18 THE MICROSCOPIST. 



found at Mneveh, and by the numerous gems and tablets 

 so finely engraved as to need a magnifying glass to detect 

 their details. 



In commerce, the microscope has been used to detect 

 adulterations in articles of food, drugs, and manufactures. 

 In a single year $60,000 worth of adulterated drugs was 

 condemned by the Kew York inspector, and, so long as 

 selfishness is an attribute of degraded humanity, so long 

 will the microscope be needed in this department. 



In agriculture and horticulture microscopy affords valu- 

 able assistance. It has shown us that mildew and rust in 

 wheat and other food-grains, the " potato disease," and 

 the " vine disease," are dependent on the growth of minute 

 parasitic fungi. It has also revealed many of the minute 

 insects which prey upon our grain-bearing plants and fruit 

 trees. The damage wrought by these insects in the United 

 States alone has been estimated by competent observers 

 as not less than three hundred millions of dollars in each 

 year. The muscardine, which destroys such large num- 

 bers of silk-worms in France and other places, is caused 

 by a microscopic fungus, the Botrytis bassiana. 



The mineralogist determines the character of minute 

 specimens or of thin sections of rock, and the geologist 

 finds the nature of many fossil remains by their magnified 

 image in the microscope. 



The chemist recognizes with this instrument excessively 

 minute quantities and reactions which would otherwise- 

 escape observation. Dr. Wormley shows that micro- 

 chemical analysis detects the reaction of the 10,000th to 

 the 100,000th part of a grain of hydrocyanic acid, mer- 

 cury, or arsenic, and very minute quantities of the vege- 

 table alkaloids may be known by a magnified view of their 

 sublimates. The micro-spectroscope promises still more 

 wonderful powers of analysis by the investigation of the 

 absorption bands in the spectra of different substances. 



In biology the wonderful powers of the microscope find 



