24 I. STRUCTURE OF STARCH. 



a " starch skeleton," which may show the size and form of the 

 original grain, and even stratifications, but in which its chemical 

 constitution has been very greatly altered. 



With this we close our first Lesson. Before we put the 

 microscope on one side we carefully clean, in the manner before 

 described, the objectives and eye-glasses, together with any 

 other pieces of apparatus that we have used. We withdraw the 

 microseope-tube from its sheath (if it has a sliding-tube) in order 

 to rub it, and also the interior of the sheath, with a rough towel. 

 Instead of again replacing the microscope in its cabinet, we 

 prefer to place it under a glass bell- jar, which latter, in order to 

 protect the instrument as much as possible from dust, can have 

 its lower edge standing on felt or surrounded with a ring of 

 chenille, such as is commonly used with glass shades for covering 

 ornaments. It may be necessary from time to time slightly to 

 oil the screw and bearings of the microscope ; if so the best 

 jewellers' oil should preferably be used, now and then cleaning 

 the oiled parts with benzine. 



