THE TYRANNY OF PARASITES 333 



disease — to which all our infective fevers are due— we 

 have only become aware quite recently, within the half- 

 century. Before they were known, cleanliness and the 

 destruction of putrescible matter in man's surroundings 

 had, it is true, been urged by sanitary reformers. Dis- 

 infectants and antiseptics were deliberately made use 

 of for this purpose in the mid-Victorian period, when 

 carbolic acid and chlorinated lime were established in the 

 place of those feebler destroyers of the germs of putre- 

 faction and disease — namely, the extracts of aromatic 

 herbs or the essential oils themselves. These, as perfumes 

 and unguents, really served, not merely to gratify the 

 olfactory sense, but to destroy by their chemical action 

 the germs of disease. Men tolerated gnats and their 

 bites (mosquitoes as we prefer to call them in order to 

 delude ourselves into the belief that they are not British) 

 until it was discovered that they, and they only, carry the 

 parasitic germs of two deadly diseases — malaria, or ague, 

 and yellow fever. Now we shall destroy the pools in 

 which they breed, just as we are destroying the manure 

 heaps in which the house-fly breeds. When we look over 

 the list it is really astonishing how much remains to be 

 done, even in England, in establishing increased clean- 

 liness and freeing ourselves from the murderous tyranny of 

 parasites. It is a simple but horrible fact that the poorest 

 class in our big cities still swarms with vermin. And not 

 pnly are the poor in great cities thus afflicted. The recent 

 compulsory medical inspection of school children has 

 shown that in some of the smiling rural districts of 

 England 80 per cent, of the children have lice in their 

 heads. Everyone should help to gain further cleanliness 

 and freedom from this form of oppression. 



In the middle of the nineteenth century, England alone, 

 and with absolute conviction and determination, demon- 

 strated to the civilised world the beneficial results in 



