182 



If in these expörimeiits much fibi'in is taken in proportion to 

 alkali or acid-solution then it will be observed that the lluid is 

 entirely imbibed bj' the fibrils. Eveiy fibre is seen to swell strongly, 

 has become jelly-like, and more or less transparent. (We mean here 

 the ordinary, raw fibrin ; [)ure fibrin gives less striking results because 

 it is dissolved very quickly by alkali and acid, so that the swelling- 

 stage is only very short). 



The separate coarser fibrils are at first still plainly visible in the 

 swollen mass q,s jelly-like strings. 



If a coarse fibril, swollen by dil. alkali, e.g. NaOH 0.2 7o' is 

 placed in dil. acid so that the fluid becomes about neutral, then 

 the swollen fibril gradually resumes its original form and qualities; 

 it becomes elastic again as before. If the fibril is not placed in 

 diluted, but in concentrated acid, the swollen fibril resumes its shape 

 and qualities much sooner. This is also the case if the swollen fibril 

 is put into solution of acid phosphate of sodium or a solution of 

 acid phosphate of calcium. Hence we have to deal here with a 

 reversible process. But not only by acids and acid salts the fibre, 

 swollen by alkali, may be brought again into its original state, it 

 may also be effected by a 1 "/^ CaClj-sol. or by a saturated sol. of 

 NaCl or NaFl, or by any other saturated salt-solution, such as 

 MgSO^ or (NHJ, SO^. And it also appeared that a fibril, swollen 

 by alkali, also gradually resumes its original form and qualities, if 

 it is placed in an excess of water, and moie (piickly by shaking it 

 with much water. It is a remarkable fact that the swollen fibril 

 retains these qualities also when the swollen Jihril is boiled first, at 

 least if the alkali is in a weak concentration and has not acted too- 

 long. Also after being boiled the fibril, swollen by 0.207o NaOH, 

 returns to its original state as regards shape and qualities, when 

 exposed to acid, salt, or an excess of water. 



It follows that the process which takes place wdien fibrin is swol- 

 len by diluted alkali, must be of a very superficial kind, and that 

 ordinary chemical process, or change is out of the question. 



Between fibrin on the one hand and alkali on the other, only an 

 extremely loose compound, an adsorption-coinpound can have been 

 formed. 



The logical conclusion is that all component parts of the swollen 

 coarse fibril, first the smaller fibres, next the smallest fibres, and 

 lastly the minutest parts of which these smallest fibres consist, have 

 formed an adsorption-compound with the alkali, and are consequently 

 swollen. 



But it must also be inferred that the component parts and parti- 



