244 THE MICROSCOPE. 



ined with the same magnifying power, namely, from one 

 hundred to six hundred diameters. Vegetable hairs or 

 down are constantly floating in air and water. These are 

 of very various forms, are simple or grouped, and form 

 very interesting objects of study. They are readily pro- 

 cured from the epidermis or outer membrane of the leaves 

 or stems of plants, by section with a delicate knife. 



15. The tissues of plants, epidermis, ducts, and woody 

 fibres are constantly found in "microscopic preparations. 

 They may be studied in delicate sections made with 

 a sharp knife, or by tearing vegetable tissues apart with 

 needles. The down of moths, the hairs of difie rent- 

 animals, the fibres of paper, the most common animal- 

 cules in water, the dust of shelves, and generally the 

 structures found in all vegetable and animal substances 

 by which we are surrounded, should be studied as a pre- 

 liminary to any special line of microscopical investiga- 

 tion. 



16. The Study of Human Tissues. When this has 

 been done and familiarity with the use of the instrument 

 has been obtained, proceed to the study of the human 

 body, for human physiology is our subject. If the end of 

 the finger be pricked with a pin, a drop of blood may be 

 procured for examination. Place this on one of the glass 

 slides, cover it with a thin piece of glass, press down the 

 cover so as to make a thin layer, and then examine with 

 the magnifying power just mentioned. Do not add water, 

 for that will cause the blood corpuscles to disappear. If 

 the drop of blood is placed under the microscope at once 

 after being drawn from the finger, most interesting phe- 

 nomena will be observed. The red corpuscles will be seen 

 to arrange themselves in rows, like piles of coin, while the 

 blood is coagulating. The spherical, white corpuscles will 



15. Directions for examining various tissues? Down of moths, and other 

 structures ? 



1 6. Directions for examining a drop of blood ? 



