no 



THE ART OF MAKING MICROSCOPE SLIDES 



Cutting 



is tliat it may he desiralile to interrujit 

 ribbon cutting for some time and to con- 

 tinue later. In this case the worker should 

 furnish himself with a Httle glass-topped 

 frame which is laid over the jiaper to pre- 

 vent the sections from being blown about. 

 As the inexperienced worker will soon 

 find out, the least draft of air, particularly 

 the explosive draft occasioned by some 



not he cut up until a samjile has been 

 flattened on a slide in order to determine 

 the degree of expansion. Though the sec- 

 tions shown in the illustration are being 

 mounted on an ordinary 3" X 1" slide, 

 it would be moi'e practical (for a ribbon 

 as wide as this) to use a 3" X IH^' or 

 even a 3" X 2" sUde. The sections should 

 never occupy the whole area of the slide. 



Fig. 67. Cutting tlie ribbon in lengths. 



fool opening the door, is quite sufficient 

 to scatter the ribbons all over the room. 

 These operations of carrying the ribbon 

 out with the left hand, transferring the 

 Inrush to the right hand, and cutting the 

 ribbon off, are continued until the whole 

 of the required portion of the block has 

 been cut and lies on the paper. 



The ribbon must then be divided into 

 suitable lengths for mounting on a slide 

 (Fig. 67). Though in theory a section 

 should be of the same size as the block 

 from which it came, this practically never 

 occurs in practice and it is usually safe to 

 allow at least ten and sometimes twenty 

 per cent for expansion when the sections 

 are finally flattened. The ribbon should 



but at least j-i of an inch should be left 

 at one end for subsequent labeUng. When 

 the decision has been made as to how 

 many sections shall be left in each seg- 

 ment of ribbon, the first row of ribbons 

 is then cut into the required lengths (Fig. 

 67). Then the worker must decide what 

 shall be used to make them adhere to the 

 shde. It is conventional to use the albu- 

 men adhesive of Mayer 1880 (Chapter 28, 

 V 21.1), and to apply a thin smear of this 

 on a clean sUde with the tip of the httle 

 finger. The author prefers to dilute the 

 selected adhesive two or three hundred- 

 fold with water, and to use this dilute ad- 

 hesive in the next operation of flattening 

 the sections. 



