4-18 ON IRRITANTS AND COUNTER-IRRITANTS. 



of its albuminous constituents increased. The two brothers 

 Ernest Heinrich and Edward Weber ascribed it, without more 

 <ido, to coagulation of the blood in tlie capillaries ; and it seems 

 to mc that the view taken by those two wonderful men, althougli 

 long forgotten, is after all the right one.* It does not conflict 

 with that of Cohnheim, for the coagulation, if such be present, 

 no doubt owes its occurrence to changes in the vessels. 

 Briicket has found that, while blood remains fluid in living and 

 healthy vessels, it coagulates in them when they die, so that we 

 would naturally expect any injury which lessened their vitality 

 would tend to cause coagulation within them ; and Wharton 

 Jones has actually noticed coagula form in the vessels after 

 pressure upon them. The absence of any fibrinous threads in 

 the interior of the vessels of inflamed parts does not in the 

 least disprove coagulation ; for, when experimenting with tho 

 plasma from horses' blood, I have seen tlie contents of a glass 

 tube, from 1 to 2^ inches in diameter, in wliich th^re were three 

 layers, the upper one of pure liquor sanguinis, the middle oi 

 liquor sanguinis phis white blood-corpuscles, and the third of 

 red corpuscles with liquor sanguinis, all apparently fluid. It 

 was only when I attempted to turn them out that I found 

 coagulation had occurred. Even when turned out, the soft 

 clots showed no sign of structure, until they had been squeezed 

 in the hand, and then fibrinous threads became perceptible. If 

 coac^ulation thus failed to become visible in such a lar!][e tube, 

 the absence of any easily recognised sign of it in a small capil- 

 lary is not astonishing. The chief difficulty in the way ot 

 accepting Weber's theory is tlie occurrence of stasis, when 

 defibrinated blood or milk is made to circulate through the 

 vessels. But defibrinated blood, when made to circulate in this 

 way, takes up something while in the vessels, which re-imparts 

 to it the power to coagulate, so that it may form a clot after it 

 has issued from the veins. So far as I know, no similar experi- 

 ments have been made with milk, but it is possible that it too 

 acquires so much coagulating power as to cause stasis. In the 

 absence of the requisite data, it is impossible to look upon 



* VircTiotv's Archiv, 1857, p. 152. 



f Briicke, Virchow's Archiv, 1857, p. 1G3. 



