THE PLANT AS HEALER 149 
chemically isolated principle, still less the synthesised 
product, may be much less successful in the hands of 
the clinician. Thus aloin is much more uncertain in 
its action than the crude drug aloes,’and the synthesised 
salicin compounds are very difficult, practically impos- 
sible, to purify from phenolic associates. 
‘It seems as though in many cases the total action of a 
drug is due to the interaction of several components, 
some known and some, it may be, unknown, This is 
paralleled by the reinforcement which seems to take 
place in mixtures from several plants having practically 
the same properties. Such mixtures have been proved 
to be more effective than a corresponding strength of 
any one, and they form a justification for old-fashioned 
multiple compounds, now fallen into disrepute in 
orthodox medicine. The explanation of phenomena 
of this kind will, no doubt, ultimately be found in the 
realm of Physical Chemistry, as it is very probably a 
question of solubility. 
It is as well, therefore, perhaps, that most vegetable 
drugs are still manufactured from the plant, and con- 
sequently there is a vast industry in medicinal plants. 
_Both medical men and herbalists use large quantities 
of— 
Balm Penny Royal 
Comfrey Rue 
Feverfew Southernwood 
Celandine Tansy 
Woodsage Wormwood 
Marsh Mallow Yarrow, etc. 
It must be remembered that while the tendency of 
orthodox modern medicine is to limit more and more 
the use of drugs to a few of the better known, there is 
