244 Kiihne and Chittenden— Peptones. 
and mercuric iodide in potassium iodide, while imperfect precipitants 
of peptones are phosphotungstic acid or phosphomolybdic acid and 
picric acid. 
The following list shows the further action of various reagents. 
Reactions of Peptones free from albumose and purified by phos- 
photungstic acid. 
In 5 per cent. solution, after being made noticeably alkaline with 
a trace of sodium carbonate. 
Fibrin antipeptone. 
Fibrin amphopeptone. 
Acetic acid and potassium|At first perfectly clear, later trace/The same. 
ferrocyanide. 
of opalescence. 
Neutral lead acetate. 
First drop, 0; more, turbidity. 
The same, but much 
weaker. 
Basic lead acetate. 
Turbidity | immediately “more, 
strong turbidity. 
The same, but weaker. 
Mercurie chloride. 
First drop, 0; more, strong tur- 
bidity. 
Turbidity immediately, 
growing stronger. 
5 per cent. cupric sulphate. | At first clear ; more, slight turbid- Nothing. 
ity disappearing with great ex- 
cess. | 
5 per cent. platinum chloride./Only excess, strong turbidity. IN othing. 
Chromic acid. Nothing. Nothing. 
Ferric chloride. A trace gives turbidity vanishing) Nothing. 
with the least excess. 
Glacial acetic acid and conc.|Brownish red. |The same. 
sulphuric acid. 
Nitric acid. The color changing yellow in the The same. 
cold. 
Boiling with cone. hydro- The color becomes slightly darker./The same. 
chloric acid. 
Millon’s reaction. 
At first a heavy white precipitate ; 
on warming, dirty yellow or 
reddish. 
The same, then beauti- 
ful red color. 
Without desiring to claim especial value in general for these reac- 
tions and for smaller differences between the two peptones, some of 
them, however, may be more closely examined. 
The slight intensification of color by boiling with concentrated 
hydrochloric acid is striking, for we have not ordinarily been able to 
obtain it, even with peptone in substance or even on the addition of 
