THE BLOOD AND ITS FUNCTIONS 131 



perhaps, makes an examination of the blood and finds that he 

 has anosmia, and that the blood contains too few red corpus- 

 cles. Now, while in this case it is true that the trouble shows 

 itself in the blood, the real cause is not there, but in those 

 parts of the body where the red corpuscles are formed, 

 and which for some reason are not making them rapidly 

 enough. Suppose again the paleness to be due to too many 

 white corpuscles,. Here too, while the most noticeable 

 feature is in the blood, the real cause is in some of the other 

 organs whose impaired functions result in increasing the 

 numbers of white corpuscles until they are altogether too 

 numerous. The physician's treatment should be directed to 

 the real source of the trouble, not to the blood itself. 



Blood Poisoning. Blood poisoning is a name given to a 

 series of troubles caused by a certain kind of bacteria which 

 get into the body and multiply rapidly. The 

 poisoning agents are commonly in the skin, 

 muscles, glands or some other active organ, not 

 often in the blood itself; but in some forms of 

 the disease the blood carries them through the 

 body and hence the name blood poisoning arises. 

 The germs which cause the trouble (Fig. 70) 

 are abundant everywhere, in the air, in the soil, rp HE BAC _ 

 on our clothes, on our skin, etc. They do no TE RIA THAT 

 harm, unless they penetrate the skin by way of a PRODUCE 

 cut or bruise; and even then they do not often VARIOUS 



cause trouble, for our bodies are wonderfully 



, . ' . , . . , ~ BLOOD POI- 



endowed with power for resisting them. Com- s N x N G 



monly, therefore, they either do us no injury or BOILS ETC. 

 produce simply a slight pimple, a little festering a, streptococci- 

 sore or a boil. If the body is in good condition, ^^ 

 the white corpuscles attack the bacteria in 

 these sores, and with the help of other resisting agencies the 

 germs are destroyed and the sore heals. But in other cases, 

 either where the resistance of the body is very weak or the 





