292 THE SNAKES OF SOUTH AFRICA. 
the food which may have escaped perfect digestion by the other 
fluids. Then the food is ready to be taken up and converted 
into blood. In the inner walls of the bowels there are millions 
of tiny mouths, which greedily suck up the digested food. These 
little suckers are called lacteals. There is another set known 
as venous absorbents. Some of the absorbed food is carried 
to the liver to be filtered and purified before finding its way into 
the blood stream. The portion which does not need to be acted 
upon by the liver, is carried through a long slender tube known 
as the thoracic duct, and poured into a large vein. 
CONVERTED INTO BLOoop. 
The liquid food mingles with the venous blood and eventually 
pours into the right side of the heart, and is pumped up into the 
lungs. Here a marvellous change takes place. The air we 
breathe contains a large amount of oxygen, if it be fresh and pure. 
This oxygen gas instantly combines with the venous blood, 
and a lightning-like chemical change takes place. The food 
is changed into living blood, which is made up of tiny discs 
known as corpuscles, which float in a fluid substance we call 
serum. The blood is then returned to the heart, but this time 
to the left half. From here it is pumped all over the body 
through vessels known as arteries. These divide and subdivide 
until they become mere threads, so tiny that they are invisible 
to the naked eye. These are known as capillaries. So numerous 
are they that you cannot prick your flesh anywhere with the 
finest needle-point without rupturing several of them. 
HEALTH LAWS. 
There are laws governing every department of Nature. To 
disobey any of these natural laws means punishment in some 
shape or form. These laws work automatically. Whether 
violated wilfully or ignorantly the punishment is the same. 
There is no escape. We may perhaps escape the consequences 
of the breaking of man-made laws, but not the laws of God. 
They are self-acting. 
Science is finding out more about these great natural laws, and 
how they work. In proportion to our knowledge of the workings 
