INFLAMMATIONS 5 



of Dr. Browne Langrish on this subject, afford no conclusion, 

 having been made on certain parts of the blood, separated from 

 the rest, without attending to the circumstances of blood-letting, 

 which very much alter the state of separation and concretion of 

 the blood drawn out of the veins. 



3. The supposition of a preternatural lentor or viscidity of 

 the blood is not well founded ; for it is probable, that nature 

 has specially provided against a state of the fluids, so incompa- 

 tible with the exercise of the most important functions of the 

 animal economy. While motion continues to prevent any se- 

 paration of parts, and heat continues to preserve the fluidity of 

 the more viscid, there seems to be always so large a proportion 

 of water present, as to give a sufficient fluidity to the whole. 

 I must own, that this is not absolutely conclusive ; but I still 

 repeat it, as giving a probability to the general argument. 



4. In the particular case of inflammation, there are several 

 circumstances which render it probable, that the blood is then 

 more fluid than usual. 



5. I presume that no such general lentor, as Boerhaave and 

 his disciples have supposed, does ever take place ; because, if 

 it did, it must shew more considerable effects than commonly 

 appear. 



6. Besides the supposition of an obstructing lentor, physicians 

 have supposed, that an obstruction may be formed by an im- 

 permeable matter of another kind, and that such an obstruction 

 may also be the cause of inflammation. This supposition is 

 what is well known in the schools under the title of an error 

 loci; but it is an opinion that I cannot find to be at all proba- 

 ble : for the motion of the blood in the extreme vessels is so 

 weak and slow as readily to admit a retrograde course of it ; 

 and, therefore, if a particle of blood should happen to enter a 

 vessel whose branches will not allow of its passage, it will be 

 moved backwards, till it meet with a vessel fit for transmitting 

 it ; and the frequent ramifications and anastomoses of the ex- 

 treme arteries are very favourable to this. I must own, indeed, 

 that this argument is not absolutely conclusive ; because I al- 

 low it to be pretty certain, that an error loci does actually upon 

 occasion happen : but, for the reasons I have given, it is pro- 

 bable that it seldom happens, and is therefore rarely the cause 



