ACTION OF REAGENTS. 131 



Miscellaneous reagents. 



8. Absolute alcohol. Take 5 CC of the solution, add an equal 



volume of alcohol, the proteid partly falls out of solution, 

 not however completely. 



9. Coagulation by Ether. Upon 2 cm in a tube pour an equal 



quantity of ether, a cloud forms at the junction. The 

 fluid must be neutral. 



10. Tannin. To 5 CC add an equal volume of a 10 p - c - solution 



of tannic acid ; a white pp occurs. 



Precipitation by neutral salts. MgSO 4 , (NH 4 ) 2 S0 4 written 

 Am 2 SO 4 . 



11. Precipitation of globulins. Half saturate 5 CC of No. 2 by 



adding an equal volume of saturated solution of Ain 2 SO 4 . 

 Make the latter by dissolving in 5 CC of hot water as 

 much of the salt as will dissolve, and whilst warm (40 C) 

 add it to the warmed proteid solution. The white pp 

 will not be a pronounced one owing to the small quantity 

 of globulin present. Complete saturation with MgSO 4 

 has the same result. 



12. Precipitation of albumin. Saturate completely with Arn 2 SO 4 , 



To ensure saturation warm the fluid to about 40 C. 

 and add the salt until some of it remains undissolved 

 at the bottom of the tube. As water takes up about 

 1 volume of the salt not more than 8 CC of the solution 

 should be employed, in order that the process of satura- 

 tion may not be too protracted. The cloud will be best 

 seen above the undissolved salt. 



