OF MICHOSCOPIC OBJECTS. 5 



IST DIVISION. 



Under our first head may be ranged the following : 

 Acetic acid. 



Liquor potassae and sodas. 

 Concentrated sulphuric and hydrochloric acids (the latter 



saturated with chlorine). 

 Tannin. 



Lime and baryta water. 

 Oxalic acid. 



Nitric acid with chlorate of potash. 

 Ammonia. 

 Alcohol. 

 Iodine. 

 Glycerine (?) 

 Phosphoric acid (tribasic). 



Acetic acid more or less dilute, e.g. one part to five of 

 water, after a sufficiently prolonged immersion, renders 

 transparent the following tissues, without in general des- 

 troying their connective tissue: some muscles (of the frog 

 (Kolliker),) cell-walls generally (not the nucleus), epithelial 

 structures, white fibrous tissue. Dr. Beale says that yellow 

 fibrous tissue is unaltered by it. Many kinds of formed 

 material, sections of preparations which have been hardened 

 by alcohol. Dr. Beale also says that it dissolves granular 

 matter composed of albuminous material, and that many 

 tissues are quite insoluble in it, though they are not ren- 

 dered opaque by it. Acetic acid renders some tissues trans- 

 parent by dissolving out the phosphate or carbonate of lime, 

 which they may contain, but it has no similar solvent power 

 over oxalate of lime. Parts which are unaffected by this 

 acid are then made more conspicuous. 



Liquor potassae and liquor sodas act in much the same 

 way, according to the degree of their dilution, but on different 

 structures. Albuminous tissues, epithelium, &c., are either 

 dissolved by them or rendered so transparent as not to 

 obstruct the view of the subjacent structures. 



