Human Calculi , 227 
N° 10. The brown mulberry part covered by N° 9. The 
three following are parts of one large, laminated calculus ; of 
which 
N° 11. Is the external lamina, of a brownifh yellow. 
N° 12. The central part, called the nucleus? of a pale 
orange colour. 
N Q 13. Some of the laminae, between the nucleus and the 
external coat, of a fparkling appearance. 
N° 14. A whitilh, porous, and eafily broken calculus. 
The experiments by fire explain the unequal accounts of 
authors, refpe&ing the component parts of calculi. 
In general, thofe which contain the largeft proportion of 
volatile parts were moft foluble in lixivium. 
The inlolubility of fome explains the want of fuccefs in 
feveral cafes, where lixivium, foap, and lime-water, have been 
given as remedies. 
The folubility of others, joined with the tefiimony of re- 
putable authors, and my own experience for near thirty years, 
confirm the falutary effects of lixivium in many cafes. 
It frequently happens, in fits of the gravel and ftone, that 
gravel or fmall pieces of calculi are difcharged, which Ihould 
be examined. 
If perfectly foluble in lixivium (Aq. kali puri J, the remedy 
is obvious ; if imperfectly, doubtful ; if infoluble, lixivium 
will only irritate, without benefit. 
I am, &c. 
T. LANE. 
Alderfgate-ftreet, 
March 10, I7Q1® 
H h 2 
