14 STUDIES IN ANIMAL LIFE. 



of animals which grow on and in men and animals ; 

 so that science can now boast of a parasitic Flora 

 and Fauna. In the fluids and tissues, in the eye, 

 in the liver, in the stomach, in the brain, in the 

 muscles, parasites are found, and these parasites 

 have often their parasites living in them ! 



We have thus taken a bird's-eye view of the field 

 in which we may labor. It is truly inexhaustible. 

 We may begin where we please, we shall never 

 come to an end ; our curiosity will never slacken. 



" And whosoe'er in youth 

 Has through ambition of his soul given way 

 To such desires, and grasp'd at such delights, 

 Shall feel congenial stirrings late and long." 



As a beginning, get a microscope. If you can not 

 borrow, boldly buy one. Few purchases will yield 

 you so much pleasure ; and, while you are about it, 

 do, if possible, get a good one. Spend as little 

 money as you can on accessory apparatus and ex- 

 pensive fittings, but get a good stand and good 

 glasses. Having got your instrument, bear in mind 

 these two important trifles work by daylight, sel- 

 dom or never by lamplight ; and keep the unoccu- 

 pied eye open. With these precautions you may 

 work daily for hours without serious fatigue to the 

 eye. 



Now where shall we begin? Any where will 

 do. This dead frog, for example, that has already 

 been made the subject of experiments, and is now 

 awaiting the removal of its spinal cord, will serve 



