APPENDIX. 109 



The addition of weak hydrochloric or nitric acid is useful 

 for breaking up cellular tissue &c. 



Thin sections of most substances can be well cut by soak- 

 ing them in the india-rubber cement, which must be allowed to 

 dry ; the sections may then be made with a razor or scalpel. 



For the observation of any object the student must place 

 the same between a glass slip and a piece of thin glass. Water 

 is the fluid most generally used for rough observation ; but 

 this must be left to observation and experiment. And in the 

 mounting of objects common sense must be used; for instance, 

 an opaque-looking object is generally best mounted in balsam, 

 as it has good refractive powers, and a transparent substance 

 is generally best seen when mounted either dry or in fluids. 



Dust must be carefully kept from all preparations whilst 

 in progress. 



The author must now conclude, trusting that his readers 

 will find these rough notes useful, and that the study of some 

 of the hidden forms made by Divine art will lead him to 

 search further for the marvellous beauties of nature. 



