SOME HUMAN PARASITES 307 



LICE PARASITIC ON MAN 



Pediculus humanus et al. 



There are three species of lice, the head louse, body 

 louse, and crab louse, parasitic on the body of man. All of 

 these species have been associated with man as long as we 

 have any history of the human family. Some of the forms, 

 at least, are referred to in the writings of Herodotus and 

 Aristotle. Many of the oldest naturalists, Swammerdam, 

 Linnaeus, Redi, and others, have given lengthy disserta- 

 tions on the head louse. The presence of these lice on the 

 body of human beings did not seem to be a matter of so 

 much consequence in the older days, for instance, in the 

 days of the Stuarts, as it is nowadays. Cleanly people 

 to-day would be very much horrified and disgusted to find 

 one of these lice on their persons. In the olden times, 

 however, these creatures were joked about and even 

 tolerated on one's person. It is said that they were 

 boasted of by some people. 



In an old book entitled " Micrographia, " published by 

 R. Hooke of London in 1665, there is a description of the 

 head louse which is introduced as follows : " This is a 

 creature so officious that 'twill be known to every one at 

 one time or other, so busie, and so impudent, that it will 

 be intruding itself in every one's company, and so proud 

 and aspiring withall that it fears not to trample on the 

 best, and affects nothing so much as a crown ; feeds and 

 lives very high, and that makes it so saucy as to pull any 

 one by the ears that comes its way, and will never be quiet 

 till it has drawn blood." 



These lice may pass directly from one person to another 



