III.] COAGULATION OF BLOOD, 45 



4. Place a small drop of fresh blood on a piece of 

 glazed neutral litmus paper, in about ten seconds 

 wipe off the drop, a blue spot will be left showing 

 that the blood is alkaline. Test also the reaction 

 of serum. 



5. Apply the Xanthoproteic and Millon's test for 

 proteids (op. § 16) to fibrin chopped up and 

 suspended in water. 



6. Take two test-tubes and in each place a few 

 flocks of fibrin. 



a. Add water and place in water bath at about 

 39° G. for a day ; the fibrin does not dissolve 

 (it thus differs from albumin and peptone). 



h. Treat similarly but with dilute (1 p. c.) solu- 

 tion of sodic chloride; the fibrin does not 

 dissolve (it thus differs from globulin). 



7: Place two or three flocks of fibrin in a test-tube 

 containing a few c. c. of "2 p. c. HCl, the fibrin 

 soon swells up and becomes transparent; neu- 

 tralize the acid with Na^COg, the fibrin shrinks 

 to its original size. If the fibrin is warmed with 

 the acid, solution slowly takes place, acid-albu- 

 min being formed (cp. Lesson ix.). 



8. Examine the plasma of horse's blood kept, by 

 means of cold, from coagulating ', 



1 The blood is allowed to run from the animal into a taU narrow 

 vessel contained in a much larger one packed with ioe, a little salt 

 may be mixed with the ice, but of course not enough to reduce the 

 temperature so much that the blood is frozen; sometimes also a vessel 



