DR. MARCET ON THE IMMEDIATE PRINCIPLES OF HUMAN EXCREMENTS. 4H 
result. Excretine burnt with carbonate of potash and nitrate of potash, yielded no 
phosphorus. 
The quantitative analysis was first attempted by combustions with oxide of copper, 
but it was soon found out that from the large proportion of carbon present, it was neces- 
sary to employ a more powerful oxidizing compound, and consequently the formula was 
obtained from combustions with chromate of lead. The proportion of sulphur was 
determined in the usual way, by burning the substance with carbonate of baryta and 
nitrate of potash. 
I. 0T45 gramme of crystallized excretine yielded,— 
Sulphate of Baryta . . . . 0*0 32, 
corresponding to Sulphur . . 0-004; or in 100 parts of excretine . 2*758 
II, 0-107 gramme of crystallized excretine yielded, — 
Sulphate of Baryta .... 0*027, 
corresponding to Sulphur . . 0*003; or in 100 parts of excretine . 2*803 
Average per-centage 2*780 
The combustions mth oxide of copper yielded, — 
I. For 0*071 gramme of excretine. 
Carbonic acid . 
0*211 
'*■' — --5 
Carbon . 
. 0*057 
Carbon . 
For 100 parts. 
. 80*281 
Water . , . 
0*087 
Hydrogen . 
, 0*009 
Hydrogen 
. 12*676 
II. For 0*1115 gramme of excretine. 
Carbonic acid , 0*318 Carbon . . 
0*0898 
Carbon . 
For 100 parts. 
. 79*81 
Water . . . 
0*121 
Hydrogen . 
0*0134 
Hydrogen 
. 12*01 
In these analyses* the carbon was not far from correct, as the gaseous products 
(sulphurous and sulphuric acid) formed at the expense of the sulphur of excretine had 
made up for the loss depending on the incomplete combustion of the substance ; that 
the excretine was not perfectly burnt is shown by the amount of hydrogen obtained, 
which is too low. 
The combustions with chromate of lead yielded, — 
I. For 0*1458 gramme of crystallized excretine. 
Carbonic acid . 0*430 Carbon . . 0*117 
Water . . . 0*182 Hydrogen , 0*020 
II. For 0*1355 gramme of crj'stallized excretine. 
Carbonic acid . 0*400 Carbon . . 0*109 
Water . , . 0*167 Hydrogen . 0*018 
For 100 parts. 
Carbon . , 80*412 
Hydrogen . 13*746 
For 100 parts. 
Carbon . . 80*442 
Hydrogen . 13*284 
* In the analysis with oxide of copper the tube containing peroxide of lead had not been used. 
3 H 2 
