256 THE MICROSCOPE AND ITS LESSONS. 



also altered ; but much remains yet to be discovered. The 

 nerves of insects do not originate in a brain as in the 

 higher order of animals, but in numerous nerve-bundles, 

 as seen in our dissection of the caterpillar of a silkworm 

 moth. What is the exact seat of their sense of hearing 

 or smelling we do not at present know ; their organs of 

 digestion are very simple; that most important of all 

 their little bodily parts, the circulation, is more easily 

 observed and appears to flow very regularly, and in many 

 parts of the body, as in spiders, with a distinct pulsation. 

 Remember that, very distinctly, are the organs of respira- 

 tion to be seen, for they communicate with the air by 

 means of coils of spiral tubing, having sieve-like openings, 

 or spiracles, very similar to the trachea and spiracle of 

 plants, and being evidently formed for the same purpose. 

 Your entomological studies will "do little for you if 

 they do not suggest to you some of those great expec- 

 tations which belong to the consideration of a future life. 

 I wish to keep you constantly in mind of this, because 

 my own life has been so very greatly benefited and blessed 

 with the thought. You will be delighted in examining 

 the wonders of moths and butterflies. Think, for example, 

 of the wisdom given to the White Admiral butterfly. It 

 deposits its eggs, which are almost exactly like the shell 

 of an echinus, in July, on the upper surface of the leaf of 

 the honeysuckle. In fourteen days they are hatched, when 

 the young caterpillars commence life on their own account. 

 The leaf falls in autumn, and each young creature, 

 without any instruction from its mother, who died before 

 it was born, is taught by instinct what to do; for, when 

 it has eaten the leaf half-way, it begins to prepare for 

 the future. Knowing that the leaf will drop, it spins a 

 silken thread by which it is securely attached to the 

 stem. It then folds up the remainder of the leaf, enclos- 



