100 PRACTICAL HISTOLOGY. 



CHAPTER V. 



BONE. 



Preparations 1 and 2. Transverse and longi- 

 tudinal sections of hard bone. These are first 

 cut as thin as possible with a fine saw, and are 

 afterwards reduced in thickness and polished by 

 grinding. The bone selected should be thoroughly 

 macerated and bleached ; it should be absolutely 

 free from grease. Sections may be made from dif- 

 ferent bones, flat and long, but for typical specimens 

 of the compact tissue, transverse and longitudinal 

 sections of one of the long bones of the limbs the 

 ulna, for instance may be recommended, and a 

 vertical section of one of the flat bones of the skull, 

 such as the parietal, should also be prepared. 



The first thing to be done is to get as thin a 

 piece as possible cut with a saw from any desired 

 part. For the purpose a fret-saw may be used, 

 unless a circular saw is available, when this, if fine 

 enough, may be employed with advantage. The 

 piece so obtained is ground down on a hone wetted 

 with water. The hone must have been previously 

 freed from all traces of greasy matter by washing 

 with soap and water with a little soda. The piece 

 of bone is pressed down and rubbed to and fro on 

 the hone simply by the finger, being ground first 

 on one side and then on the other. The feel will 

 be almost sufficient to tell when it is thin enough, 

 and this may be confirmed by placing it on a slide 

 without covering it and examining with a low 

 power. Numerous scratches will doubtless be visi- 

 ble on its surface, produced by the grain or' the stone, 

 however fine this may be ; but unless very obvious, 



