The Microscope. <' 323 



forelegs, and after it has made an entrance, the blood flows free- 

 ly from the adjacent parts. 



The Louse. The louse has so transparent a shell, that we 

 are able to discover the circulation of the blood: the head has 

 two large black eyes; the legs, six in number, with hooked claws', 

 act as a thumb or finger; the body and legs are covered with hair. 

 It lays its eggs in human or other hair; these are what are gener- 

 ally called nits, and are worth while examining: they are stuck 

 on firmly to the hair with a glutinous matter. The young one 

 comes forth from the nit a perfect animal. We cannot wonder at 

 their increase, when one female will lay fifty eggs m a day, and 

 these come to life in six days. 



Spiders. Every one is acquainted with the general form of a 

 spider without the assistance of a microscope. We shall give a 

 description of the different parts of this insect which are only to 

 be discovered by it. As the fly, the spider's natural prey, is ex- 

 tremely cautious and nimble, it is necessary that the latter should 

 be able to look in all directions, and the number and disposition 

 of the eyes are wonderfully adapted forthis purpose; it has eight 

 eyes, and as it can not move its head, they are placed round it so 

 that it can see in all directions. The weapons that it uses to kill 

 its prey are well worthy of attention. They consist of a pair of 

 claws, or forceps, in the fore part of its head. It is hairy round 

 the mouth, and it has two rows of teeth. Spiders frequently cast 

 their skin, which may be found in cobwebs. The spider's web 

 is formed by a gummy liquor proceeding from the tail, which ad- 

 heres to any body that it presses against, hardens in the air, and 

 becomes a thread of so fine a texture, that it is calculated 

 that it would take ten thousand of them to make a single hu- 

 man hair. The eggs of the spider are curious objects, flat at 

 one end and a circle round them: the young spider comes 

 out perfectly formed. The egg, which the female guards 

 with the greatest care, is deposited in the web. The number of 

 eggs in one nest are several hundred. There are two or three 

 kinds, particularly worthy of notice: a small white field spider, 

 found among new hay; the leaping spider; another with two tufts 

 of feathers in its fore paws, and spotted; and a small red spider, 

 found on trees. The eyes, mouth, and legs, when examined with 

 the microscope, will be found most beautiful and interesting 

 objects. 



The Common Fly becomes an interesting object by dissect- 

 ing it, and placing the different parts under the microscope: the 

 body is covered with long hair; the head contains two large eyes, 

 and is one of the most curious objects under the microscope that 



