SIMPLE DISSECTING MICROSCOPES. 



163 



one insect until a good knowledge of its anatomy has been 

 gained, and by no means take the trouble to prepare and 

 mount any imperfect specimens. Persevere until the dis- 

 sections are perfect, and then spare no trouble or pains in 

 preserving them for future reference. 



Dissections may be carried on with but few instruments ; 

 a few small-sized troughs, 

 knives, scissors, needles, and 

 camel-hair pencils are nearly 

 all the requisites. The dis- 

 secting microscope must be 

 left to the taste of the ope- 

 rator, who will find many 

 forms to select from. 



Fig. 148 shows Collins' 

 cheap dissecting microscope, IG * * 4 



of which a large number are in use in Professor Henslow's 

 botanical classes ; while the next figure (149) is an illustra- 



FIG. 149. 



tion of Houston's botanical dissecting microscope, which 

 may suit botanists who wish for nothing more than a steady 

 stand for a pocket magnifier. 



This ingenious little instrument is intended to provide 

 working botanical students with a convenient and service- 

 able dissecting microscope at a moderate cost. The box 

 measures, when closed, 9 inches long, 4 inches wide, and 



M 2 



