Kithne and Chittenden—Peptones. 239 
phuric acid, the solution concentrated, the peptone precipitated and 
washed with alcohol and finally boiled with alcohol. The partially 
dry product was then dissolved in cold water, leaving a small amor- 
phous residue which gave no reaction for tyrosin. The solution 
was then concentrated on the water-bath and again precipitated 
with alcohol, after which it was dried finally, over sulphuric acid in 
vacuo and at 106° C. in vacuo, until of constant weight. 
The following table shows the results of the analysis. 
Antipeptone (H). (Gland peptone.) 
This product was prepared and purified in exactly the same manner 
as the former one (G), but was made from another trypsin prepara- 
tion, in which a smaller amount of dry pancreas was used. When 
dissolved for the last time in cold water, some little insoluble matter 
remained (from which it was freed) which, however gave no reaction 
for tyrosin. : 
The following table shows the results of the analysis. 
GENERAL PROPERTIES OF THE PEPTONES. 
We should have liked to study more accurately the physical be- 
havior of the different samples of peptones, especially their optical 
properties as determined by specific rotary power. It was easy to 
show that they were all laevo-rotary, but we have not yet succeeded 
in making any quantitative determinations of sufficient accuracy to 
be of value. The decidedly brown color of the solutions prevented 
the use of a sufficiently long tube, or a solution of the proper concen- 
tration, necessary to determine specific rotation. 
It would be of still greater importance to investigate the rate of 
diffusion of peptones, it being more necessary from the fact, that pre- 
vious observations on the diffusion of the products of digestion can 
have but little reference to pure peptones, but rather to the albumose 
bodies so long overlooked. We have, however, not as yet begun these 
investigations owing to lack of material. All of the peptones obtained 
by us in the dry state, showed considerable rise of temperature when 
moistened with, or dissolved in water. 
It is worthy of notice, physiologically, that according to observations 
made in the physiological Institute at Heidelberg, by Dr. Pollitzer 
of New York, no one of the peptones would hasten or retard coagu- 
lation of the blood, either when injected into the veins or added to the 
shed blood, such action being due wholly to certain of the albumose 
bodies. 
