HUMAN PHYSIOLOGY. 



CHAPTER I. 



THE BLOOD. 



General considerations Transfusion Quantity of blood General characters of the blood Blood-corpuscles 

 Development of the blood -corpuscles Leucocytes Development of leucocytes Composition of the red cor- 

 puscles Globuline Haemaglobine Analysis of the blood Composition of the blood- plasma Inorganic prin- 

 ciples Organic saline principles Organic non-nitrogenized principles Excrementitious matters Organic nitro- 

 genized principles Plasmine, fibrin, metalbumen, and seriue Peptones Coloring matter Coagulation of the 

 blood Characters of the clot Characters of the serum Circumstances which modify coagulation Coagulation 

 of the blood in the organism Spontaneous arrest of haemorrhage Cause of the coagulation of the blood So- 

 called fibrin-factors Paraglobuline, or fibrinoplastic matter Fibrinogen. 



FROM the earliest periods in the history of physiology, the importance of the blood 

 has been recognized ; and, with the progress of knowledge, this great nutritive fluid has 

 been shown to be more and more intimately connected with the phenomena of animal 

 life. It is now known to be the most abundant and highly organized of the fluids of the 

 body, providing materials for the regeneration of all parts, without exception, receiving 

 the products of their waste and conveying them to proper organs, by which they are 

 removed from the system. These processes require, on the one hand, constant regen- 

 eration of the nutritive constituents of the blood, and, on the other, its constant purifi- 

 cation by the removal of effete matters. 



Those tissues in which the processes of nutrition are active are supplied with blood 

 by vessels; but some, less highly organized, like the epidermis, hair, cartilage, etc., 

 which are called extra-vascular because they are not penetrated by vessels, are none the 

 less dependent upon the blood, as they imbibe nutritive material from the blood of ad- 

 jacent parts. 



The importance of the blood in the processes of nutrition is evident ; and, in animals 

 in which nutrition is active, death is the immediate result of its abstraction in large 

 quantity. Its importance to life can be readily demonstrated by experiments upon the 

 inferior animals. If we take a small dog, introduce a canula through the right jugular 

 vein into the right side of the heart, adapt to it a syringe, and suddenly withdraw a great 

 part of the blood from the circulation, immediate suspension of all the so-called vital 

 processes is the result. If we then return the blood to the system, the animal is as sud- 

 denly revived. To perform this experiment satisfactorily, we must accurately adjust the 

 capacity of the syringe to the size of the animal. 



Certain causes, one of which is diminution in the force of the heart's action after 

 copious haemorrhage, prevent the escape of all the blood from the body, even after 

 division of the largest arteries; but, after the arrest of the functions which follows 

 copious discharges of this fluid, life may be restored by injecting into the vessels 

 the same blood or the fresh blood of another animal. This observation, which was first 

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