304 ON PLANTS IN RELATION TO ANIMALS. 
species, all of which are probably introduced from Asia. 
One species, the T. arvense, is common to our corn-fields, 
where, as in arable fields in the States, it has doubtless been 
introduced in foreign seeds. 
Its common name ofMithridate mustard “ was prefixed to 
it,” so we learn from Mrs. Lankester, " because Mithridate, 
King of Pontus, was a famous mediciner, who compounded 
poison-resisting draughts, and gave them to himself.” 
Its name of Penny-cress is due to the rounded flat seed- 
vessels. It is very nauseous to the taste, arising from the 
acidity of its juices, and when the herbage is crushed it gives 
out an odour resembling garlic, in which it resembles the 
common Jack-by-the-hedge, or sauce alone. 
The plant in question is of no value, though, perhaps, in 
older times it might have been esteemed on account of 
its strong smell; it is not now of any service, as not even 
the doctrine of signatures helps it to any position. 
It is, however, well that it should be destroyed, as an ill- 
flavoured weed which no animal will eat. 
5. Iberis amara (Bitter Candytuft ) is best known as a 
garden plant, as it is capable of establishing several varie¬ 
ties, remarkable for its increase in the size of its flowers, and 
for a variety of gay colouring. 
It is only found in corn-fields, and then but in a few 
counties. It is reputed as a bitter and purgative, though 
not now at all used. Cattle refuse to eat it, and therefore 
it can in the wild state be only considered in the light of a 
weed. 
6. Isatis tinctoria (Dyer's Woad ).—This is an exceed¬ 
ingly interesting plant, from its past history. Dr. Syme 
says of its localities as follows : 
“ In cultivated fields and in chalk-pits, but certainly not 
native, and scarcely even naturalised, except in chalk-pits 
near Guildford, Surrey.” 
We have, however, been accustomed to find it on an 
elevated knoll on the banks of the Severn, called the 
“ My the Tout,” a name which connects the plant with the 
Celtic inhabitants of our island, it will, therefore, be ex¬ 
pected that its history and folke-lore will be more than 
usually interesting, and as the following notes by Mrs. Lan¬ 
kester are so much to the point we cannot forbear quoting 
them. 
Dyer’s Woad. 
Pastel des Teinturiers, French. 
Fdrber- VTaid, German. 
“The history of woad as a British plant commences with 
