350 



THE MICROSCOPE. 



whereas by the use of the microscope the differences of 

 structure in these two substances, as in many other cases, 

 can be promptly discerned. Out of thirty-four samples of 

 coffee purchased, chicory was discovered in thirty-one ; 

 chicory itself being also adulterated with all manner of 

 compounds. There is no falling back either upon tea or 

 chocolate ; for these seem rather worse used than coffee. 

 Tea is adulterated, not only here, but still more in China ; 

 while as to chocolate, the processes employed in corrupting 

 the manufacture are described as " diabolical." " It is 



Fig. 195. 



1, Radiating cells from the outer shell of the Ivory Nut. 2, Section of a Nut, 

 showing cells with small radiating pores. 



often mixed with brick-dust to the amount of ten per 

 cent., ochre twelve per cent., and peroxide of iron twenty- 

 two per cent., and animal fats of the worst description. In 

 this country, cocoa is sold under the names of flake, rock, 

 granulated, soluble, dietetic, homoeopathic cocoa, <fcc, fig. 

 191. Such, names are evidently employed to disguise the 

 fact that they are compounded of sugar, starch, and other 

 substances. 



To return to the subject more immediately before us — 

 Some of the plants belonging to the Orchidese — Com- 

 melinece — particularly Tradescantia virginica (Spiderwort), 

 portions of the epidermis, and the jointed hairs of 

 the filament, form interesting microscopic objects. The 

 surface of the latter is marked with extremely fine longi- 

 tudinal parallel equidistant lines or striae, whose intervals 



of an inch. It 



are equal, from about Yshuu *° i 

 might therefore in some cases be used as a micrometer or 

 test object. The nucleus of the joint or cell is very dis- 

 tinct as well as regular in form ; and by gentle pressure 



