138 
DR. C. B. PLOWRIGHT ON WOAD AS A BLUE DTE. 
I. 
WOAD AS A BLUE DYE, WITH AN ACCOUNT OF 
ITS BIBLIOGRAPHY. 
By C. B. Plowright, M.D. 
Bead 25th April, 1900. 
“As blue as Wad ” is an old Norfolk saying applied by our grand- 
parents as occasion arose, but notably to badly washed linen, when 
the laundress sought to hide her inefficiency by an extra dose of 
the blue bag, or to an unfortunate ague-stricken patient in the cold 
stage. The excellent paper by Mr. E. Corder,* which appeared in 
our ‘Transactions’ for 28th October, 1890, has so thoroughly gone 
into the whole matter of East Anglian Woad culture and preparation 
that the present remarks must be regarded as quite supplemental 
to it, having been, in fact, inspired by it. Frequent visits have 
been made to the Parson Drove Woad Mill, and a long series of 
experiments conducted before the blue colour, the indigo in fact, 
in this Woad could be demonstrated. Curiously enough the subject 
has engaged the attention of Professor Beijerinckf of Delpht, and 
by his help the presence of indigo was easily shown in the fresh 
plant from Parson Drove. The blue colour of Woad is indigo, 
C 16 H 14 N 2 0 2 . The same substance chemically as that obtained from 
In dig of era tinctoria and Polygonum tindoria. There is this great 
difference however : in the last named plants it exists in a form 
which is easily extractable, whereas in Woad it exists in a condition 
which is the very reverse. 
In 1855, Dr. E. Schunck,j; in an exhaustive paper on the 
* Corder E. Trans. Norfolk and Norwich Nat. Soc., 1890, vol. v. p. 144. 
t Beijerinck Prof. M. W. “ On the formation of Indigo from Woad.” 
‘Koninkijke Akademie van Wetenschappen te Amsterdam,’ 1899, p. 120. 
30th Sept. 
I Schunck Dr. E. “ On the formation of Indigo from Woad.” ‘ Philo- 
sophical Magazine,’ vol. x. p. 74, 1855. 
