Saliva or oral fluid based tests are becoming more popular because of the convenience of the method and the fact that there is no chance for these tests to be adulterated.
They are occasionally adulterated with the leaves of Inula Conyza, ploughman's spikenard, which may be distinguished by their greater roughness, their less divided margins, and their odour when rubbed; also with the leaves of Symphytum officinale, comfrey, and of Verbascum Thapsus, great mullein, which unlike those of the foxglove have woolly upper and under surfaces.
The rhizome of Acorus Calamus is sometimes adulterated with that of Iris Pseudacorus, which, however, is distinguishable by its lack of odour, a stringent taste and dark colour.
Amongst its chief recommendations were those relating to amendments in the Agricultural Holdings Acts, and to tithe rentcharge, railway rates, damage by game, sale of adulterated products, and sale of imported goods (meat, for example) as home produce.
One species was a liquid, which was apt to be adulterated; but when pure it had the property of blackening when added to pomegranate juice.