304 



THE SNAKES OF SOUTH AFRICA. 



and larger 13'mphatic vessels, until at last it is poured through 

 two big tubes in the neck into two large veins, and thence to 

 the heart to be pumped, along with the venous or impure blood, 

 into the lungs to get rid of its load of poison. 



How Snake Venom is Sucked up. 



This vast network of absorbent lymphatic vessels and capil- 

 laries, which spread out under the skin, and in all directions 



I'iG. 129. — This drawing serves to show how an artery breaks up into 

 small channels which are called capillaries. They are so small that 

 they cannot be seen except with a microscope. After nourishing the 

 cells, they run together again, and form what is known as a vein. 

 The little bodies in the spaces are the cells of the tissues. They are sur- 

 rounded by lymph. The black lines are the Lymphatics which have open 

 mouths to suck up the lymph and all it might contain, and carry it away 

 to the blood. 

 A. Artery. V. Vein. L. Lymphatics. 



through the tissues of the body, sucks up any fluid which may be 

 injected, or otherwise find its way under the skin, or into 

 the muscles. Drugs are frequently administered thus. They 

 find their way more rapidly and efficiently into the general 

 circulation when hypodermically injected, than if swallowed. 



Ordinary cases of blood poisoning occur in this manner. The 

 poison is sucked up from the wound. Microbes of various 

 diseases gain an entry into the blood also in this manner, hence 

 the reason why all wounds, and even slight abrasions of the 



