THE BLOOD. 



199 



or coagulum, but it is not true fibrin, since it is a combination of 

 fibrinogen with lime. 



Nucleo-proteid of Plasma. About the only characteristic that 

 is known in connection with the nucleo-proteid is that it is very 

 essential to the formation of fibrin during coagulation. It is formed 

 by the dissolution of the leucoc}^tes and blood-plates after the blood 

 is shed from the body. When hydrocele, pericardial, and ascitic 

 fluids contain no leucocytes, it has been noticed that they lack power 

 of spontaneous coagulation. The nucleo-proteids in the presence of 

 calcium salts form a substance which is identical in every respect 



Fig. 61. Delicate Fibrin Coagulum (from Croupous Pneumonia.) 

 X 350. (LENHAETZ.) 



with the fibrin-ferment of Alexander Schmidt. This new substance 

 possesses the power of converting fibrinogen into fibrin. 



THE NONPROTEIDS OF THE PLASMA. The nonproteids comprise 

 both nitrogenous and nonnitrogenous elements. 



The nonnitrogenous consist of carbohydrates and fats, with 

 small amounts of lipochrome and sarcolactic acid. 



The nitrogenous elements comprise in their category urea, uric 

 acid, hippuric acid, creatin, and some ferments. 



Urea, which represents the end-product of nitrogenous combus- 

 tion of the tissues must be included among the normal elements of 

 this fluid. It is found in the blood in small proportion. But it can 

 accumulate in an abnormal manner within the blood. It is in this 

 way that ablation of the kidneys, acute nephritis, and the terminal 



