94 THE MICROSCOPE. 



together with marine-glue or sealing-wax : the size of the 

 trough should be about three inches square and one deep. 



Fig. 63. Dissecting under water. 



If thought desirable to dissect under the microscope 

 itself, the instrument must be brought over the trough, 

 and the subject adjusted to the focus of an inch or a 

 two-inch magnifier, as it is difficult to employ a higher 

 power. The simple microscope is that generally em- 

 ployed for the purpose. If the object be a portion of an 

 injected animal, it is better to pin it out on a piece of 

 cork, covered with white wax, and then immerse it in the 

 water-trough j the more delicate the structure, the sooner 

 after death should it be examined, especially animal tissues. 

 With most vegetable structures, the dissection should be 

 carried on under water. The separation of the woody and 

 vascular tissues, and the spiral vessels, is best effected by 

 maceration and tearing with fine needles. 



Valentin's Knife. For making fine sections of large 

 substances, or those soft in structure, such as the liver, 



