50 PROPERTIES OF 



lated : there was however this difference in the two cases, that 

 in mine the fluid was red, so that it formed a red crust over 

 the first, which was white. Now this seems to have been owing 

 to the blood's having first coagulated, where it was in contact 

 with the air and with the sides of the cup ; and the fluid which 

 gushed out was the serum, with a part of the coagulable lymph, 

 which still remained fluid; but, when exposed to the air, it 

 jellied or coagulated, as it naturally does. That one part of 

 the lymph can remain fluid after the other is coagulated, is 

 proved by some of the preceding experiments ; and I have more 

 than once seen blood which appeared perfectly jellied soon 

 after bleeding ; yet, on cutting into the coagulum, a transparent 

 fluid has oozed out, which afterwards jellied. And so slowly 

 does this coagulation proceed in some cases, that, in an experi- 

 ment mentioned before, a part of the blood in a dog's heart 

 was found uncoagulated thirteen hours after death. And 

 I have likewise distinctly observed, that in some cases 

 where the disposition to coagulate was much lessened during 

 the evacuation, the blood at the bottom of the cup has jellied, 

 whilst the greatest part of the size at the top was yet fluid; 

 there being only a thin pellicle on its surface, where it was in 

 contact with the air (xxvi) . 



Another instance of a change in the properties of this coagu- 

 lable lymph, which appears curious, was seen in some experi- 

 ments, where I had occasion to throw the blood into water, and 

 into oil, during the winter season, whilst the heat of the water 

 and of the oil was no greater than 41 of Fahrenheit's scale. 

 In all those experiments, I found that the disposition to coagu- 

 late was lessened, the blood becoming more and more viscid, 

 but did not coagulate whilst in that degree of cold. I shall 

 next relate those experiments. 



EXPERIMENT XXII. 



The jugular vein being properly tied, and then cut out from 

 a rabbit just killed, was then thrown into water of 41 of heat, 



(XXVT.) See Exp. xvi, and Notes xii, x, xm and in, i. k. I have 

 repeatedly removed a clot as soon as it was formed, and observed that 

 it was succeeded by another. Dr. Davy a noticed the same fact. 



a Researches, Physiol. and Anat. ii, 68. 



