THE BLOOD. 09 



If the solutions of fibrinogen and paraglobulin be mixed, the mixture 

 cannot be distinguished from a solution of plasmine, and like that solu- 

 tion (in a great majority of cases) firmly clots; whereas a mixture of the 

 hydrocele fluid and serum, from which they have been respectively taken, 

 no longer does so. In addition to this evidence of the compound nature 

 of plasmine, it may be further shown that, if sufficient care be taken, 

 both fibrinogen and paraglobulin may be obtained from plasma: fibrin- 

 ogen, as a flaky precipitate, by adding carefully 1 3 per cent, of crystalline 

 sodium chloride; and after the removal of fibrinogen from the plasma by 

 filtration, paraglobulin may be afterward precipitated, on the further 

 addition of the same salt or of magnesium sulphate to the filtrate. It is 

 evident, therefore, that both these substances must be thrown down to- 

 gether when plasma is saturated with sodium chloride or magnesium sul- 

 phate, and that the mixture of the two corresponds with plasmine. 



Presence of a Fibrin Ferment. So far it has been shown that 

 plasmine, the antecedent of fibrin in blood, to the possession of which 

 blood owes its power of coagulating, is not a simple body, but is composed 

 of at least two factors viz., fibrinogen and paraglobulin; there is reason 

 for believing that yet another body is associated with them in plasmine 

 to produce coagulation; this is what is known under the name of fibrin 

 ferment (Schmidt). It was at one time thought that the reason why 

 hydrocele fluid coagulated when serum was added to it was that the latter 

 fluid supplied the paraglobulin which the former lacked; this, however, 

 is not the case, as hydrocele does not lack this body, and if paraglobulin, 

 obtained from serum by the carbonic acid method, be added to it, it will 

 not coagulate, neither will a mixture of solutions of fibrinogen and para- 

 globulin obtained in the same way. But if paraglobulin, obtained by 

 the saturation method, be added to hydrocele fluid, it will clot, as will 

 also, as we have seen above, a mixed solution of fibrinogen and para- 

 globulin, when obtained by the saturation method. From this it is evident 

 that in plasmine there is something more than the two bodies above men- 

 tioned, and,that this something is precipitated with the paraglobulin by 

 the saturation method, and is not precipitated by the carbonic acid 

 method. The following experiments show that it is of the nature of a 

 ferment. If defibrinated blood or serum be kept in a stoppered bottle 

 with its own bulk of alcohol for some weeks, all the proteid matter is pre- 

 cipitated in a coagulated form; if the precipitate be then removed by 

 filtration, dried over sulphuric acid, finely powdered, and then suspended 

 in water, a watery extract may be obtained by further filtration, contain- 

 ing extremely little, if any, proteid matter. Yet a little of this watery 

 extract will determine coagulation in fluids, e.g., hydrocele fluid or 

 diluted plasma, which are not spontaneously coagulable, or which coagu- 

 late slowly and with difficulty. It will also cause a mixture of fibrinogen 

 and paraglobulin, obtained by the carbonic acid method, to clot. This 



