86 A MANUAL OF BACTERIOLOGY 



kept should be painted externally with black oil 

 paint. 



To decalcify small bones or teeth, they are placed 

 in Ebrier's or Kleinberg's solution. Ebner's solution 

 contains five grammes of sodium chloride (salt), 

 5 cc. of hydrochloric acid, 20 cc. of distilled water 

 and 100 cc. of alcohol. Kleinberg's solution is 

 made as follows: 100 cc. of a saturated aqueous 

 solution of picric acid are added to 2 cc. of strong 

 sulphuric acid. The mixture is filtered and 300 cc. 

 of distilled water are added. In either solution the 

 materials (to be decalcified) remain until sufficiently 

 softened ; they are then allowed to soak in water, and 

 finally passed through weak spirit to absolute alcohol. 



For cutting sections either by hand or by the 

 microtome, it is necessary (as a rule) to imbed the 

 material in one of the imbedding mixtures. If the 

 material to be cut has been preserved in alcohol, it 

 is better first soaked in water for about ten hours to 

 remove the spirit, and then placed in mucilage T for 

 about five hours. For cutting with the non-freezing 

 microtomes, the material is imbedded in celloidin 

 or paraffin, mounted on cork. 2 To imbed in celloidin 

 the hardened material is first placed in a mixture of 

 alcohol and ether for thirty or forty minutes ; then 

 transferred to a solution of celloidin (dissolved in 

 equal parts of alcohol and ether) from two to twenty 

 hours. 3 A cork placed in the clamp of the micro- 



1 Mucilage is prepared by making a solution of gum Acacia. 



2 If the material is firm enough it is sometimes mounted on 

 cork without being imbedded. 



3 The length of time depends on the nature of the material. 

 It is longer for spongy structures like the lungs. 



