74 PROPERTIES OF 



disposed to concrete (XLVI). But it is not a certain sign of 

 inflammation, and does not appear to be the cause of that dis- 

 ease, but only its effect. 



But the most remarkable conclusion that these experiments 

 have led to is, that the properties of the blood depend on the 

 state of the blood-vessels, or that they have a plastic power over 

 it, so as to be able to change its properties in a very short 

 time (XLVII). The novelty of this opinion, and the difficulty 

 of conceiving how the vessels should have so remarkable a 

 power, has made some object to the conclusion, who had not 

 well considered all the facts from which it was deduced. I 

 shall here therefore sum up these facts. 



That the blood-vessels, by their stronger or weaker action, 

 can change the properties of the lymph, even in the short time 

 spent in filling the different cups in bleeding, is first inferred 

 from Experiment 19th, where the blood in the first cup had a 

 size, whilst that in the others had none. Now as this want of 

 size in the last cups was owing to the lymph having by this 

 time become thicker, and to its being more disposed to coagu- 

 late, and no other circumstance being observed that could 

 account for this alteration (for the difference in the expo- 

 sition to cold or to air even then appeared inadequate to the 

 effect, and are now proved to be so by Experiment xxxi), I 

 concluded, that it was entirely owing to an alteration in the 



1132. Dr. Benj. Babington a estimated the specific gravity of fibrin at 

 1079, by putting it into a saline solution. But this estimate is proba- 

 bly too high ; for a strong solution of salt may increase the specific 

 weight of the fibrin, by depriving it of some of its natural moisture. 

 Thus I have ascertained that a slice of the buffy coat of the horse's 

 blood will float at first and afterwards sink in a solution of nitre, sp. 

 gr. 1 132 ; in a solution of Glauber's salt, sp. gr. 1084 ; and in a solution 

 of muriate of soda, sp. gr. 1 176. After the fibrin had been some weeks 

 in these solutions their specific gravity became diminished, that of the 

 nitre, for instance, being 1108, no doubt in consequence of the 

 moisture extracted from the fibrin. In every instance they were 

 weighed at a temperature of 60. The fibrin did not appear to be at 

 all dissolved. The objection of Dr. Babington to calculating the weight 

 of the corpuscles by immerging them in saline solutions, entirely agrees 

 with my own experience : (see Notes xxm and xxix). 



(XLV.) See Notes xxm and xxix. 



(XLVI.) See Note xxi. 



(XLVII.) See Note xxiv. 



a Cyclopaedia of Anat. and Physiol. i, 418. 



