DIRECT INJURIES CAUSED BY INSECTS. 



65 



direct and indirect. By direct injuries I mean every species 

 of attack upon our own persons ; and by indirect, such as are 

 made upon our property. To the former of these T shall 

 confine myself in the present letter. 



Insects, as to their direct attacks upon us, may be arranged 

 in three principal classes. Those, namely, which seek to make 

 us their food ; those whose object is to prevent or revenge an 

 injury which they either fear, or have received from us ; and 

 those which indeed offer us no violence, but yet incommode 

 us extremely in other ways. 



1 hope I shall not too much offend your delicacy if I begin 

 the first class of our insect assailants with a very disgusting 

 genus, which Providence seems to have created to punish in- 

 attention to personal cleanliness. But though this pest of 

 man must not be wholly passed over, yet, since it is unfortu- 

 nately too well known, it will not be at all necessary for me 

 to enlarge upon its history. I shall only mention one fact 

 which shows the astonishingly rapid increase of these animals, 

 where they have once gotten possession. It is a vulgar notion, 

 that a louse in twenty-four hours may see two generations; 

 but this is rather overshooting the mark. Leeuwenhoek, 

 whose love for science overcame the nausea that such creatures 

 are apt to excite, proves that their nits or eggs are not hatched 

 till the eighth day after they are laid, and that they do not 

 themselves commence laying before they are a month old. 

 He ascertained, however, that a single female louse may, in 

 eight weeks, witness the birth of five thousand descendants.^ 

 You remember how wolves were extirpated from this country, 

 but perhaps never suspected any monarch of imposing a tri- 

 bute of lice upon his subjects. Yet we are gravely told that in 

 Mexico and Peru such a poll-tax was exacted, and that bags 

 full of these treasures were found in the palace of Monte- 

 zuma! ! !^ Were our own taxes paid in such coin, what little 

 grumbling would there be ! 



Two other species of this genus, besides the common louse, 

 are, in this country, parasites upon the human body. — But 



Leeuw. Epist. 98. 1696. 



2 Bingley, Jnim. Biogr. first edition, iii. 437. St. Pierre's Studies, &c. i. 312. 



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