LICE. 391 



CASE conjunctiva, and in the ears. The appHcation of those external 

 remedies, which readily destroy the common species of Pediculi, 

 failed entirely in extirpating these : a variety of internal means 

 were likewise used unavailingly, and the insects were not admitted 

 to be sensibly diminished in number at the time of my quitting 

 Devonshire." 



The reader, no doubt, recollecting what we have already said 

 on some of the acaroid diseases, will be able for himself to 

 eUminate from the above what is essential, and what is doubtful, 

 irrelevant, and accidental. Such cases only occur in private 

 practice, and usually in the country. If the lady had been 

 brought to a London hospital, we would undertake to say that 

 everything mysterious would immediately have vanished, and the 

 patient would have been discharged cured in a week. 



Genus Pediculus [Lm7i.), True Lice. 



No one can examine the figures of the Haematopini above given 

 without seeing that they are exceedingly close to the Pediculi, 

 so much so that that of the monkey might almost be equally 

 well placed in either genus. We need not discuss whether more 

 than one genus should be made for them, but a more interesting 

 question, viz., whether different species of lice are appropriated to 

 different races of men, can hardly be passed over without a word 

 or two of consideration. The interest of the point lies in its 

 bearing on another vexed question, the unity of the human race, 

 on which it may throw some light. On the one hand it is main- 

 tained by those who are of opinion that all men are not of the 

 same species that the parasites which infest the different races of 

 man are distinct ; and because we usually find that distinct species 

 of parasites are allotted respectively to the different species of the 

 lower animals, they infer that the same rule must hold with man, 

 and that therefore each different race possessing a distinct 

 parasite must be a distinct species. Their opponents, on the 



