360 PROTEIN-COMPOUNDS. 



have been fully discussed, and when we enter on the theory of the 

 animal juices, that we can form a sound judgment on such subjects. 

 Origin. Taking into consideration everything connected with 

 the occurrence of fibrin, we can scarcely entertain a doubt that it 

 is formed from albumen, and not directly from the protein-con- 

 taining food ; for its occurrence in the chyle is not opposed to this 

 view, partly because, as Henle has shown, fibrin may be conveyed 

 to this fluid by the lymphatics and blood-vessels, and partly be- 

 cause, as I have fully convinced myself, all the juices of the animal 

 body not only contain free carbonic acid but also free oxygen. It 

 was formerly supposed that the formation of fibrin from albumen 

 might very easily be accounted for ; since, according to the older 

 analyses of Mulder, fibrin contained one half less sulphur than the 

 albumen of serum, nothing seemed more simple than to assume 

 that the oxygen conveyed by the respiration to the blood, converted 

 half of the sulphur of the albumen into sulphuric acid, and that 

 this combined with its alkali, so that fibrin was now evolved. These 

 and all similar views have become untenable since more recent analyses 

 of albumen and fibrin have been made. If we would at present 

 start an hypothesis regarding the formation of fibrin, it can only 

 rest on the slight excess of oxygen which fibrin contains over albu- 

 men. The indication afforded by this fact has led, however, to 

 serious error in reference to the increase of the fibrin in inflam- 

 mations : since it was concluded that, although we may not know 

 how the oxygen finds its way to the albumen to form fibrin, it is at 

 all events incontestable that the latter is formed by a process of oxi- 

 dation or eremacausis; and it was further very erroneously concluded 

 that the augmentation of the fibrin in inflammation is dependent 

 on an increased rapidity of the process of oxidation, and that con- 

 sequently inflammation is nothing more than an actual process of 

 combustion. This hypothesis originally propounded by chemists, 

 was for a long period accepted by physicians, without any doubts 

 occurring as to its correctness. In accordance with chemical prin- 

 ciples, an excessive supply and absorption of oxygen might indeed 

 be regarded as the cause of an increase of fibrin ; but even this is 

 by no means proved ; for how would it then be possible that in 

 pneumonia, where a greater or lesser part of the lungs is hepatised, 

 that is to say, is rendered impermeable to air, a greater quantity of 

 fibrin should be found in the blood than during other inflammatory 

 affections ? This has lately been referred to the greater frequency 

 of the respirations, but independently of the circumstance, that in 

 inflammation of other parts, the number of the fibrin should then 



