THE BLOODVESSELS IN INFLAMMATION. 149 
puscles to become more closely aggregated than in the normal 
liquor sanguinis. This greater agglomeration of the red cor- 
puscles Mr. Jones attributes to the greater viscidity of the 
plasma thus produced. 
Section 2 . — Phenomena of the Flow of the Blood in the 
Vessels of the Web. 
(a) In the Vessels generally . — The red corpuscles move 
rapidly along the middle of the stream ; the colourless corpuscles 
roll sluggishly along, or actually stagnate next the walls of the 
vessels. The latter phenomena are said, b;y Mr. Jones, to be 
due to a strong tendency on the part of the colourless corpuscles 
to adhere to the walls. The force of the stream is in general 
sufficient to counteract this tendency ; but when the flow of 
blood is retarded, then accumulation of large numbers of colour- 
less corpuscles takes place. 
The tendency of the red corpuscles to adhere to each other 
(they having no tendency in the natural state to adhere to the 
walls of the vessels) is overcome by the normal force with which 
the blood is propelled. If any impediment occurs to the free 
passage of the blood, then the red corpuscles “ become applied 
to each other by their flat surfaces.” There is no tendency to 
adhesion between the red and colourless corpuscles, either with- 
in or without the body. 
(b) In the Arteries . — At each pulsation the artery is seen 
under the microscope to become slightly dilated. The pulsa- 
tions of an artery are observed to be less and less evident, down 
to the capillaries. When an artery has been cut across, pulsa- 
tion continues above but ceases below the wound. 
In cases in which arteries were seen dilated at one spot while 
elsewhere they were of usual width, Mr. Jones states that re- 
tardation of the stream of blood in passing into the wide channel 
was, in his observations, well marked, the stream becoming again 
accelerated on entering the narrow channel. 
Speaking of the flow of blood through arteries in a state of 
general dilatation, our author affirms, that it — i. e., the flow of 
blood — is more rapid in them than in arteries of the usual 
width ; “ the resistance to its motion from friction being 
diminished in the dilated vessels.” 
(c) In the Capillaries , the flow of blood is continuous, and, 
in general, slow enough to allow of the individual corpuscles 
being distinctly seen. “ When any impediment,” to use Mr. 
Jones’s own words, “ to the flow of blood from the capillaries 
into the veins occurs, the red corpuscles may be seen to ac- 
cumulate, and to become applied to each other by their flat 
surfaces, with their diameters more or less nearly at right angles 
to the axis of the vessel.” 
