24 J.P. Norton on the Protein bodies of Peas and Almonds, 
undisturbed ina cool place during twelve to sixteen hours. 
Much difficulty was experienced in filtration. The coarser par- 
ticles were removed by a doubled linen cloth, and the greater 
portion of the finer by repeated filtrations through paper, doubling 
the filters toward the close. Even after four or five filtrations 
however, the liquids generally remained somewhat cloudy. The 
precipitates therefore, after being thrown down by acetic acid 
were collected, washed, and dissolved in dilute ammonia, by the 
aid of a gentle heat not above 60 to 70 degrees Celsius. ‘The 
solution almost always became colored ; if the ammonia employ- 
ed was strong, and the heat nearly at the boiling point, it turned 
almost black. The weaker the ammonia and the lower the heat, 
so much the lighter was its color. These solutions were after- 
ward filtered, and the substance again thrown down by acetic 
acid. ‘The coloring matter invariably went with the picepinete, 
leaving the filtered liquid almost entirely colorless 
The precipitate, thoroughly washed, was next boiled in alcohol 
and ether severally, until either ceased to extract anything ; 3 ity was 
then considered pure, 
at present extends, we have no more certain method of se 
In determination of the carbon and hydrogen, I have employ- 
ed the ordinary method, but for the nitrogen I have preferred the 
method of Dumas, substituting bicarbonate of soda, for carbonate 
of copper, and introducing one or two additional precautions, 
This method has given me most admirable results. I have tested 
it in various ways, and have compared it with a method of Prof. 
Mulder’s, in ie the substance is burned in an atmosphere of 
pure nitrogen, its accuracy has been most satisfactorily proved, 
but it is too complicated for general use. On burning the same 
substance by the two methods, I obtained in the one case 17:32 
per cent. and in the other 17-355. Dumas’s method is so simple, 
and with due precaution so accurate, that it has taken the place 
of all others in the Utrecht Laboratory since my series of Sapees 
ments upon it. 
For the determination of the sulphur I have tried a variety of 
methods. The first was that of burning with carbonate of potash 
and. nitre, in a platinum crucible over a lamp, the substance | ing 
first mingled with the two salts of potash in a mortar and thrown 
ato the crucible in small quantities as the carbon burned away. 
fhe melted mass is dissolved in dilute i: -aaaeetpiy sci and 
” sulphur thrown down as BaO,SO?. There is g danger 
f deflagration by this method, although with a pee good. 
moiiles: may be obtained. I also tried. mingling the substance 
with | a sen quantity of carbonate and a very small quantity of 
D , and burning in a glass tube to prevent loss. It 
a It, however, to control the combustion, and the caustic 
potash 1ed almost always attacked the glass, —_ a quan- 
tity of soluble silica. This last objection applies also, I think, 
3 & a SS 
