III.] COAGULATION OF BLOOD. 47 



The mixture will clot very speedily if placed 

 in the warm chamber ; less speedily if left at 

 the ordinary temperature. 



[>. Remove about lOc.c. into a small conical glass. 

 Add powdered sodic chloride to excess, stirring 

 but not more than is necessary to assist the 

 salt to dissolve. As the point of saturation 

 is reached, a flaky precipitate makes its 

 appearance. If the precipitate be plentiful, 

 remove it with a spatula, put it on a small 

 filter wetted with a saturated solution of 

 sodium chloride and wash with small quan- 

 tities of the same: if the precipitate be 

 small, decant it and the fluid from the 

 undissolved salt ; filter, and wash the pre- 

 cipitate on the filter paper with small quan- 

 tities of a saturated sodic chloride solution. 

 Dissolve the substance so obtained, the plas- 

 znine of Denis, in a small quantity of dis- 

 tilled water, and filter. Probably a portion 

 of it will not dissolve, having already coagu- 

 lated. The clear, colourless fluid filtrate will, 

 if set on one side, clot. Avoid shaking after 

 filtration. If a small quantity only of the 

 fibrin factors be present, the fine threads of 

 fibrin, as they are formed, are loosened by 

 the shaking, and contract; thus the more 

 easily recognized gelatinous stage is lost. 

 This operation is the more successful, the more 

 rapidly it is carried on. 



10. To 2 c.c. of hydrocele or other serous fluid which 



