Overview

Purchase of this book includes free trial access to www.million-books.com where you can read more than a million books for free. This is an OCR edition with typos. Excerpt from book: Ill COMMON MICRO-CHEMICAL REACTIONS. A Few further practical exercises will now be given, involving the use of common methods and reagents, and leading to a fuller knowledge of the appearance and reactions of the parts of the cell, and of some of the bodies commonly contained in it. I. Cell-walls. A. Cellulose -Walls. Take some ordinary unbleached cotton wool, which consists of unicellular hairs from the surface of the seed of the cotton plant (Gossypiuni). Moisten first with alcohol, and then soak in water. a. Mount a small quantity in water, and examine first with a low, and then with a high power: observe? 1. The long, filamentous, unicellular hairs, which compose the cotton wool, coiled irregularly together. 2. The rather thick, highly-refractive and colourless cell- wall. 3. The remains of granular protoplasm, which may still be seen within. b. Soak a small quantity of the cotton for a few minutes in iodine solution in a watch-glass, mount in iodine solution, and note the cell-walls stained slightly yellow. c. Mount a small quantity of the cotton which has been thoroughly soaked with iodine, in a single small drop of concentrate sulphuric acid diluted with an equal volume of water: the greatest care is to be observed in the use of this reagent, so that it shall not gain access to the stage, or the objective; only a very small quantity is to be used, and the slide should be -washed in water directly the observation has been made. A low power will suffice to show that? 1. The cell-walls swell greatly, and in an irregular form, and ultimately lose their sharp contour. 2. They assume a blue colour. This colouring is often not uniform, and this reaction, though trustworthy as positive evidence of the presence of cellulos...

Full Product Details

9781164904724

Table of Contents

Reviews

Author Information

Tab Content 6

Customer Reviews

Recent Reviews

Countries Available