214. On Dr. MARTIN’s CANCER POWDER. 
‘ 
the doctor’s powder, partly with a view of applying it to 
a cancerous fore which then offered, and partly with a 
view of examining it more minutely than I had been able 
to do during the doétor’s life. Upon throwing the pow- 
der, which was of a brown colour, upon a piece of white 
paper, I perceived diftin@ly a number of white particles 
{cattered through it. I fufpected at firft that they were 
corrofive fublimate, but the ufual tefts of that metallic fale 
foon convinced me that I was miftaken. Recolle@ing 
that arfenic was the bafis of moft of the celebrated cancer 
powders that have been ufed in the world, I had recourfe 
to the tefts for dete€ting it. Upon fprinkling a {mall 
quantity of the powder upon fome coals of fire, it emitted 
the garlic {mell fo perceptibly as to be known by feveral 
perfons whom I called into the room where I made the 
experiment, and who knew nothing of the obje& of my 
enquiries. After this with fome difficulty I picked out 
about three-or four grains of the white powder, and bound 
them between two pieces of copper, which I threw into the 
fire. After the copper pieces became red hot, I took them 
out of the fire, and when they had cooled, difcovered an evi- 
dent whitenefs imparted to both of them. One of the 
pieces afterwards looked like dull filver. Thefe two-tefts 
have generally been thought fufficient to diftinguifh the 
prefence of arfenic in any bodies, but I made ufe of a third, 
which has lately been communicated to the world by Mr. 
Bergman, and which is fuppofed to be in all cafes infal- 
lible. 
I infufed a {mall quantity of the powder in a folution of 
a vegetable alkali in water for a few hours, and then poured 
it upon a folution of blue vitriol in water. The colour of 
the vitriol was immediately changed to a beautiful green, 
and afterwards precipitated. 
I fhall clofe this paper with a few remarks upon this 
powder, and upon the cure of cancers and foul ulcers of 
all kinds. 
The 
