Observations on the effect of madder root on the bones of animals / [Benjamin Gibson].

  • Gibson, Benjamin, 1774-1812.
Date:
1805
Catalogue details

Licence: Public Domain Mark

Credit: Observations on the effect of madder root on the bones of animals / [Benjamin Gibson]. Source: Wellcome Collection.

    13/22 page 11
    mg of this property of madder, he says,* c< We C4 have, in the fact before us, a beautiful ex- 6< ample of a particular case of chemical at- w traction ; such as in numberless instances, “ is observed to take place, between the co~ “ louring particles of both animal and ve- <c getable substances, and various other bodies, “ especially earths and earthy salts, and oxydes “ of metals. So strong is the affinity of the cc colouring matter to these bodies, that it is frequently observed to quit the menstruum, <c in which it may chance to be dissolved, to “ unite with them : they, in consequence of “ its union, acquiring a particular tinge, ** whilst the menstruum is proportionably de- % “ prived of colour.-From this principle, “ this mutual attraction, is deduced the va- “ rious use of those bodies as mordents, as “ they are called, intermedia, or means for “ fixing the colours in dying or staining thread <c or cloth, whether it be composed of ani- “ mal or vegetable materials. Upon the same principle depends the preparation of “ those pigments, known to painters under “ the name of lakes; these are truly precipi- “ tates of the colouring matter, in combina- * See Dr. Blake’s inaugural Dissertation. De dentium jforraatione. p. 119.—*1793.
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