226 ELEMENTAEY PHYSIOLOGY. [XXI. 



b. Add drop by drop HCl 1 p.c, the hsemo- 

 globin will be split up and the proteid 

 constituent precipitated ; add an equal bulk 

 of ether and shake, the colouring matter 

 (hsematin) will be largely dissolved in the 

 acid-ether ; with a pipette remove the lower 

 stratum of fluid, add a few drops more acid 

 and place at about 40° C, the proteid precipi- 

 tate will be converted into acid-albumin and 

 dissolved ; neutralize, it will be precipitated 

 and may be examined for the ordinary cha- 

 racters of acid-albumin. 



11. Place a drop of blood on a glass slide, and by 

 gently warming evaporate it to dryness : add to 

 it a grain of salt, and thoroughly mix it with the 

 blood, rubbing the whole to a fine powder. 

 Cover with a cover-slip, and let a little glacial 

 acetic acid run under it. Warm the slide, not 

 too rapidly, over a flame till bubbles appear 

 under the cover-slip; then let it cool, and ex- 

 amine under a microscope with a high power. 

 A large number of crystals of haemin as 

 brown-red rhombic prisms will be seen. 



DEMONSTRATIONS. 



The spectra of 



a. Hsematin in acid and alkaline solutions. 

 i. Hsematin reduced in an alkaline solution. 

 The gases of the blood. 



