286 CIRCULATING FLUIDS: 



is only changed by the cells of the organs^ throngh which it passes, 

 possessing the inherent power of abstracting and appropriating 

 from it tlie substances requisite for their nourishment. It is 

 different, however, with the active metamorphosis of the blood, 

 in which the corpuscles are changed at the expense of the 

 plasma. If the general circulation be hastened, the blood will 

 be urged more frequently through the lungs and other organs 

 that exert a modifying influence on its composition. 



Hence the blood (passing more frequently through the 

 lungs) gives off a larger amount of carbon in the form of car- 

 bonic acid than in the normal condition. If, as I have endea- 

 voured to show (pp. 155 and 219), the blood-corpuscles take 

 an essential part in the respiratory process, and their vital 

 activity, evolution, and revolution are only carried on vnih the 

 cooperative agency of the atmospheric origin, then, in propor- 

 tion to this increased cooperation, will their development be 

 hastened, their vitality heightened, and more corpuscles be con- 

 sumed than in the normal state. 



Two important conclusions may be drawn from my theory, 

 regarding the production of fibrin from the blood-corpuscles, 

 viz. that the amount of fibrin is increased, and of blood-cor- 

 puscles diminished. This is the more striking, since the in- 

 crease of fibrin during the development of the corpuscles does 

 not keep pace with its consumption in the act of peripheral 

 nutrition, and since the supply of blood-corpuscles afforded by 

 the chyle cannot be proportionate with the diminution produced 

 by the accelerated circulation.^ 



Hence, if we only assume that the circulation is increased 

 by the reaction of the organism in inflammatory aftections, an 

 explanation is at once afforded us of the change that occurs in 

 the composition of the blood in hyperinosis, and at the same 

 time of its heightened temperature. We do not, however, mean 

 to imply that the increased circulation is the sole cause of the 

 change in the blood, for it can hardly be denied that the nerves 

 exert an influence on its constitution ; moreover, as we have 

 already shown, venesection modifies its characters. 



' It has been suggested that l)lood in which there is an excess of fibrin increases 

 the energy of the heart's action, while blood deficient in fibrin diminishes it. The 

 rapid circnlation of the blood in inflammations and its torpid condition in certain 

 typhoid affections seems in favour of this view. 



