178 OF THE BLOOD. 



upon the fibrin. 1 The effect of complete abstinence from food, also, or of a con- 

 tinued insufficient supply of it, is to reduce the proportion of the whole solid 

 constituents ; but in this case, too, the corpuscles are much more reduced than 

 the albumen ; and very little effect is produced upon the fibrin, which at once 

 undergoes an absolute increase, if any inflammatory affection should develop 

 itself. 



162. The effect of Loss of blood is of a very similar nature to that of absti- 

 nence. Almost as soon as the stream begins to flow from a wounded vessel, 

 there seems to be a transudation of watery fluid from the tissues into the current 

 of blood j for this undergoes a rapid diminution in ' density, so that the portion 

 last drawn is of lower specific gravity, and contains a considerably smaller 

 amount of solid matter, than that which first issued. This fact, which has long 

 been known, has of late been more precisely determined by Drs. Zimmerman, 3 

 Polli, 3 and J. Davy. 4 When blood has been repeatedly drawn, or has been lost 

 by hemorrhage, that which remains is impoverished ; but the reduction in its 

 whole amount of solid matter here too lies rather in the diminution of the cor- 

 puscles, than in that of the other constituents. This is shown by the following 

 table of the results of MM. Becquerel and Rodier's analyses of the blood of 

 ten patients, each of whom had been bled three times : 



1st Venesection. 2d Venesection. 3d Venesection. 



Specific gravity of defibrinated blood 1056.0 1053.0 1049.6 



serum 1028.8 1026.3 1025.6 



Water . 



Solid Residue 



Fibrin . 



Corpuscles . 



Albumen 



Extractive and saline matters 



Fat 



793.0 807.7 833.1 



207.0 192.3 176.9 



3.5 3.8 3.4 

 129.2 116.3 99.2 



65.0 63.7 64.6 



7.7 6.9 8.0 



1.6 1.6 1.5 



Hence it is obvious that the special effect of bleeding is to lower the proportion 

 of red corpuscles, and that it has no power of effecting a diminution in the 

 amount of fibrin. We shall find, indeed, that in inflammatory diseases the 

 amount of fibrin undergoes an extraordinary increase ( 176), which is not 

 checked in the slightest appreciable degree by the most copious venesection. 



163. 'We have now to consider the differences which present themselves in the 

 composition of the blood drawn from different vessels of the same body; these, 

 it is obvious, being dependent on the changes to which the fluid is subjected, 

 during its passage through organs that will appropriate or change its several 

 constituents in an unequal degree. And the first and most important of these 

 sets of differences is that which exists between Arterial and Venous blood. 

 The analyses already cited having been made chiefly upon the latter, it will be 

 sufficient here to state the general results of comparative inquiries into the com- 

 position of the former. The quantity of solid constituents pertaining to the 

 Corpuscles is smaller ; they contain relatively more hsematin and salts, but much 

 less fat. The liquor sanguinis is somewhat richer in Fibrin; but it contains a 

 larger proportion of water, and consequently less Albumen. The Fatty mat- 

 ters of the serum, as well as of the corpuscles, are considerably diminished ; on 

 the other hand, the Extractive matters are decidedly increased. It is affirmed 

 by Dr. G-. 0. Rees, 5 that the phosphorus which exists in venous blood in an 



1 See on this subject the treatise of M. Emile Marchand, "De 1'Influence comparative 

 du Regime Vegetal et du Regime Animal sur le Physique et le Moral de 1'Homme." 



2 "Heller's Archiv," band iv. p. 385. 



3 See " Medico-Chirurgical Review," Oct. 1847. 



4 "Anatomical and Physiological Researches," vol. ii. p. 28. 

 6 "Philosophical Magazine," vol. xxxiii. p. 28. 



