This section is from the book "A Practitioner's Handbook Of Materia Medica And Therapeutics", by Thos. S. Blair. Also available from Amazon: A Practitioner's handbook of Materia Medica and Therapeutics.
U. S. P. Tinctures, by the recent revision, are much changed in strength. Potent tinctures are now made of 10 per cent strength, whereas the 1890 aconite was 35 per cent., belladonna I5 per cent., cannabis indica I5 per cent., cantharides 5 per cent., colchicum seed I5 per cent., digitalis I5 per cent., gelsemium I5 per cent., Hydrastis 20 per cent., hyoscyamus I5 per cent., lobelia 20 per cent., physostigma I5 per cent., sanguinaria I5 per cent., squill 15 per cent., stramonium 15 per cent., strophanthus 5 per cent., and veratrum 40 per cent.
Tinctures are frequently made by diluting a fluidextract, but the practice is not to be commended. The U. S. P. tinctures are to be preferred to the fluidextract in many instances, since they possess tire distinct advantage of an excess of solvent holding in solution the inert substances so liable to cause trouble with fluidextracts. Veratrum viride is an instance of this. Here we have a drug quite difficult to work. If the root is too recent, it forms with alcohol a slimy mess, while if it is tinctured in a perfectly dried state it does not possess the full drug value. To use the partially dried root in a fluidextract is not readily done to advantage, whereas a 10 per cent tincture carries the drug perfectly. The tendency of the U. S. P. Revision Committee is to eliminate tinctures so far as is possible, and where the tincture is retained there is usually very substantial data back of their decision.