44 ORGANISED FLUIDS. 



But there are other facts which will serve to explain the 

 difference of position : thus the red corpuscles have an attrac- 

 tion for each other, as is manifested on the field of the mi- 

 croscope by the formation of the strings of corpuscles already 

 referred to, where also it is seen that they have no such 

 affinity for the white corpuscles, which usually lie detached 

 and isolated from the red. On the other hand, however, the 

 white, as before stated, have an attraction for the walls of the 

 vessels through which they pass, and which is declared by 

 their frequent adhesion thereto. 



The question may be asked, have these attractions any thing 

 to do with electric conditions ? All the inquiries which have 

 been undertaken with the view of proving that the blood is 

 possessed of electric properties have hitherto signally failed 

 to demonstrate the existence of any. 



Lastly, what inference is to be deduced from the different 

 positions occupied by the two kinds of blood corpuscles, and 

 from the different rates of their circulation in the capil- 

 laries ? 



The rapid passage of the red corpuscles through the capil- 

 laries, together with their central situation, would lead the 

 observer to infer that they had but little direct relation with 

 the parts outside those capillaries, that the office discharged by 

 them was one of distribution, whereas the slow progress of the 

 white corpuscles through the capillary vessels, as well as their 

 peripheral position, would lead to the conclusion that a close 

 relation existed between them and the parts adjacent and 

 external to the vessels. Now these deductions are precisely 

 those which other facts and observations tend to confirm and 

 establish, as we have already seen in reference to the red 

 corpuscles, and as we shall immediately proceed to show in 

 relation to the white globules. 



While viewing the capillary circulation, it is easy to con- 

 vince oneself that no contraction of the parietes of the capil- 

 laries occurs, and that, therefore, the motion of the blood is 

 independent of any action of those vessels themselves, on 

 their contents. 



