432 THE MICROSCOPE. 



more strikingly manifest. Nearly all the most useful and important 

 articles of the Materia Medica are grossly and systematically adulte- 

 rated, often to an enormous extent; so that it is impossible to estimate 

 the strength of the different remedies administered, or the extent 

 and character of the effects produced. The greatest confusion and un- 

 certainty are thus introduced into the practice of medicine, and, no 

 doubt, many valuable lives are annually sacrificed. For confirmation 

 of this statement, see Keports of the Analytical Sanitary Commission, 

 in the Lancet, 1853 and 1854, on the Adulteration of Jalap, Scammony, 

 Opium, &c. 



We nevertheless believe that the growing intelligence and inquir- 

 ing spirit of the masses, with the greatly increased facilities of detec- 

 tion so ably pointed out by Dr. Hassall, and afforded by modern 

 science, will tend not merely to check the evil for the time being, but 

 ultimately suppress 'such dangerous practices. A remedy is in the 

 hands of the people ; let them only interest themselves in that which 

 so nearly concerns their health nay, lives. Every man should be 

 able to ascertain the quality and general purity of the substances that 

 form his daily food : this he may do by acquiring a knowledge of the 

 microscope ; and by taking such a book as Dr. Hassalls for his guide, 

 he will soon learn where to look for adulterations, what to look for, and 

 how to find them out easily for himself. 



All plants are provided with hairs ; and a few, like insects, with 

 weapons of a defensive character. Those in the Urtica dioica, com- 

 monly called the Stinging-nettle, are elongated hairs, developed from the 

 cuticle, usually of a conical figure, and containing an irritating fluid ; 

 in some of them a circulation is visible : when examined under the 

 microscope, with a power of 100 diameters, they present the appear- 

 ance seen at No. 2, Plate XVI. At No. 3, same plate, we have repre- 

 sented a few of the interesting ciliated spores from Confervce. 



The next of the cell-contents falling under our notice is that to 

 which leaves owe their green colour, and is known as Chlorophyl. It 

 is of a resinous nature, containing nitrogen formed under the action 

 of light, and not otherwise. In the autumn its colour changes to red 

 or yellow. It is soluble in spirits of wine or ether, but not in water ; 

 and is usually contained in cells lying below the surface. The astonish- 

 ing circulation of the fluid-contents of vegetable cells may be examined 

 at the same time as the Chlorophyl granules, by selecting for the pur- 

 pose the transparent water-plants Chara, Nitella, Anacharis, and Val- 

 lisneria, or the hairs of Groundsel and Tradescantia. The circulation 

 of the sap in plants growing in water is now termed by botanists Cydosis. 



