48 ELEMENTARY PHYSIOLOGY. [ill. 



has been ascertained not to coagulate, nor to have 

 coagulated spontaneously, add 2 c.c. of fresh blood- 

 serum, gently mix, and put on one side. 

 After a while, possibly not until after twenty- 

 four hours, the mixture will have coagulated. 

 The coagulation will be more rapid in the warm 

 chamber. 



11. Take 10 c.c. of fresh blood-serum and saturate it 

 with magnesic sulphate by adding the salt in 

 powder. Paraglobulin will be precipitated, 

 since like other globulins it is insoluble in a satu- 

 rated solution of a neutral salt; filter (before 

 filtering the precipitate may be allowed to settle 

 and most of the fluid removed by decantation), 

 wash on the filter with a saturated solution of the 

 salt, then add 5 c.c. water to the precipitate, the 

 salt solution clinging to the precipitate will be 

 diluted and the paraglobulin dissolved. It does 

 not coagulate spontaneously. 



12. Add a small quantity of paraglobulin solution to 

 hydrocele fluid. Coagulation will result. 



13. Treat 10 c.c. of hydrocele or pericardial fluid with 

 sodium chloride to saturation, and proceed as in 

 11; a precipitate of^fibrinogen will be ob- 

 tained, its solution does not coagulate sponta- 

 neously. 



14. Add to 1 c.c. of a strong solution of fibrinogen an 

 equal volume of blood-serum, and set aside ; 

 coagulation will take place. 



15. Take 2 c.c. of plasma ( 9), add to it 16 c.c. of 



