228 FUNCTIONS OF NUTRITION. 



of the original plasma. This substance is the so-called "plasmine;" 

 and if redissolved by the addition of water, its solution coagulates, 

 yielding 3 parts of a solid matter, like fibrine, and 22 parts of a liquid 

 substance, having the properties of paraglobuline. The albumen of the 

 plasma (53 parts per thousand) remains in the sodium sulphate solu- 

 tion, not having been precipitated by the addition of sodium chloride. 



This theory is defective, because the material termed "plasmine," 

 may be, from the first, a mixture of two different substances, one coag- 

 ulable and the other not so, but both precipitable from the sodium 

 sulphate solution by sodium chloride. In that case, it would not facili- 

 tate the explanation of the process. In point of fact we know that both 

 the fibrine-producing substance and paraglobuline may be thrown down 

 from their solutions by the addition of sodium chloride in excess. 



According to the theory of Schmidt, the coagulable fibrine is pro- 

 duced by the union of two previously existing substances, neither being 

 coagulable by itself. One of these substances is fibrinogen, present in 

 the blood in small quantity ; the other is paraglobuline, present in large 

 quantity. When the fibrinogen, therefore, has all been converted into 

 coagulated fibrine, there still remains in the serum a surplus of para- 

 globuline, which may cause coagulation in other liquids, provided they 

 contain fibrinogen. The liquid usually employed to demonstrate this 

 property is that of hydrocele, which does not coagulate spontaneously, 

 but may sometimes be made to do so by the addition of blood-serum. 



It was found, however, that both fibrinogen and paraglobuline might 

 be present in a liquid, and yet fail to produce coagulation. The author* 

 of the theory therefore recognized the existence of a third substance, 

 the "fibrine ferment," which was essential to induce the combination 

 of the other two. According to this view, fibrinogen and paraglobuline 

 both exist in the blood while circulating in the vessels ; and, when they 

 unite, supply the material for the coagulated fibrine. But the ferment 

 which excites their combination only appears in the blood during or 

 after its withdrawal. It may then be extracted by the process already 

 described (p. 81). 



There is no doubt in regard to the existence and character of the 

 fibrine-ferment. Its mode of operation is analogous to that of other 

 organic ferments. In the first place it acts in very small quantity in 

 proportion to the amount of coagulation produced. Secondly, its action 

 is confined within certain limits of temperature, being retarded by cold, 

 and permanently arrested by the heat of boiling water. Thirdly, 

 though precipitable by alcohol, it is not destroyed by this substance, 

 but after precipitation may be redissolved in water, with its properties 

 unchanged. Fourthly, after inducing coagulation, it still remains in 

 the fluid separated by filtration, and may be again repeatedly used for 

 the same purpose, with only a very slow diminution of its activity. 

 This shows that it does not contribute by its substance to the coagu- 



* Archiv fur die gesammte Physiologic. Bonn, 1872, Band vi., p. 413. 



