Gn Dr. MARTIN’s CANCER POWDER. 215 
1. The ufe of cauftics in cancers and foul ulcers is very 
ancient, and univerfal. But I believe ar/enic to be the 
moft efficacious of any that has ever been ufed. It is the 
bafis of Plunkett’s and probab+y of Guy’s well known 
cancer powders. The great art of applying it fuccefs- 
fully, is to dilute and mix it in fuch a manner as to mi- 
tigate the violence of its ation. Dr. Martin’s compofiti- 
on was happily calculated for this purpofe. It gave lefs 
pain than the common or lunar cauftic. It excited a mode- 
rate inflammation, which feparated the morbid from the 
found parts, and promoted a plentiful afflux of humours to 
the fore during its application. It{feldom produced an efcar; 
hence it infinuated itfelf into the deepeft receffes of the 
cancers, and frequently feparated thefe fibres in an un- 
broken ftate which are generally called the roots of the 
cancer. Upon this account, I think, in an ulcerated can-= 
cer it is to be preferred to the knife. It has no action up- 
on the found fkin. This Dr. Hall proved by confining a 
{mall quantity of it upon his arm for many hours. In 
thofe cafes where Dr. Martin ufed it to extra@t cance- 
rous or fchirrous tumors that were not ulcerated, I have 
reafon to believe that he always broke the fkin with Spa- 
nifh flies. 
2. The arfenic ufed by the doGtor was the pure white 
arfenic. I fhould fuppofe from the examination I made 
of the powder with the eye, that the proportion of arfenic 
to the vegetable powder, could not be more than ,*, part 
of the whole compound. Ihave reafon to think that the 
doctor employed different vegetable fubftances at different 
times. The vegetable matter with which the arfenic was 
combined, in the powder which I ufed in my expe- 
riments, was probably nothing more than the powder 
of the root and berries of the folanum lethale, or deadly 
nightfhade. As the principal, and perhaps the only de- 
fign of the vegetable addition was to blunt the acti- 
vity of the arfenic, I fhould fuppofe that the fame propor- 
Ee 2 tion 
