[ 59 + 3 
putrified, or in powder ; and yet fome part will re- 
main, which it is very difficult to take out from the 
twifted canals, efpecially in thofe lponges of the tra - 
gos kind, fo hard to cleanfe. In a word, the blood 
or humours, which the ancients have obferved, is 
no other than the mucilage or juice of the fubftance 
of thefe worms. 
Dated at Guadaloupe, 
i March, 1757. 
LXXIX. Account of an Experiment , by which 
it appears , that Salt of Steel does not enter 
the LaEieal V ejfels ; with Retnarks . In a 
Letter to the Rev. Tho. Birch, D.D. Seer . 
R. S. By Edward Wright, M. D. 
S I R, 
Read Mar. 2, ^ I ^ H O’ iron is univerfally allowed to 
75 be one of the moil powerful me- 
dicines now in ufe, yet many phyficians obferving, 
that the faces of patients, who ufed it either in a 
metallic or faline form, were tinged of a black co- 
lour, have been led to think, that, in a metallic ftate, 
it could not be reduced into particles fine enough to 
be received by the latteal vefiels ; and if taken in a 
faline form, that it underwent a precipitation in the 
inteftines, by which, being reduced to an earth or 
calx, it was in like manner rendered incapable of 
making its way into the blood. But the accurate ex- 
periments, with which bignor Menghini has favoured 
3 the 
