THE CAPILLARY VESSELS. 5 
with furious speed, crimsoning the face with hot blushes ; or another cause the vital fluid 
to recoil to the heart, leaving the countenance pallid, the eyes vacant, and the limbs cold 
and powerless, as if the very life had departed from the body. 
Not without reason do the earlier Scriptures speak so reverently of the blood, 
accepting the outpoured life of beasts as an atonement for the sin, and witness of the 
penitence of man, and forbid its use for any less sacred office. Nor was it without 
a still mightier meaning that the later Scriptures endue the blood with a sacramental 
sense, giving even to its vegetable symbol, the blood of the grape, a dignity greater than 
that of the former sacrifices. 
A few words must also be given to the mode by which the blood is kept continually 
running its appointed course through the animal frame. This process, commonly called 
CIRCULATION, takes place in the following manner, Man being an example :— 
In the centre of the breast lies the. heart, an organ composed of four chambers, the 
two upper being termed auricles, and the two lower being distinguished by the title of 
ventricles. These are only conventional terms, and do not express the office of the parts. 
The auricles are comparativel y slight in structure, but the ventricles are extremely 
powerful, and contract with great force, by means of a curiously spiral arrangement 
of the muscular fibres. These latter chambers are used for the purpose of propelling the 
blood through the body, while the auricles serve to receive the blood from these vessels, 
and to throw it into the ventricles when they are ready for it. 
By the systematic expansion and contraction of the heart-chambers, the blood is sent 
on its mission to all parts of the body, through vessels named arteries, gradually 
diminishing in diameter as they send forth their branches, until they terminate in 
branchlets scarcely so large as hairs, and which are therefore called “ capillaries,” from 
the Latin word capillus, a hair. The formation of the capillary system is well shown 
ims 
Di 
Ss 
tu/ 
CAPILLARIES IN SKIN OF CAPILLARIES OF HUMAN 
HUMAN FINGER. TONGUE. 
CAPILLARY. 
by the accompanying sketches. The first figure exhibits a portion of capillaries which 
are found in the fatty tissues, while the second and third are examples of the corre- 
sponding vessels in the finger and the tongue. 
In the capillaries the blood corpuscules would end their course, were they not met 
and welcomed by a second set of capillaries, which take up the wearied and weakened 
globules, carrying them off to the right-hand chambers of the heart, which impel them 
through vessels known by the name of “veins,” to be refreshed by the air which is 
supplied to them in the beautiful structure known as the lungs. Meeting there with 
fresh vitality—if it may so be called—the blood corpuscules throw off some of their effete 
portions, and so, brightened and strengthened, are again sent from the heart to run their 
round of existence. 
It is indeed a marvellous system, this constant circular movement, that seems to be 
inherent in the universe at large, as well as in the minute forms that inhabit a single 
orb. The planets roll through their appointed courses in the macrocosmal universe, us 
