1885.] Blood and its Physiological Import. 71 



It is necessary for these experiments that the peptonisation should 

 be complete. 



For the complete understanding of these results, I must return- to a 

 further consideration of this new constituent of the plasma. 



The turbidity which appears on first cooling the plasma, if 

 examined microscopically, is found to consist of a great number of 

 minute pale transparent bodies of a rounded shape, much resembling 

 small organised bodies, such for instance as the stroma of the red 

 corpuscles, except that they are of very various size, but generally 

 much smaller than red corpuscles. They have a great tendency to run 

 together into granular masses. 



At first the precipitate is soluble on re-warming the plasma slightly, 

 but it soon undergoes change, and loses the power of redissolving by 

 heat. If the substance be collected by means of the centrifuge it 

 forms a disk or thin membrane at the bottom of the tube, much 

 reminding one of fibrin, but closer examination shows that it presents 

 marked differences from the latter, and that, in truth, it much more 

 closely resembles the peculiar viscid body obtained by destroying 

 leucocytes with dilute alkalies, &c. 



On longer standing, however, it becomes in most cases still 

 further changed, and is then undistinguishable from ordinary fibrin, 

 swelling in dilute HC1 like the latter. For further details as to the 

 properties of this substance, I refer to my paper quoted above. 



We have already seen that this substance gives rise to fibrin fer- 

 ment, but it does more than this in inducing coagulation. 



Fepton plasma is not coagulable with fibrin ferment. If we take 

 some plasma rich in this new substance, and by means of C0 2 induce 

 coagulation, we obtain, on removing the clot, a serum which has the 

 power of inducing exceedingly rapid coagulation in a new portion of 

 plasma, and this, when the serum has regained its alkalinity. This 

 serum contains ferment, but inasmuch as ferment is not sufficient 

 to induce coagulation, it must also contain some other substance. 

 Now leucocytes have exactly the same power. They give rise to 

 ferment, but they also give rise to the other substance necessary for 

 coagulation. 



We see, therefore, that we have dissolved in the plasma a body 

 exerting the same influence on the induction of coagulation as the 

 leucocytes. 



I think this is the strongest chemical proof that can be brought 

 that the leucocytes break down to make, at any rate, a part of the 

 proteid constituents of the plasma, and have shown above the influ- 

 ence which diet, &c, has on the extent of this process, a fact of 

 obvious interest for the question of assimilation. 



There is, however, another important conclusion to be drawn from 

 these observations, viz., that one must admit, in addition to the 



