162 LABOR A TOR Y G UIDE IN PHYS1OLOG Y. 



d. To prepare acid albumin, To 100 c.c. of dilute egg 

 albumin add an equal quantity of 0.2% hydrochlo- 

 ric acid; place the mixture in the incubator for two 

 or three hours. Though the change begins at once it 

 will probably not be complete before the time suggested. 

 If one wishes to isolate the acid albumin from the mix- 

 ture he has only to carefully neutralize with sodic hy- 

 droxide precipitating the acid albumin, and to wash the 

 precipitate with distilled water. For the purposes for 

 which it is to be used in the following demonstration it 

 may be left in the acid solution which represents 0.1% 

 HC1. 



Label: Acid Albumin Solution in 0.1% HC1. 

 e . Make an aqueous solution of the commercial "pep- 

 tone," and though peptone is present in small propor- 

 tion, label it: Proteoses. 



f. Make an aqueous solution of a few grammes of Grii- 

 bler's pure peptone, and label: Peptone. 



g. Dissolve a few grammes of gelatin in distilled water. 

 h. To prepare Millorfs reagent: 1st. To 100 grammes of 



pure mercury add an equal weight of concentrated 

 nitric acid c. p. The reaction proceeds at room 

 temperature, though gentle heat may be applied to 

 complete the solution of the mercury. 2d. Cool the 

 mixture; add two volumes of water; after 12 hours 

 decant the supernatant liquid Millon's Reagent. 

 3. Experiments and Observations. 



(1) Pour into test tubes a few cubic centimeters of 

 each of the following proteid solutions and subject 

 each in turn to a temperature of 57C, then to a tem- 

 perature of 63C, and finally a temperature of 100C, 

 by dipping the tubes into waterbaths of the tempera- 

 tures named: 



(a) Dilute egg albumin. 



