BY DR. LAUDER BRUNTON. 433 



** 17. Preparation of a Solution of Acid Albumin 

 or Syntonin. Put some solution qf albumin in water into 

 a beaker and mix it with its own bulk of dilute hydrochloric 

 acid (four cubic centimetres of strong commercial acid in one 

 litre of water). Pour some of the mixture into several test- 

 tubes. The dilute acid does not convert the albumin immedi- 

 ttfrh/ into syntonin. Add to the fluid in the first test-tube a 

 drop of litmus solution, and then neutralize it exactly with 

 dilute liquor potass;-,-. Little or no precipitate will fall. If 

 any should be produced, filter, and boil the filtrate or add tan- 

 nin to it. A copious precipitate will appear, showing that 

 there is much albumin in the solution. The prolonged action 

 f the acid converts it into synlonin, which is precipitated by 

 neutralization. Let one tube stand for some hours, and then 

 examine it, or prepare it some hours before, and examine it 

 at the same time as the rest. Put a drop of litmus into it, 

 divide the liquid into two parts and then neutralize one part 

 exactly. The whole of the albumin will be precipitated Trom 

 the liquid. To show this, filter and boil the filtrate; no precipi- 

 tate will be produced. Acid albumin is not precipitated from 

 acid solutions by boiling. Boil the other part of the liquid. 

 The albumin in it has been already sh< Reconverted into 



syntonin. No coagulation will occur. jrmation of acid 

 albumin is accelerated by heat. Warm a test-tube containing 

 albumin solution mixed with acid gently to boiling. Add a 

 drop of litmus solution, and neutralize. The albumin will be 

 completely precipitated, and the solution, when filtered, will 

 give no precipitate on boiling. 



t ^ijntoniu is precipitated from its solutions by neutraliza^T 

 tion.rn'D though alkaline phosphates be pre&nt. Repeat the*** 

 last experiment, adding a little sodium phosphate before 

 neutralizing. The syntonin will be precipitated as before. 



* 18. Behavior of Syntonin with Acids. Syntonin 

 is soluble in concentrated mineral acids; it is insoluble in 

 them when they are moderately dilute, and it is soluble in them 

 when very dilute. 



Heat a watery solution of albumin gently to boiling, with 

 its own bulk of very dilute Hydrochloric or nitric acid (four 

 parts of commercial acid in 1000 of water). No coagulum 

 will be produced. Add a small quantity of strong acid and a 

 precipitate will form which will dissolve in a large quantity of 

 the acid, especially when heated. 



Put a little serum albumin into three test-tubes, and add to 

 one concentrated nitric acid, to another hydrochloric, and to- a 

 third sulphuric acid. Dissolve the albumin in the acid by 

 heating. 



Dilute the solutions with twice their volume of water, and a 

 precipitate will fall. Let it settle, and pour off the siiperua- 

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