses mild 

 antiscorbutic properties, and is used in domestic practice as a" blood 

 purifier " in the spring of the year. It probably acts simply as a stimulant 

 to the functions of digestion and assimilation. Externally it is sometimes 

 employed as a counterirritant. Horseradish possesses properties similar to, 



