110 NORTH AMERICAN INSECTS. 



order. The other parasites, which live upon beasts, 

 birds, fishes and insects, and which are also called 

 by the people, lice, belong to different other orders, of 

 which I shall speak in some of the following numbers. 



Many years ago, when people paid very little atten- 

 tion to personal cleanliness, it was generally believed 

 to be a sign of good health to be infected with lice, 

 by whom it was thought the impure juices of the 

 body were extracted. Parents were, on that account, 

 glad to see the heads of their children covered with 

 sores, which were thickly populated with this vermin. 

 Bat when they became better instructed, and began 

 to keep their children clean, these insects ceased 

 to be fashionable. For this purpose it is probable 

 that hair-powder, pomatum, and hair-oil were chiefly 

 invented, and generally used, because every kind of 

 grease destroys these insects, by stopping up their 

 air-holes or breathing organs, and they immediately . 

 fall into convulsions and die. An experiment that 

 may be repeated at pleasure on caterpillars. 



These disgusting creatures make their abode prin- 

 .cipally upon the heads of human beings, as may be 

 -(■en, for instance, in the haunts of the filthy poor 

 everywhere, or the poor oppressed Jews and peasants 

 of Poland, or the down-trodden and degraded country- 

 men of Italy, and the innumerable; host of beggars 

 with which all her churches swarm. 



