3&4 INVERTEBRATES. 



pain, and his life was supposed to be in danger ; however, he reco- 

 vered by the application of roasted onions to the part, and was 

 «oon quite well. Of this animal there are different kinds ; some 

 living, like worms, in holes in the earth ; others under stones an;? 

 among rotten wood; so that nothing is more dangerous than* 

 removing those substances, in the places where they breed. 



The Louse has neither beak, teeth, nor any kind of mouth, 

 as Dr. Hooke described it, for the entrance into the gullet is abso- 

 lutely closed. In the place of all these, it has a proboscis oi 

 trunk, or, as it may be otherwise called, a pointed, hollow sucker, 

 with which it pierces the skin, and sucks the human blood, taking 

 that for food only. The stomach is lodged partly in the breast 

 and back; but the greatest portion of it is in the abdomen. 

 When swollen with blood, it appears of a dark brown color, which 

 is visible through the skin, and is either a faint red, or a full or 

 bright brown, as the contents of the stomach are more or less 

 changed. When it is empty it is colorless; but when filled it is 

 plainly discernible, and its motion seems very extraordinary. It 

 then appears working with very strong agitations, and somewhat 

 resembles an animal within an animal. Superficial observers are 

 apt to take this for the pulsation of the heart; but if the animal 

 be observed when it is sucking, it will then be found that the food 

 lakes a direct passage from the trunk to the stomach, where the 

 remainder of the old aliment will be seen mixing with, the new, 

 and agitated up and down on every side. 



If this animal be kept from food two or three days, and 

 then placed on the back of the hand, or any soft part of the body, 

 it will immediately seek for food ; which it will the more readily 

 find, if the hand be rubbed till it grows red. The animal then 

 turns its head, which lies between the two fore legs, to the skin, 

 and diligently searches for some pore. When found, it fixes the 

 trunk therein, and soon the microscope discovers the blood 

 ascending through the head, in a very rapid and even frightful 

 stream. The louse has, at that time, sufficient appetite to feed in 

 any posture — it is then seen sucking, with its head downward and 

 its tail elevated. If, during this operation, the skin be drawn 



