THE PRINCIPLES OF BOTANY. 
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plants were used as medicines upon the most fanciful assump¬ 
tions ; hence the doctrine of signatures which prompted the 
use of coltsfoot and common lungwort in coughs and lung 
diseases, on account of the white blotches on their leaves, 
supposed to simulate the appearance of slices of the lung, 
and therefore to miraculously or mercifully point to its uses 
as a cure in the disease of that organ. 
• ^ 
Take, again, the curiously-formed leaf of the navelwort, 
which, from a depression in the centre of the leaf not unlike 
the umbilical pit in the human stomach, was formerly, and 
is still, employed by the rustics, both as an internal medicine 
and an ointment for children supposed to be afflicted with 
weak stomachs. 
We recollect once, in Wiltshire, as we were gathering 
some specimens of the Cotyledon umbilicus (navelwort) for 
our herbarium, we were set upon by a couple of ancient 
females, who told us, in not overpolite terms, that we were 
doing mischief in destroying the plant, as it was a great 
deal more useful to the world than ourself was likely to be. 
Not to pursue this subject too far, we may point to colour 
as being held to be an indication of medicinal value; thus, 
saffron for skin diseases, fevers, eruptive and otherwise, as 
making people look yellow and sickly, is a common adjunct 
to remedies in such cases; and yellow Barbary bark is a 
rustic favourite in jaundice, both for man and the inferior 
animals, as is also turmeric as an adjunct in a cow’s drench 
for yellows. 
In the present day, however, though some of these may be 
employed in the dispensary, more as a colouring matter than 
for any other purpose, they are not relied upon as they once 
were ; but, instead of all this, plants are studied, not only as 
regards their anatomical details, as teaching us to classify 
and arrange them, but also their nature and composition, is 
made out by the chemist with the utmost exactitude so that 
the philosophy—not the guessing—of their action is known 
both to the physiologist and the therapeutist. 
Still, that botany is not enough studied in the human school, 
and certainly much less so in the veterinarian school, may be 
concluded from the fact that few medical men go beyond the 
Pharmacopoeia in the vegetable remedies they employ; and 
though the cow-leech has even a wider range of vegetable 
remedies, these are for the most part employed upon the 
pious doctrine of signatures. 
But if we look a little deeper into the subject, we shall 
find that a knowledge of plants may be expected to lead to 
the settlement of some important questions which at present 
