[Footnote: Read at the meeting of the American Pharmaceutical
Association held at Niagara Falls. 1882.]
By Prof. P. W. BEDFORD.
The object of this query can be but one, namely, to inquire whether the
wood creosote offered for sale is a pure article, or not; and if not,
what is the impurity present?
The relative commercial value of the articles sold as coal tar creosote
and wood creosote disposes of the question as to the latter being
present in the former article, and we are quite certain that the cheap
variety is nothing more or less than a phenol or carbolic acid. Wood
creosote, it has been frequently stated, is adulterated with coal tar
creosote, or phenol. The object of my experiments has been to prove the
identity of wood creosote and its freedom from phenol. The following
tests are laid down in various works as conclusive evidence of its
purity, and each has been fully tried with the several samples of wood
creosote to prove their identity and purity, and also with phenol, sold
as commercial creosote or coal tar creosote, and for comparison with
mixtures of the two, that even small percentages of admixture might be
identified, should such exist in the wood creosote of the market.
The following tests were used:
1. Equal volumes of anhydrous glycerine and wood creosote make a turbid
mixture, separating on standing. _Phenol dissolves_. If three volumes
of water be added, the separation of the wood creosote is immediate.
_Phenol remains in permanent solution_.
2. One volume of wood creosote added to two volumes of glycerine; the
former is not dissolved, but separates on standing. _Phenol dissolves_.
3. Three parts of a mixture containing 75 per cent, of glycerine and
25 of water to 1 part of wood creosote show no increase of volume of
glycerine, and wood creosote separates. _Phenol dissolves, and forms
a clear mixture_. Were any phenol present in the wood creosote, the
increase in the volume of the glycerine solution, if in a graduated
tube, would distinctly indicate the percentage of phenol present.
4. Solubility in benzine. Wood creosote entirely soluble. _Phenol is
insoluble_.
5. A 1 per cent, solution of wood creosote. Take of this 10 cubic
centimeters, add 1 drop of a test solution of ferric chloride; an
evanescent blue color is formed, passing quickly into a red color.
_Phenol gives a permanent blue color_.
6. Collodion or albumen with an equal bulk of wood creosote makes a
perfect mixture without coagulation. _Phenol at once coagulates into a
more or less firm mass or clot_.
7. Bromine solution with wood creosote gives a reddish brown
precipitate. _Phenol gives a white precipitate_.
All tests enumerated above were repeatedly tried with four samples of
wood creosote sold as such; one a sample of Morson's, one of Merck's,
one evidently of German origin, but bearing the label and capsule of an
American manufacturer, and one of unknown origin, but sold as beech-wood
creosote (German), and each proved to be _pure wood creosote_.
Two samples of commercial creosote which, from the low cost, were known
to be of coal tar origin gave the negative tests, showing that they were
phenol.
Corroborative experiments were made by mixing 10 to 20 per cent, of
phenol with samples of the beechwood creosote, but in every case each of
the tests named showed the presence of the phenol.
The writer on other occasions applied single tests (the collodion test)
to samples of beechwood creosote that he had an opportunity of procuring
small specimens of, and satisfied himself that they were pure. The
conclusion is that the wood creosote of the market of the present time
is in abundant supply, is of unexceptionable quality, and reasonable in
price, so that there is no excuse for the substitution of the phenol
commonly sold for it. When it is directed for use for internal
administration (the medicinal effect being entirely dissimilar), wood
creosote only should be dispensed.
The general sales of creosote by the pharmacist are in small quantities
as a toothache remedy, and phenol has the power of coagulating albumen,
which effectually relieves the suffering. Wood creosote does not
coagulate albumen, and is, therefore, not as serviceable. This is,
perhaps, the reason that it has become, in a great measure, supplanted
in general sale by the coal tar creosote, to say nothing of the argument
of a lower cost.
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