THE MICROSCOPE. 243 



12. Preliminary Studies. In order to prepare the 

 way for the study of any department of science with the 

 aid of the microscope for the microscope is but an eye, and 

 can be turned in almost any direction for purposes of in- 

 vestigation it is necessary to become acquainted with the 

 many objects which are liable to complicate the examina- 

 tion of particular structures. Botli air and water are full 

 of floating bodies, and the most common of these should 

 first occupy the attention. In the city, particles of starch 

 are always floating in the air. Take a very minute portion 

 of wheat flour, place it in the middle of a clean glass " slide," 

 drop upon it a drop of pure water, cover it with a plate 

 of thin glass, and examine it with a power of from one 

 hundred to six hundred diameters. It will be found to be 

 composed of minute grains or granules, the largest of which 

 are made up of coats or layers, like an onion, arranged 

 around a central spot called the hilum. 



13. Make another preparation in the same manner, and, 

 after adding the water and before covering with the thin 

 glass cover, add a small drop of a solution of iodine. 

 Now, upon examining the specimen, every grain will be 

 seen to be of a beautiful deep blue color. After thus 

 studying wheat starch, the starch of Indian corn, of arrow- 

 root, and of various grains should be examined in like man- 

 ner, and their resemblances and differences noted. The 

 granules of potato-starch are as distinctly marked as any. 

 (See Fig. 15, page 61.) 



14. Fibres of cotton, lint, and wool are liable to be 

 found in every specimen prepared for microscopical exami- 

 nation. In order to study these, any cotton, woollen, or 

 linen fabric, or garment, may be scraped, and the scrap- 

 ings placed on a piece of glass moistened with water, cov- 

 ered with the thin glass plate or cover as before, and exam- 



1 2. Bodies, in air and water ? The examination of starch ? 



13. The examination with solution of iodine? Advice respecting other arti- 

 cles ? 



14. Directions for examining cotton and- other fibres ? Vegetable hairs ? 



