252 THE BLOOD. 



defibrinated blood which separates is sometimes called cruor l and con- 

 sists of blood-corpuscles and blood-serum, while uncoagulated blood 

 consists of blood-corpuscles and blood-plasma. The essential chemical 

 difference between blood-serum and blood-plasma is that the blood- 

 serum does not contain even traces of the mother-substance of fibrin, 

 the fibrinogen, which exists in the blood-plasma, while the serum is pro- 

 portionally richer in another body, the fibrin ferment (see below). 



I. BLOOD-PLASMA AND BLOOD-SERUM. 

 The Blood-plasma. 



In the coagulation of the blood a chemical transformation takes 

 place in the plasma. A part of the proteins separate as insoluble fibrin. 

 The albuminous bodies of the plasma must therefore be first described. 

 They are, as far as we know at present, fibrinogen, nucleoprotein, ser- 

 globulins, and seralbumins. 



Fibrinogen occurs in blood-plasma, chyle, lymph, certain transudates 

 and exudates, in bone-marrow (P. MULLER), and perhaps also in other 

 lymphoid organs. The seats of formation of fibrinogen are, according 

 to MATHEWS, the leucocytes, especially of the intestine, according to 

 MULLER, the bone-marrow and probably other lymphoid organs such 

 as the spleen and lymph glands, and according to DOYON and NOLF, 

 the liver. The statement that the intestinal wall is a seat of formation 

 of fibrinogen, a view that had been held by DASTRE, is substan- 

 tiated not only by the direct researches of MATHEWS, but also by the 

 older and substantiated opinion that the blood from the mesentery vein 

 is richer in fibrinogen than the arterial blood. This origin of fibrinogen 

 has been shown to be improbable by the recent researches of DOYON, CL. 

 GAUTIER and MOREL. The occurrence of fibrinogen in the bone-marrow 

 and other lymphoid organs as shown by MULLER, and an increase of 

 fibrinogen in the blood as well as in the bone-marrow of animals immunized 

 with certain bacteria, especially pus-staphylococci, indicates the forma- 

 tion of fibrinogen in this tissue. The relation between the quantity of 

 fibrin and leucocytosis as shown by many investigators such as LANG- 

 STEIN and MAYER, MORAWITZ and REHN, also indicate such a formation 

 of fibrinogen. The observations of DOYON, GAUTIER and MA WAS that 

 a rapid re-formation of fibrinogen takes place in splenectornized animals 



1 The name cruor is used in different senses. We sometimes mean thereby only 

 the blood when coagulated in a red solid mass, in other cases the blood-clot after the 

 separation of the serum, and again the sediment consisting of red blood-corpuscles 

 which is obtained from defibrinated blood by means of centrifugal force or by letting 

 it stand. 



