On the theory of inflammation / [John James Drysdale].

  • Drysdale, J. J. (John James), 1817-1892.
Date:
1838
Catalogue details

Licence: Public Domain Mark

Credit: On the theory of inflammation / [John James Drysdale]. Source: Wellcome Collection.

    15/80 (page 7)
    to me, be explained on mechanical principles. It is not yet agreed whether the capillaries contribute to the circulation of the blood, though it is probable that they do not; but it is certain that the motion of the blood must be considerably retarded in its passage through them by friction at least, if not also by the vital processes which take place in them. Therefore, according to Dr Young (Phil. Trans. 1809), 44 The more the capillary arteries are debilitated and distended, the greater will be the mean velocity of the circulation ; but whether or no the velocity will be increased in the vessels which are thus distended, must depend on the ex¬ tent of the affected part; and it may frequently happen, that the velocity may be much more di¬ minished on account of the dilatation of the space which the blood is to occupy, than increased by the diminution of the resistance.55 (P. 26.) From this it appears, that a relaxation of the capillaries would, by diminishing resistance, tend to increase the velocity of the blood’s motion, till the dilatation proceeded so far, that the increased quantity of blood to be moved more than compen¬ sated for the diminution of resistance. It is there¬ fore possible, for a mechanical reason, that dilata¬ tion when it is slight and equable, may be accom¬ panied with increased velocity of circulation ; but whether the increased velocity in question is to be