30 



THE STRUCTURE OF 



they may be viewed by transmitted light, very 

 thin sections of them should be made. This may 

 be effected by means of a very sharp scalpel, or a 

 razor.. When objects are too small to be held 

 in the hand to be cut, they 

 may be placed between two 

 pieces of cork, and a section of 

 them made at the same time 

 that the cork is cut through. 



Sometimes it is found desir- 

 able to unravel an object under 

 the Microscope. If this is the 

 case, only a low power should 

 be used, and the object may be 

 placed on a glass slide, without 

 any glass over, and two needles 

 with small wooden * handles 

 employed, ordinary sewing 

 needles, with their eyes stuck 

 in the handle of a hair pencil, 

 will answer very well. (Fig. 14.) 

 Even when dissection is not 

 to be carried on under the 

 Microscope, a pair of needles 

 of this sort, for tearing minute 

 structures in pieces, will be 

 found very useful. 

 *& 14< When opaque objects are 



Dissecting Needles. to ^ e examined, the light from 

 the mirror may be shut off, and the aid of the 

 bull's-eye condenser called in. The object being 

 secured in the forceps attached to the stage 

 (fig. 15), or laid upon a slide, the light is allowed 

 to fall on it through the condenser. (Fig. 9.) The 

 object-glass must be focussed in the same manner 

 as for transparent objects, till the best distance is 



