32 PROPERTIES OF 



still fluid. I likewise observed that the coagulation first began 

 on the surface, where it was in contact with the air, and formed 

 a thin pellicle ; this I removed, and saw that it* was soon suc- 

 ceeded by a second. I then took up a part of the clear liquor 

 with a wet teaspoon, and put it into a phial with an equal 

 quantity of water ; a second portion I kept in the teaspoon ; 

 and I found afterwards that they both jellied or coagulated, as 

 did also the surface of the crassamentum, making a thick crust. 

 On pressing with my finger that portion which was in the tea- 

 spoon, I found it contained a little serum. 



From this experiment it is evident, that the substance which 

 formed the size was fluid after it was taken from the vein, and 

 coagulated when exposed to the air ; and as this is a property 

 of the coagulable lymph alone, and not of the serum, there 

 can be no doubt that the size was formed of the lymph (xix). 



The following experiment, made on the blood, without expos- 

 ing it to the air, likewise proves the same fact. 



EXPERIMENT XII. 



Immediately after killing a dog, I tied up his jugular veins 

 near the sternum, and hung his head over the edge of the 

 table, so that the parts of the veins where the ligatures were 

 might be higher than his head. I looked at the veins from 

 time to time, and observed that they became transparent at 

 their upper part, the red particles subsiding. I then made a 

 ligature upon one vein, so as to divide the transparent from 

 the red portion of the blood ; and opening the vein, I let out 

 the transparent portion, which was still fluid, but coagulated 

 soon after. On pressing this coagulum, I found it contain a 



ously alone, nor after dilution merely with distilled water. The blood- 

 corpuscles, as mentioned in Note cxviu, cannot be the immediate agents 

 in the formation of fibrin in these mixtures of serum. Dr. Buchanan 1 

 has since found that the liquid of hydrocele will coagulate when there 

 is added to it either some washed blood-clot, shreds of the fresh bufty 

 coat, the same dried and powdered, the transparent clot from a blister, 

 or muscular fibre and other tissues. He and Dr. Anderson are now 

 satisfied that the fibrin exists in the animal fluids in a state of solution, 

 (xix.) I know not that this simple and convincing experiment was ever 

 before made. The claiming of it by Professor Owen for Mr. Hunter 

 has been noticed in the Introduction. 



1 Lond. Med. Gaz. 1845, vol. i, pp. 617 et seq. 



