94 



CRUCIFEE.E. 



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

 Flowers small, in numerous racemes, forming a terminal j)anicle. 



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. jjalustre De 

 CandoUe — Marsh-cress, and N. lacustre Gray — Lake-cress, possess proj^erties 



similar to those described 

 above, but as they are sel- 

 dom, if ever, employed, their 

 description is omitted. 



Palis Used. — Water- cress, 

 the herb ; horseradish, the 

 leaves and root. Neither is 

 official. 



Constituents. — Water-cress 

 distilled v/ith water yields a 

 volatile oil, probably identical 

 with volatile oil of mustard ; 

 horseradish, treated in like 

 manner, yields a similar oil, 

 ha\dng the same chemical 

 composition as volatile oil of 

 nnistard, 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 iiTitating. 

 Preparations. — None are 

 official. The expressed juice 

 of water-cress has been ad- 

 ministered. Horseradish is 

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

 macoiyoeia) preparation, Sjnritus armoracice eompositus — compound s^nrit 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 couuterirritant. Horseradish possesses properties similar to. 



Pig. 108.— Nastnrtinm (cochlearia) Armoracia. 



