HUMAN PHYSIOLOGY. 



CHAPTER I. 



THE BLOOD. 



Quantity of blood General characters of the blood Blood-corpuscles Development of the blood-corpus- 

 cles Leucocytes Development of leucocytes Blood-plaques Composition of the red corpuscles 

 ' Globuline Haemaglobine Composition of the blood-plasma Inorganic Constituents Organic saline 

 constituents Organic non-nitrogenized constituents Excrementitious constituents Organic nitrogen- 

 ized constituents Plasmine, fibrin, metalbumen, serine Peptones Coloring matter Coagulation of 

 the blood Conditions which modify coagulation Coagulation of the blood in the organism Cause of 

 the coagulation of the blood. 



WITH the progress of knowledge and the accumulation of facts in physi- 

 ology, the importance of the blood in its relations to the phenomena of ani- 

 mal life becomes more and more thoroughly understood and appreciated. 

 The blood is the most abundant and highly organized of the fluids of the 

 body, providing materials for the regeneration of all parts, without excep- 

 tion, 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 regeneration of the nutritive constituents of the 

 blood, and on the other, its constant purification 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 pene- 

 trated by vessels, are none the less dependent upon the blood, as they imbibe 

 nutritive material from the blood of adjacent 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 dem- 

 onstrated by experiments upon the inferior animals. If, in a small dog, a 

 canula adapted to a syringe be introduced through the right jugular vein 

 into the right side of the heart, and a great part of the blood be suddenly 

 withdrawn from the circulation, immediate suspension of all the so-called 

 vital processes is the result ; and if the blood be then returned to the system, 

 the animal is as suddenly revived. 



Certain conditions, 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 



