400 Dr. Waller on the Origin of Mucus and Pus-globules. 



generally the diameter was only much decreased without being 

 entirely disconnected, so as to interrupt the course of the 

 blood. I have sometimes seen vessels of considerable size 

 with an internal rapid current, the tubes of which at some 

 places were contracted to one-fifth of the size which they 

 presented elsewhere. It is easy to explain this, if we suppose 

 that on some occasion they had been perforated by corpuscles 

 and narrowed as I have described. 



The corpuscles do not escape merely from vessels desti- 

 tute of internal current. Capillaries with a most rapid current 

 are often seen to be uneven, with slight indentations along 

 their sides, and at a short distance external corpuscles which 

 are more numerous opposite the indentations. In these cases, 

 the various analogies visible with regard to the indentations 

 and the corpuscles situated directly opposite to them outside 

 the vessel, show that the vessel must have given them pas- 

 sage in the same manner as when the blood is stagnant or in 

 a state of feeble oscillation. The larger trunks never present 

 any distinct indentations to mark the passage of the corpuscle 

 through them; but at their exterior corpuscles are fre- 

 quently seen collected in abundance, which renders it pro- 

 bable that the parietes of these also may be dissolved to allow 

 of the passage of these particles, which, however, must not be 

 confounded with that condition which I have termed extra 

 fibrination. A careful observer will easily distinguish the glo- 

 bular particles of what is probably condensed or coagulated 

 fibrine, from the corpuscles, as they are much more minute 

 and have no granular structure. 



The results of other experiments performed in the same 

 way are so similar to the above, that it would be a needless 

 repetition to detail them. When an animated being is the 

 subject, there must necessarily be some slight variation in the 

 results. Thus in some of my observations I find a difference 

 in the period which elapses before the injection and engorge- 

 ment takes place, and the succeeding phenomena are likewise 

 affected in proportion. I will briefly mention another obser- 

 vation, as it was attended with a loss of blood, and may serve 

 in some respects to elucidate the influence of depletion on ca- 

 pillary circulation. 



Obs. 2. — While the tongue of the frog was being secured, one 

 of the trunks of the lingual vessel was ruptured near the jaw- 

 bone and the blood escaped in abundance : from its dark co- 

 lour and the continuous manner in which it flowed, a vein pro- 

 bably had been torn. The depletion thus produced represented 

 on a small scale the operation of bleeding, to which we have 

 such frequent recourse in medicine. To the naked eye the dis- 



