362 PROTEIN-COMPOUNDS. 



mentation, the intermediate stages which during the process of acid 

 fermentation present themselves between the two extremes of spirit 

 of wine and acetic acid. We know that by a gradual process of 

 oxidation, aldehyde and aldehydic acid are formed from the spirit, 

 although these two substances may not become apparent : the beau- 

 tiful investigation of Mulder regarding the Mycoderma aceti affords an 

 almost more analogous illustration; its cellulose can onlybeproduced 

 by a process of oxidation from the alcohol ; moreover, in the forma- 

 tion of this cellulose from the alcohol there must first be formed an 

 aldehyde-like substance poorer in oxygen than cellulose ; hence al- 

 dehyde may just as well be produced during the oxidation of alcohol 

 into acetic acid, as during its oxidation into cellulose. In a per- 

 fectly analogous manner we may regard the fibrin as representing 

 one of the stages in the oxidation of the albumen, w r hich is transferred 

 either into the tissues or into the secreted substances. There seems 

 to us to be no discrepancy between the above observations on the che- 

 mical importance of fibrin, if we will only leave nature unfettered with 

 divisions into progressive and regressive metamorphoses. For, if we 

 assume the formation of tissue to be the highest stage of animal 

 metamorphosis, fibrin pertains to the ascending or progressive 

 series, inasmuch as it yields the proximate stratum for the develop- 

 ment of cells and the formation of tissues ; on the other hand, it 

 must be classed in the descending or regressive series, in so far as 

 its quantity in the blood is found to be increased in diseases, or 

 after the excessive use of albuminous food, when it does not be- 

 come converted into tissue but is changed by oxidation into the 

 ordinary excreted matters. For we cannot believe that, as in the 

 percussion-apparatus of Physicists, a given quantity of fibrin will 

 repel and displace a corresponding amount of tissue. In short, we 

 seem to be nearest the truth in regarding fibrin as representing one 

 of the most common stages in the metamorphosis of albuminous 

 substances. 



We must not conclude our observations on fibrin without 

 noticing a very common error that has crept into pharmacology from 

 the misunderstanding of a chemical fact. Many physicians believe 

 that the antiphlogistic power of nitrate of potash is explained by 

 the chemical fact that spontaneously coagulated fibrin dissolves in 

 a solution of nitre. Without entering into the question whether this 

 salt actually possesses the power ascribed to it, we assert that this 

 mode of explanation is altogether untenable, for it is difficult to 

 draw the conclusion that nitre can prevent the formation or aug- 

 mentation of fibrin in inflammatory blood, simply because coagu- 



