248 
HUMAN GALL STONE. 
of 100° Far., change to a dark brown color, and emit an 
urinous odor — at a still higher temperature they liquify, be- 
come oily, and assume on cooling a brittle mass ; when 
heated still higher, they ignite, burning with a white flame, 
and much smoke, leaving a black residuum resembling 
animal charcoal. This residuum effervesces with chloro- 
hydric and nitric acids, and with the formep is almost en- 
tirely soluble in distilled water, yielding an agreeable and 
clear solution; with the latter acid, however, the solution is 
insipid. 
From the above, and other experiments, we derive the 
following conclusions. 
1st. That the crust of these calculi is composed of a 
peculiar coloring material, called by Berzelius, " bilifulvin," 
which, we may add, is found in small quantities in a healthy 
person, but accumulates in a state of disease, as in jaun- 
dice, so as to produce solid masses. It is insoluble in alcohol 
and ether, in the strong acids, volatile oils and spirits of 
turpentine ; but with pure potassa and soda, and some of 
their salts, makes a solution of a blue color. 
2d. That this "bilifulvin" is converted into the green co- 
loring matter, which is present in healthy bile by the ab- 
sorption of oxygen, — its solution in potassa being changed 
from a blue by this means. 
3d. That a peculiar fatty matter enters largely into their 
composition, called " cholesterine," which is insoluble in 
water, fusible at 279°, and volatizable in close vessels with- 
out change; its formula being C 36 H 30 0. It isdisolved by 
boiling ether and alcohol, which on cooling deposits it in 
brilliant plates cf a pearly lustre, — it is not saponified or 
altered by caustic .alkalies, but by a treatment with nitric 
acid is converted into cholesteric acid. C 26 H 20 N0 12 . 
4th. And lastly. That they are exceedingly analogous to 
the bezoar stones of the herbivirous animals, if they are not 
identical in every particular of their composition. 
Philadelphia, December 20, 1844. 
