APPENDIX. 191 



the stomach, for example, when the animal is bled, as is often done, 

 by cutting off its head) gets mixed with it. Put this bottle aside 

 until the blood clots, and carry it home with the least possible 

 shaking. Next day the mass will exhibit a beautiful clot floating in 

 serum. The latter will probably be tinted red, as the jolting in 

 conveying the specimen from the slaughter-house shakes some of the 

 corpuscles out of the clot into the serum. 



7. In the other bottle collect blood and beat it vigorously with the 

 twigs for three or four minutes. Next day this specimen will not 

 have clotted, but on the twigs will be found a quantity of stringy 

 elastic material (fibrin), which becomes pure white when thoroughly 

 washed with water. 



8. Take some of the serum from specimen 6. Point out that it 

 does not coagulate spontaneously. Heat it in a test tube over a spirit 

 lamp; the albumen will be coagulated and the whole will become 

 solid. 



9. Place a small quantity of whipped blood (7) on a piece of 

 platinum foil. Heat over a spirit lamp. After the drop dries it 

 blackens, showing that it contains much organic matter. As the 

 heating is continued this is burnt away, and a white ash, consisting 

 of the mineral constituents of the blood, is left. 



