General Principles of Physiology. 107 



vessels of the different parts of the body deriving their power 

 from the corresponding parts of the spinal marrow. That the 

 vessels possess a power capable of supporting the motion of the 

 blood, independently of the heart, appears from direct ex- 

 periment *, and this power seems to obey the same laws with 

 that of the heart. Both the brain and spinal marrow may 

 be removed, or slowly destroyed, without impairing itf, yet 

 it is immediately enfeebled or destroyed by suddenly crushing 

 either of these organs J. It also appears from experiments 

 related in the Inquiry just referred to, that the excitability 

 of the alimentary canal is equally powerful after as before the 

 removal or slow destruction of the brain and spinal m arrow §. 

 The same, we know, is also true of the muscles of voluntary 



* Exper. Inq. Ex. 24. 62. 63. I wish particularly to impress on the reader, 

 that it appears from the experiments here referred to, that both in warm 

 and cold-blooded animals the capillary Tessels are capable of performing 

 their part in the circulation, after the removal of the heart, provided a 

 ligature had been previously thrown round all the vessels attached to it, 

 and seem to perform it as perfectly as in the healthy animal ; for we can- 

 not observe, in such experiments, that the velocity of the blood in these 

 vessels is immediately lessened, or in any other way changed, by the 

 removal of the heart ; a proof that the circulation in the capillaries depends 

 little, if at all, on the power of that organ. If medical writers would keep 

 tliese results in view, it would prevent many of the observations daily made 

 on the nature of inflammation, on whicb,Jas far as 1 am capable of judging, 

 more fallacious reasouing, and a greater disregard of well-established facts, 

 have been displayed than on any other subject of equal importance in our 

 profession. They began with Mr. Hunter's classing a morbid, with a na- 

 tural process, and have taken a thousand shapes since his time. But their 

 authors should recollect that, unless they can disprove the positions, as- 

 certained by the simplest, and consequently least equivocal, experiments, 

 that any cause lessening the action of the capillary vessels causes, and 

 any cause exciting these vessels relieves inflammation, what tliey say 

 can be of no weight. If their arguments cannot otherwise be answered, 

 which I believe would be no difficult task, an appeal to the simple matter 

 of fact is always at hand, 



t. Exp Inq. Exper. 12, 13, t I^- Exper. 28, 29. 



§ Exper. Iwj. Exper. 46, 47. Mr. Andrew Knight observed to mc, 

 that he has frequently seen the peristaltic motion of the intestines of the 

 rabbit strong alter tbcy were t:ikcu out of the body. 



