CHAP. XXVII.] MORBID BLOOD. 311 



density, but upon this point observers are very far from being 

 agreed ; and also as to the proportions of solid constituents, but on 

 this subject likewise the reports of analysts are contradictory and 

 highly unsatisfactory. 



The blood of the vena porta is said by F. Simon to coagulate 

 more slowly and less perfectly than ordinary venous blood ; it con- 

 tains less fibrine and much more fat. 



Influence of Venesection and of Disease upon the Blood. The 

 influence of venesection, and of some morbid states upon the rela- 

 tive quantities of these constituents of the blood, deserves to be 

 well impressed upon practitioners. 



Venesection, or the loss of blood by any means, reduces the 

 amount of the red particles chiefly, and the more so in proportion 

 to its frequency ; the serum is diminished in density, and the quan- 

 tity of the albumen and the fat is slightly reduced ; that of fibrine 

 is not affected, nor are the extractives and salts. 



The following cases from Dr. Christison illustrate the influence of 

 venesection upon the blood. 



The first is that of a middle-aged woman, who had been pre- 

 viously repeatedly bled for palpitations of the heart. The analysis 

 of her blood gave the following result : 



Fibrine . . . . , . 2 



Solids of serum . . . . 76 



Ked particles . . . " . 57 



Water . . ..." V 863 



In the second case there had been frequent bleedings after 

 rheumatism. 



Fibrine 4 



Solids of serum . . . 93 



Red particles . . . , 57 



Water 844 



This latter case shows how impotent is venesection, even when 

 carried to a great extent, over the reduction of fibrine, the material 

 that forms those new deposits of organizable matter of plastic 

 lymph, which in inflammations of internal organs, such as the 

 lungs and heart, so much interfere with the normal action. 



The following experiment, also, illustrates the effects of venesec- 

 tion upon the blood, first, when the animal was well fed at the time 

 when the bleedings were being practised; and, secondly, when it 

 was starved between the operations. 



A large dog was fed upon two pounds of meat, and a quart of 

 milk a day, and six ounces of blood were drawn on each of four 



