338 THE MICROSCOPE 



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 td 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 manner, and their resemblances 

 and differences noted. The granules of potato-starch are as 

 distinctly marked as any. 



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

 every specimen prepared for microscopical examination. In 

 order to study these, any cotton, woollen, or linen fabric 

 or garment, may be scraped, and the scrapings placed on 

 a piece of glass moistened with water, covered with the thin 

 glass plate or cover as before, and examined with the same 

 magnifying power, namely, from one hundred to six hun- 

 dred 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 procured from the epidermis or outer 

 membrane of the leaves or stems of plants, by cutting 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 different animals, the fibres of paper, the 

 most common animalcules in water, the dust of shelves, and 

 generally the structures found in all vegetable and animal sub- 

 is. The examination with solution of iodine ? Advice respecting other articles? 



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



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



