CHAPTER VII 



THE CIRCULATION 



The Blood Its Plasma and Corpuscles Coagulation of the Blood 

 The Uses of the Blood Transfusion Change of Color The Organs 

 of the Circulation The Heart, Arteries, and Veins The Cavities 

 and Valves of the Heart Its Vital Energy Passage of the, Blood 

 through the Heart The frequency and Activity of its Movements 

 The Pulse The SpygmographThe Capillary Blood-vessels The 

 Bate of the Circulation Assimilation Injuries to the L'^od-vessels 

 E/ects of Alcohol on Heart 



1. The Blood. Every living organism of the higher sort, 

 whether animal or vegetable, requires for the maintenance of 

 life and activity, a circulatory fluid, by which nutriment is dis- 

 tributed to all its parts. In plants, this fluid is the sap ; in 

 insects, it is a watery and colorless blood; in reptiles and 

 fishes, it is red but cold blood; while in the nobler animals 

 and man, it is red and warm blood. 



2. The blood is the most important, as it is the most abun- 

 dant, fluid of the body ; and upon its presence, under certain 

 definite conditions, life depends. On this account it is fre- 

 quently, and very properly, termed "the vital fluid." Tne 

 importance of the blood, as essential to life, was recognized in 

 the earliest writings. In the narration of the death of the 

 murdered Abel, it is written, "the voice of his blood crieth 

 from the ground." In the Mosaic law, proclaimed over thirty 

 centuries ago, the Israelites were forbidden to eat food that 

 contained blood, for the reason that " the life of the flesh is in 

 the blood." With the exception of a few tissues, such as the 

 hair, the nails, and the cornea of the eye, blood everywhere 

 pervades the body, as may be proved by puncturing any pan 



1 . What is required by every living organism ? In plants ? Insects ? Keptiles ? Man ? 



2. Importance and abundance of blood ? Dependence of life ? Abel ? Mosaic law ? 

 In what part of the body is blood not found ? Quantity of blood in the body f 



