50 ELEMENTARY PHYSIOLOGY. [ill. 



dilute serum, add a few drops of nitric acid, 

 and boil. The white precipitate of proteid 

 material at first formed becomes yellow and 

 partially dissolves, forming a yellow solution. 

 If the quantity of proteids present is small, 

 the yellow solution only will be obtained. 

 Place the test-tube in a stream of water from 

 a tap to cool and when cold add ammonia; 

 the yellow is turned to orange. 



I). To another small quantity of the serum add 

 a few drops of Millon's re-egent 1 . A pre- 

 cipitate will be formed which tarns pinkish 

 on boiling; if the amount of the proteids 

 present be small, no distinct precipitate will 

 be formed but the fluid will turn pink on 

 boiling. 



c. Add a drop of cupric sulphate solution to an 

 excess of sodium hydrate. To the blue solu- 

 tion so formed add a little dilute serum, the 

 fluid will become violet (cp. reaction of pep- 

 tone, Lesson xvi.). The violet colour be- 

 comes deeper on warming. 



d. Add strong spirit, a precipitate is formed 

 (peptone in solution is precipitated with 

 difficulty). 



e. Add excess of acetic acid and a few drops of 

 a strong solution of potassium ferrocyanide, a 

 precipitate is formed (peptone is not thus 

 precipitated). 



17. With the diluted serum or white of egg observe 



1 Cp. Appendix. 



