20 



ESSENTIALS OF CHEMICAL PHYSIOLOGY 



LESSON III 

 THE PB0TEID8 (continued) 



1. Action of Acids and Alkalis on Albumin. — Take three test-tubes and 

 label them A, B, and C. 



In each place an equal amount of diluted egg-white, similar to that used 

 in the last lesson. 



To A add a few drops of 0'1-per-cent. solution of caustic potash. 



To B add the same amount of O'l-per-cent. solution of caustic potash. 



To C add a rather larger amount of 0"l-per-cent. sulphuric acid. 



Put all three into the warm bath ^ at about the temperature of the bodv 

 (36-40° C). 



After five minutes remove test-tube A, and boil. The proteid is no 



l''l(j. 6.— Simple warm bath, as described in footnote. 



longer coagulated by heat, having been converted into alkali-albumin. After 

 cooling, colour with litmus solution and neutralise with 0"l-per-cent. acid. 

 At the neutral point a precipitate is formed which is soluble in excess of 

 either acid or alkali. 



Next remove B. This also now contains alkali-albumin. Add to it a few 



' A convenient form of warm bath suitable for class purposes may be made by 

 placing an ordinary tin pot half full of water over a bent piece of iron which 

 acts as a warm stage as in the figure. The stage is kept warm by a small gas 

 fiame. Such a warm bath may be placed between every two or three students. 



