NaOH-süliition in which 1 dissolved quickly, 2 slowly, and 3 very 

 slowly. It seemed as if CaCla, or Ca changed the coagulating sub- 

 stance in such a manner that it was difficult to dissolve it in strongly 

 diluted NaOH. With regard to CaCl.^ it appeared, therefore, that a 

 fibrin-NaÓH-solution (and also a fibrin-Na^COa-solution) had the same 

 properties as are known of fibrinogen-solutions. 



From the foregoing experiments it follows therefore : 



That, like impure librin, also pure fibrin, free from blood-cor- 

 puscles, could be dissolved by strongly diluted NaOH or Na4C03, 

 and by diluted acids. That the tibrin-solutions in alkali contained a 

 substance which, under the action of acids (also of COJ and likewise 

 of CaCij sol., could be obtained as a fibrous coagulum, whilst solutions 

 of strougly diluted acids could bo made to coagulate by diluted alkali. 



Whilst, however, the impure fibrin could be dissolved by dil. 

 alkali or acid, only after several days, the pure fibrin was discovered 

 to pass into solution in a much shorter time, often after only a 

 few minutes. 



Without entering into the question if it loould appear afterwards 

 ivhether a coagulating substance might be obtained from attendant 

 substances of impure Jibrin more particularly from its blood-cor- 

 puscles or their component parts, these ej'periments justifed the con- 

 clusion that at any rate pure fibrin, the coagulated substratum of 

 fibrinogen, inhen dissolved in diluted acid or alkali, supplied a sub- 

 stance ivhicli could again be made to coagulate. 



Meanwhile, I had grown more and more convinced in the course 

 of these experiments, that 1 had not got to deal with a new coagul- 

 able substance, formed from fibrin wdien it was dissolved, but with 

 fibrin itself in sol- and gel-state. 



And as the coagulation of fibrin is generally attributed somehow 

 to the action of a ferment (fibrin-ferment), it stands to reason that 

 repeatedly the question suggested itself if the coagulation in the fibrin- 

 solution, under the action of acids or alkali or CaCl^, would have 

 to be attributed to an action of these substances only, or if it might 

 also be due to a ferment-action. 



It was found that the latter, not unimportant question had to be 

 answered in the negative, at least if it may be assumed that such a 

 ferment would be destroyed by being boiled. 



For coagulation could be effected in fibrin-alkali- and also in 

 fibrin-acid solutions, even aftei' they had been boiled, under exactly 

 the same circumstances as in the case of the unboiled solutions. 



The results, hitherto obtained, gave i-ise to the following provisional 

 conclusions : 



