THE BLOOD. 67 



has in the first place vast importance, and in the second a 

 fundamental position in relation to all other parts. 



With this view of the subject, we have been in the habit, 

 and have found it a most profitable one to commence our 

 investigations in Anatomy, by first making a brief examin- 

 ation of this fluid as containing the primitive a'nd formative 

 element of the whole body. 



All the prominent and most important facts in relation 

 to the blood, of which we only propose to give as concise a 

 statement as possible, may be arranged under four heads: 



1st. The physical properties and relations of the blood. 

 2d. Its chemical properties and relations. 

 3d. Its microscopic properties and relations. 

 4th. Its vital properties and relations. 



When blood is drawn, we find it naturally separating into 

 two parts the one thick, called the crassamentum or clot 

 the other thin and fluid, the serum. 



The proportion which these bear to each other, is stated 

 to be four-fifths of clot, to one-fifth of serum. 



The crassamentum is the portion which forms the firm 

 solid mass by coagulation, and is colored, from containing 

 the red globules. 



The serum is the yellowish, transparent, watery part in 

 which the clot is seen to float. 



The blood, while circulating in the body, consists also of 

 two portions a solid and fluid the solid being the glob- 

 ules, while the fluid is called the liquor sanguinis, which 

 holds both crassamentum and serum in solution. 



The Liquor sanguinis, or plasma, is described as a pale 

 and clear fluid, containing the corpuscles, and when drawn, 

 presents as its striking characteristic, a disposition to co- 

 agulate. 



During coagulation, the corpuscles are retained, but can 

 be separated by the filter, as recommended by Muller. 



In inflammatory diseases the red corpuscles subside before 

 coagulation occurs, leaving the upper portion of the blood 



