300 



THE SNAKES OF SOUTH AFRICA. 



thus benumbed, and rendered incapable of killing off disease 

 microbes, which multiply and cause a disease peculiar to their 

 species or kind. If you disregard the laws of eating and drinking 

 then you should not blame Providence if the machinery of your 

 body gets out of gear, and disease microbes attack it. 



How TO Keep your Blood Pure. 



The first essential is to breathe plenty of oxygen, and inhale 

 deeply. A great many people get into the habit of breathing 



in a very shallow way, inflat- 

 ing only a portion of their 

 lungi. Boys and girls who 

 have flat chests should be 

 compelled to take systematic 

 club, dumb-bell, or other suit- 

 able physical exercises for en- 

 larging the chest and lung 

 capacity. The exercises should 

 not be discontinued until the 

 chest becomes convex. 



Practise deep breathing 

 until it becomes a habit. Sit 

 in a chair with a straight back, 

 bolt upright. Slowly breathe 

 as much air into your lungs as 

 you are able to force down. 

 Retain it till you count five, 

 then slowly exhale it. Con- 

 tinue this for fifteen minutes, 

 twice a day if possible. At 

 first you will feel a trifle 

 giddy with the unaccustomed 

 amount of blood which gets 

 into your lungs, but this soon 

 wears off. Breathe through 

 your nose. It is a microbe 



Fig. 127. Rough diagram showing liow the 

 blood circulates through the body. Poison- 

 laden blood runs to the heart from all 

 over the body. It is then pumped into 

 the lungs and puriiied by the air we 

 breathe. It returns to the heart to be 

 again pumped to the remotest corners of 

 the body. (From Blackie's Physiology.) 



and dust filter, and warms the air also. 



