92 ORGANISED FLUIDS. 



the seat of colour, while the great organic development and 

 the functional and mental activity depend partially upon the 

 greater amount of oxygen of which the blood corpuscles are 

 the carriers to all parts of the system, and which is so essen- 

 tial to the vigorous performance of the vital processes and 

 manifestations. 



The characters exhibited by* blood which has been with- 

 drawn from the system are likewise consistently explained 

 by reference to the augmented quantity of the red blood 

 corpuscles ; thus the blood in plethora, immediately on its 

 abstraction, is observed to be of a deeper colour, and the clot 

 formed subsequently by its coagulation of a larger size ; this, 

 although voluminous, is of mean density, and never exhibits 

 the buffy coat, which circumstances are accounted for by the 

 fact that, as already remarked, in the blood of plethoric per- 

 sons there exists necessarily no excess of fibrin. 



Accompanying the plethoric condition, and dependent 

 upon it, we have frequently a number of grave pathological 

 manifestations, apoplexies, haemorrhages, congestions, vertigos, 

 noises in the ears, and flashes of light before the eyes ; all of 

 which are most generally greatly relieved by venesection, 

 which withdraws from the system a portion of the super- 

 abundant red blood corpuscles. 



Decrease in the Number of the Red Corpuscles. Ancemia. 



The term anaemia indicates a state of the system the 

 very reverse of that which obtains in plethora: in it the 

 red blood corpuscles, instead of being in excess, are greatly 

 below the physiological standard. The authors quoted found, 

 in sixteen cases of commencing anaemia, the mean of the red 

 globular element of the blood to be 109; and in twenty-four 

 examples of confirmed anaemia, 65; that is, almost one-half less 

 than the standard which belongs to health. In one case of 

 anaemia in the human subject, M. Andral found the scale to 

 descend so low as 28 ; a depression which one would scarcely 

 suppose to be compatible with life. 



In spontaneous anaemia it is stated, that it is the globules 



