CUTTING BONE AND TEETH SECTIONS. 2OI 



when arrived at this stage, finished off first on the pumice 

 slab with water, and finally on the Water-of-Ayr stone. 



The study of coal sections gives us much insight into the 

 formation of that peculiar substance. Fossil fungi have 

 been found in coal, and described by Mr. Worthington 

 Smith as belonging to the genus Peronospora, and the 

 plants have therefore been called Peronosporites. They are 

 shown in Fig. 184. 



Bone and teeth are generally cut with a saw, and after- 

 wards rubbed down with a hone and water. Dr. Beale 



FIG. 184. 



objects to this method, as filling up the lacunae and 

 canaliculi with debris, and advises cutting a thin section 

 with a sharp knife, afterwards staining with carmine. Mr. 

 George Hoggan described a machine for cutting sections of 

 hard substances to the members of the Quekett Club, in 

 which he stated that each section was cut in two or three 

 minutes, which, after brushing away the sawdust, was ready 

 for mounting in balsam. 



A few months since, Dr. Matthews described a machine 

 for a similar purpose at a meeting of the Royal Micro- 

 scopical Society, an illustration of which is shown in 



