On the Immediate Principles of Human Ezcrements. 311 
acid, of the precipitate induced by adding milk of lime to the cold 
and clear alcoholic extract of feeces, after the separation of the above- 
described deposits. 
In the month of December 1855, I had an opportunity of noticing 
that during a cold night, when the temperature falls below the 
freezing-point, excretine crystallizes readily and in large quantity in 
the clear alcoholic extract of feeces ; this method I employed as often 
as possible, to prepare enough excretine for its chemical analysis ; 
but the cold weather not lasting long enough, and this season having 
been remarkably mild, I was compelled to adopt a modification of 
the process by milk of lime, described in my former communication. 
Having prepared a sufficient quantity of excretine, partly by the 
action of cold, and partly by means of milk of lime, the chemical 
composition of this substance was now determined. A qualitative 
analysis showed it to consist of carbon, hydrogen, sulphur and 
oxygen* ; there was no water of crystallization present. Oxide of 
copper was employed at first for the combustions, but they were 
subsequently undertaken with chromate of lead, on account of the 
large proportion of carbon that excretine contains; no substance 
having been found to combine with it, its atomic composition was 
calculated from the assumption that one equivalent contained one 
equivalent of sulphur; and the following formula was obtained:— 
78 eq. Carbon .......... 468 
78 eq. Hydrogen .:...... 78 
Leg. SulphieeSait sj eee 16 . 
Dey Oxysewt cee 140s VIG 
Atomic weight of Excretine 578 
In my former communication I had stated that when the tissue of 
the spleen is submitted to a process of analysis similar to that adopted 
for the extraction of excretine, a substance closely allied to choleste- 
rine is obtained. This subject being one of great importance in a 
physiological point of view, I have resumed the investigation, and 
placed beyond doubt that this substance is really cholesterine. Its 
presence in the spleen is evidently independent of that which might 
exist in the blood retained by this organ after death. Is it that the 
spleen secretes cholesterine? This can only be determined by actual 
experiment; but it is very remarkable that a part of the blood 
which is supplied to the liver should come directly from an organ 
containing large quantities of a substance known to enter into the 
composition of the bile. 
“Description of a Chronometer Compass.” By Ralpb Reeder, 
Esq., of Cincinnati, U.S. 
This instrument is a combination of the Universal Dial and Chro- 
nometer, and is intended to show the errors of the magnetic needle, 
* In my former communication I had erroneously stated that excretine con- 
tained nitrogen, which resulted from my not haying been able to prepare a sufti- 
ciently large quantity of the substance; and, moreoyer, it might not haye been 
perfectly pure, 
