181 



Like serum, watery organic extraots, for instance a watery extract 

 of calf's thjmus-gland, were found to effect coagulation in fibrin 

 NaOH-solutions and in ascites- fluid. 



Ad 3. Thirdly fibrin-NaOH-solutions would have to act upon 

 saturated NaCl- and NaFl-solutions in the same way as fibrinogen- 

 solutions, such as plasm which is kept fluid or transudates. 



By the addition of an equal volume of saturated NaCi-sol. to 

 fibrin-NaOH-solution, flakes and jelly-like strings were obtained, 

 just as when an equal volume of saturated NaCl-solution was added 

 to plasm which was kept fluid or to ascites-fluid. A saturated 

 NaFl-solution immediately effected coagulation as a rule, and that 

 in all 3 fluids. The agreement in both respects between fibrin-NaOH- 

 solutions on the one hand, and plasm which is kept fluid and 

 ascites-fluid, on the other, was, therefore, a striking one. 



The result of these series of experiments removed all doubts as 

 to the accuracy of the foregoing provisional conclusions. / felt 

 absolutely certain Jioiu that fibrin can be brought from a gel-state 

 into a sol-state and vice versa. And moreover that the sol-state, caused 

 by the solution of fibHn in strongly diluted alkali and not the one 

 obtained by the solution of fibrin in diluted acid, must be considered 

 identical loith ''fibrinogen" as found in blood and body- fluids. 



.How are we to conceive the transition of flbrin from the gel-state 

 into the sol-state under the action of diluted alkali or acid, and 

 also the return from the sol-state to the gel-state under the influence 

 of this action ? 



The following experiments and considerations may supply an 

 answer to this question. The ordinary impure flbrin, as formed 

 when blood is beaten up and likewise pure flbrin, formed at 

 spontaneous coagulation of plasm which is kept fluid, contains a 

 certain amount of water, is swollen to a certain extent. By drying 

 the washed-out fibrin, for instance by exposing it to the air, this 

 water evaporates. The dried fibrin is brittle, hard and not elastic. 

 If, however, the dried fibrin is placed in water, it swells again, whilst 

 its elasticity returns. 



Also if a dried fibril was boiled in water it began to swell, and 

 became elastic as at first. This swelling caused by water is, however, 

 a very restricted one. But if the ordinary, moist fibrin or the air- 

 dry fibrin are exposed to water, to which alkali or acid have been 

 added, the fibrin swells much more than by water only; undoubtedly 

 we have to deal here with a swelling-process, introduced bj water. 



