Emigration i?i Passive Hypercemia. 41 



tissue corpuscles, causing the familiar thickening of the skin 

 and vascular walls. In support of this view is the fact that 

 the increase in thickness in the wall of a varicose vein is due to 

 hyperplasia, not of the muscular elements, but of the connect- 

 ive tissue bundles interposed among those elements, and of the 

 outer coat of the vessel which is composed wholly of connective 

 tissue. So, too, the enlargement of the spleen which usually fol- 

 lows portal obstruction, as in cirrhosis of the liver, and the thick- 

 ening of the superior hemorrhoidal veins — " hemorrhoids " — 

 from the same and other conditions, are to be referred, in part 

 at least, to the development of leucocytes which have wandered 

 from the vessels during the mechanical congestion. Perhaps, 

 too, the areolar hyperplasia so often found with displacements 

 of the uterus is due to the venous congestion which usually 

 exists in that condition. 



Even the conservatives like Strieker and Rindfleisch, while 

 insisting on proliferation of pre-existing cells as the more im- 

 portant source of connective-tissue hyperplasia, admit the 

 strong probability that a considerable part of it is due to the 

 development of the wandering cells or colorless corpuscles first 

 into spindle cells, then into fibrillated tissue. Certain it is 

 that, in the repair of wounds, at least, they play a prominent 

 part in the formation of cicatricial tissue. 



The fact of emigration without any evidence of that " nutritive 

 irritation" of tissue, which Virchow presumes in active hyper- 

 aemia, would seem to favor Hering's view that the exit of cor- 

 puscles is a passive rather than an active movement, due to 

 their glutinosity, to increased blood pressure and diminished 

 blood velocity — in short, a simple filtration of colloid sub- 

 stances. 



Then again the behavior of the small red corpuscles is inter- 

 esting as exhibiting their close relation with the white, and as 

 furnishing another link in the chain of circumstantial evidence 

 that the red corpuscles are transformed white ones. Such has 

 for some time been the prevalent opinion, though never com- 

 pletely demonstrated. The fact that these red ones were but 

 little if any larger than the white, that they were of circular 

 shape, were devoid of nuclei, and possessed the power of 

 amoeboid motion, proves their close connection with the color- 

 less cells; while the presence of haemoglobin, as indicated by 

 their color, testifies to their ability to perform at least one im- 



