177 



an addition of an equal volume of water, containing CO^, to a fibrin- 

 NaOH-solntion, brought about turbidity and a subsetnient eoaguluni 

 of libres. As a rule I saw already after some minutes that flakes 

 were formed round the beads of CO^, which had adhered to the 

 side of the test-tube. These flakes formed the starting-point for further 

 thread-formations. The beads of CO^, being weak acid-centres with 

 a great surface, became the starting-i)oint of the coagulation, a 

 mechanical factor playing undoubtedly a certain part since on the 

 precipitate or coagulum, formed at the surface of a CO^-bead, other 

 precipitated colloid particles could settle. 



Besides with fibrin-solutions in diluted NaOH, experiments were 

 also carried out with solutions of pure fibrin in strongly diluted 

 NajCOg-solutions. Fibrin was found to dissolve very well in diluted 

 NajCOa-solutions, whilst on the other hand it was insoluble, or 

 almost so, in solutions of NaHCOg. 



The results, obtained with solutions of fibrin in diluted Na^CO.,, 

 were entirely analogous to those obtained with fibrin-NaOH-solu- 

 tions, as appears from the following example, which may also serve 

 to prove that a CaCO^-sohition could effect coagulation in fibrin- 

 NajCOj-solutions, which was indeed also the case, though it was 

 not nientioned before, in fibrin-NaOH-solutions. 



Pure fibrin was put in a 0.2 7o Na^COg solution in which it 

 dissolved rather easily. 



To 10 cc. of this fluid were added : 



1. 10 cc water containing CO^. 



2. 10 cc water containing CO^ -{- 1 cc of a 0.47o CaCl2-solution. 



3. 10 cc of a 0.47„ CaCl^ solution. 

 The result was as follows : 



The coagula obtained in 1,2, and 3 were then put into a 0.1 7o 



12 



Proceedi tit's P>(ival Aofirl. Ampterd.mn. Vol. XVI. 



