248 Kiihne and Chittenden— Peptones. 
Cleavage of the peptones. 
As already mentioned, Millon’s reaction appears very brilliant with 
amphopeptone, but more or less imperfectly with antipeptone. As 
the reaction is sure only under certain circumstances we have not 
neglected to perform it in every possible way, either by using the 
same concentration of solutions of the two peptones under exactly 
the same conditions, or by trying the most successful variations of the 
experiment for antipeptone. Thus it was found that the preparations 
C, D, E,and F, treated in a suitable way, gave an appreciable reaction, 
but in no case so that more than a dirty, generally orange red pre- 
cipitate was obtained. On the contrary, all trials with gland pep- 
tone purified with phosphotungstic acid, failed to give more than a 
simple yellow color. Since Millon’s reaction for albumin corresponds 
with the so-called Hoffmann’s test for tyrosin, and since with albu- 
min it probably depends on the separation of tyrosin by boiling 
with the acid solution of murcuric nitrate, if not by the formation of _ 
further decomposition products of tyrosin (hydroparacumarice acids) 
which likewise redden with the test, it might be presumed that anti- 
peptone, in contrast to the amphopeptone of pepsin digestion, forms 
no tyrosin by cleavage. So far as the action of trypsin is concerned, 
this was already known, since the real difference between gastric and 
pancreatic peptones consists in the fact that only the former, when 
treated with trypsin, yield tyrosin together with leucin and other 
decomposition products—in our opinion because they contain hemi- 
peptone capable of further cleavage (together with antipeptone). 
It was also known to us, however, that antipeptone during cleavage 
with boiling sulphuric acid yields the amido acids, and among them 
also tyrosin. Renewed investigations on this subject appeared called 
for now, since we thought ourselves in possession of much purer pre- 
parations of antipeptone. 
First, we established the possibility of decomposing with trypsin, 
amphopeptone entirely free from albumose. A few hours’ digestion 
in a small test tube, of 1 gram of peptone in 10 ¢. ¢. of water, contain- 
ing 0°25 per cent. of sodium carbonate with a little thymol and a 
fragment of purified pepsin, sufficed for this purpose. By concen- 
trating the neutralized solution and boiling the residue with alcohol, 
a decided residue was obtained in which balls of leucin and bundles 
of tyrosin were to be seen under the microscope without further 
preparation. The residue was also colored a beautiful violet with 
bromine water. We also sacrificed a large quantity of ampho- 
peptone to the same experiment and obtained the tyrosin pure (free 
a 
