PART II. 



DISEASE GERMS 



THEIR 



REAL NA TURE. 



]MONG the most fatal diseases from which 

 man and the higher animals suffer are those 

 which are called contagious or infectious. These 

 depend upon a poison, which, having entered the body, 

 grows and multiplies there in a marvellous manner 

 peculiar to matter which is alive. The living poison 

 may be introduced into our bodies in the air we 

 breathe, in the water we drink, or in the food we eat, 

 and may possibly also gain access to us by the pores 

 of the skin, or even by penetrating through the cuticle 

 itself. No care on our part will insure us against 

 invasion ; but, though surrounded by infection, and 

 living among contagious disease germs, it is by no 

 means certain that we shall be attacked, indeed the 

 probabilities of escape are very great. We might 

 wear water-proof coats and water-tight boots, cover 

 the head with mackintosh, protect the nostrils and 

 mouth with a cotton wool respirator, and grease or 

 varnish every particle of skin exposed, and, in spite of 



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