80 The American Naturalist. [January 



orably associated. Fortunately her work as an entomologist is not t< 

 be interrupted, and she will continue to place her knowledge at th< 

 service of agriculturists." 



The newspapers report that a large manufacturing building a 

 Springfield, Illinois, has been riddled by an insect borer, apparently i 

 11 beetle. 



MICROSCOPY. 1 



A New Method of Using Celloidin for Serial Section 

 Cutting. — The following has several features which recommend it as 

 preferable to the ordinary methods of section cutting. — It allows a 

 perfect orientation ; the entire object is visible during the process of 

 cutting; yolk-bearing eggs offer no serious difficulty; sections of large 

 area and of unusual thinness are easily secured ; crimping and curling 

 during the process of clearing are avoided and the sections may be 



The object is first stained in Mo, dehydrated, infiltrated with thin, 

 medium and thick celloidin or collodion, (Squibbs Flexible Collodion 

 rendered thick by evaporation is excellent) and finally placed in a 

 paper tray filled with the thick collodion. In a few moments a film 

 will form over the exposed surface of the collodion, when the paper 

 tray with its contents is thrown into a jar of strong chloroform, in 

 which after a few hours, the collodion becomes quite hard. Thus far 

 we have been following only the more ordinary methods. 



The tray is now taken from the chloroform and, after the paper has 

 been removed from the hardened block, the collodion with its enclosed 

 object is placed in a vial of white oil of thyme, or some other similar 

 oil. If the block of collodion is not large, in a few hours it will 

 become as clear as glass, the stained object appearing as if suspended 

 in a transparent fluid. 



For the process of orienting, the block of collodion may now be 

 taken from the oil, placed in a watch crystal and, after covering with 

 the oil of thyme, examined with a lens or, if more desirable, with a 

 compound microscope. The side of the block that is to be attached to 

 the object holder of the minotome is now selected, wiped dry of the oil 

 and immersed for a moment in ether and then smeared with thick 

 collodion. The object holder, a block of wood rather than cork, is 



'Edited by C. O. Whitman, Clark University, Worcester, Mass. 



