606 [June 11, 



that liquor sanguinis would always undergo the change when influenced 

 by ordinary matter. But an observation which I made not many 

 days ago, shows that this was a mistake. I obtained the jugular 

 vein of a horse, and having kept it for a while in a vertical position 

 till I could see through its transparent coats that the red cor- 

 puscles had fallen from the upper part, I removed all bloody tissue 

 from that part of the vein, and punctured it so as to let out the 

 liquor sanguinis into a glass. Finding after eighteen minutes 

 that the liquid had not begun to coagulate, I added a drop of 

 serum and corpuscles to a portion of it, and within seven minutes 

 there was a clot wherever the corpuscles lay, whereas the rest of the 

 fluid was still very imperfectly coagulated after another half hour 

 had elapsed. That the liquor sanguinis to which no addition had 

 been made coagulated at all, was sufficiently explained by micro- 

 scopic investigation, which showed not only abundant white cor- 

 puscles, but also several isolated red ones that had not subsided. This 

 observation was made three hours after the death of the horse, but I 

 obtained essentially similar results on repeating the experiment in 

 another horse an hour after death ; so that there can be no doubt 

 whatever that the fibrin was in the same condition as it is in the 

 blood-vessels of a living animal. The observation appears also par- 

 ticularly satisfactory on this account, that the liquor sanguinis was 

 not separated from the corpuscles by any process of transudation 

 through the walls of the blood-vessels, which might be conceived to 

 involve retention of some constituent of the liquid, which, though in 

 solution, might be unable to pass through their pores, but simply 

 by the subsidence of the corpuscles, which must have left all the 

 materials of the liquor sanguinis behind them. Hence it is proved 

 beyond question that if the liquor sanguinis could be separated 

 completely from the blood-corpuscles, it would resemble the fluid of 

 hydrocele in being incapable of coagulation when shed into a cup. 



Now this struck me as a very satisfactory and beautiful truth, in- 

 asmuch as it clears away all the old mystery of the distinction 

 between inflammatory exudations and dropsical effusions. Dropsical 

 effusions, exhibiting little disposition to coagulate, have been sup- 

 posed to consist almost exclusively of serum, and the exudqdjon of 

 the entire liquor sanguinis has been regarded as the special cha- 

 racteristic of inflammation; and very unsatisfactory theories have been 



