NUTRITION. 



79 



The mean proportion of these diflerent ingredients in a thousand 

 parts of blood may be thus stated: Fibrine^ 3 parts; Albumen, S() 

 parts; Red Corpuscles, 127 parts; Water and Salts, 790 parts. 

 These proportions are subject to considerable variations within the 

 hmits of health. There is also a small amount of fatty matters and 

 extractive. The following is the analysis of Simon made upon 

 the blood of males: Water, 791-9; Fibrine, 2-0 ; Corpuscles, 114-3 

 Albumen, 75-6 ; Extractive Matters and Salts, 14*2 ; Fatty Mat- 

 ters, 2-0. There is a greater amount of solid matter in the blood 

 of the male than of the female, except in the case of albumen, which 

 is in larger quantity in the female. 



Each of the prominent constituents' of the blood has been already 

 described in the earlier pages of these divisions, to which the reader 

 is referred. 



When the blood is examined shortly after a meal the serum is 

 found to present a milky appearance. According to Drs. Buchanan 

 and R. D. Thompson this appearance is due to the admixture of the 

 chyle. The period at which the discoloration is greatest, however, 

 and the length of time during which it continues, vary according 

 to the kind and quality of the food, and the state of the digestive 

 functions. The milkiness seems to be entirely due to the presence 

 of oleaginous matter in the food. The crassamentum of such blood 

 often exhibits a pellucid fibrinous crust, sometimes interspersed with 

 white dots ; and this seems to consist of an imperfectly assimilated 

 proteine compound, analagous to that found in the serum. A small 

 quantity of sugar is occasionally found, even in healthy blood, when 

 large quantities of it are taken as food. But commonly it is trans- 

 formed into lactic acid, or into fatty matter, before it is received into 

 the circulating current. 



By some high authorities the coagulation of the blood is looked 

 upon as a mere physical process, dependent upon the exposure of the 

 fluid to the air, precisely as some chemical substances are known to 

 solidify under similar circumstances ; and the long delay of the 

 coagulation after death is mentioned as confirmatory. By others it 

 is contended that the coagulation is the last act of vitality of the 

 blood, which is evident from the incipient organization which may 

 be detected even in an ordinary clot ; and still more from the fact, 

 that if the effusion of fibrine take place upon a living surface, its 

 coagulation in the first act of its conversion into solid tissues posses- 

 sing a high degree of vitality. If not within the influence of a 

 living surface, it soon passes into a state of decomposition. 



The rapidity of the coagulation depends very much upon the 

 circumstances in which the blood is placed. It is accelerated by 

 moderate heat, and retarded, though not prevented by cold. The 

 blood that flows last from a vessel coagulates more rapidly, but less 

 firmly, than that first drawn ; and in inflammatory blood, in which 

 the fibrine is increased, coagulation is unusually slow. 



