528 Trans. Acad. Sci. of St. Louis. 
The filtrate from 2 is boiled so as to throw out any egg 
albumin that might not have been coagulated by the first heat- 
ing on account of the presence of the acid. 
For the cupro-proteic reaction, Wenz * recommends the use 
of a 15 p. c. sodium hydroxide solution, and a 0.2-0.5 p. ¢. 
cupric sulphate solution added drop by drop. I prefer not 
to name the rose-red cupro-proteic reaction a ‘** Biuret ’’ re- 
action for the reason that a lamentable confusion exists with 
regard to this term: some physiologists apply it to the violet 
and rose-red cupro-proteic reactions, others limiting it to the 
latter. Biuret is a nitrogenous decomposition product obtained 
on heating urea to 120°. It responds to many reactions char- 
acteristic to proteid bodies, hence Pickering | recommends 
the use of the term ‘‘ Biuret ’’ in a generic sense. He offers 
at the same time new terms for the two cupro-proteic re- 
actions: for the violet —‘* iono-proteic’’ (7o»—a violet), and 
‘*rhodo-proteic ’’ for the rose-red reaction (‘s4d07——a rose). 
The popularization of this proposed change should be 
hailed with gratification by all who have truly scientific ter- 
minology at heart. In quoting Pickering I take pleasure in 
mentioning his recommendation of the sulphate of cobalt as a 
delicate reagent for detection of proteid bodies. The colors 
struck by it with the different proteid bodies are so charac- 
teristic as to preclude any possible error of discernment, 
while that much cannot be said of the violet and rose-red of 
the cupro-proteic reaction. 
For the separation of the albumoses of which Ewald in his 
scheme mentions but one, the propeptone of Schmidt-Muehl- 
heim, or Kuehne’s protalbumose, I modified Ewald’s procedure 
by substituting saturation with ammonium sulphate for the sat- 
uration wan sodie peas on addition of acetic acid. Wenz? 
has sati trated that ammonium sulphate, under 
certain conditions; will throw down all proteids except the true 
peptones. Ewald follows the method recommended by Boas, 
the results of which Chittenden § has proved to be without 
* Wenz, Zeitschrift f. Biologie, Vol. XXII 
t Pickering, “‘ Proteid Reactions,” Journal of Physiology, Vol. XIV., 1893. 
t Wenz, Zeitschrift f. Bioiogie, Vol. XXII. 
§ Chittenden & Hartwell, “Proteoses & Peptones,” Journal of Physi 
ology, Vol. XII, 1891. 
