200 NATURAL HISTORY. [ctt. XI, 



nowever, like that of the queen of the white antg» 

 the cocci, &c., enlarges to an enormous size when 

 full of young. 



A greater abomination than any of these is the 

 louse. It is said that on the third day of the disease 

 called plica Polonica, in which the hair of the head 

 becomes painful and distended with blood so as to 

 drain the patient if cut, they appear in myriads. 

 Leuwenhoek has calculated that a female lays at 

 least sixty eggs in six days ; that in six days more 

 the young appear ; that in eighteen days more they 

 are capable of propagating; so that, according to 

 his calculation, two families of lice would, in sixty 

 days, have fifteen thousand descendants. 



Since the days of Pharaoh, Herod, Scylla, and 

 Philip II., these horrid infesters of our race, three 

 species of which attach themselves as parasites to 

 man, have given a name to a disease, which, though 

 extremely rare, is not fictitious — the phthiriasiSj or 

 morbus pedicularis. 



The mite tribe {acari) is another class of insects, 

 which sometimes cause the most horrible maladies 

 to man. They are oviparous, and those which 

 swarm in rotten cheese will give a correct notion of 

 the general form of the whole class. Heberden and 

 Willan, in modern times, have recorded dreadful in- 

 stances of the sufferings which they have inflicted 

 upon the human race. They penetrate under the 

 skin, and multiply in little tumours, which, when 

 opened, swarm with these creatures. Mouffet states 

 of the Lady Penruddock, that mites swarmed on 

 every part of her body ; on the eyes, nose, gums, 

 head, soles of the feet, putting her to daily and 

 nightly torture ; so that all the flesh of her body 

 being consumed, she at length had the happiness to 

 die! 



It has been also asserted that the itch is caused 

 by the presence of a mite. The insect, says Lin- 

 naeus, insinuates itself under the skin, and there 



