184 THE MICROSCOPE AND HOW TO USE IT. 



tion in the early embryo. A foetus, prepared by being soaked for 

 a few days in this fluid, and preserved in weak spirit, forms a very 

 beautiful preparation. Useful also for soft granular organs, and of 

 special service for the liver (Beale). 



CoUodium is used for recognising the axis cylinder of nerve 

 fibres. 



Sulphuric Acid is useful in investigating horny structures (the 

 cornified epitheHum, the nails and hair), and for isolating the cells 

 of these tissues. Alone, or combined with iodine, it forms a good 

 re-agent for cholestrin, and in combination is useful for cellulose 

 and amyloid substances. Sugar and sulphuric acid redden many 

 organic substances, such as albuminous and amyloid bodies, oleic 

 acid, etc. 



Nitric Acid, mixed with chlorate of potash, destroys connec- 

 tive tissue in a short time, and is therefore a good medium for 

 isolating muscular fibres (Kiihne). Strong acid is used for isolat- 

 ing connective tissue corpuscles, bone corpuscles and their pro- 

 cesses, and also for dentinal canals. 



Hydrochloric or Muriatic Acid dissolves the intercellular sub- 

 stance of connective tissue organs, and for isolating the connective 

 tissue corpuscles and their radiating tubular systems, as in the 

 cornea, teeth, and bones. It also dissolves the intercellular sub- 

 stance of the muscles (Aeby) and of the urinary tubes (Henle). 



Pyroligneous Acid (or acidum pyrolignosum rectificatum) is 

 used for rendering connective tissue structures transparent, and, 

 with a certain pre-dilection, is used also for pathological tissues, 

 for recognition of corneal cells and contents, course of nerves in 

 sub-mucous connective tissue, structures imbedded in connective 

 tissue, as pathological new formations, glandular elements, and for 

 extracting the bone earths from calcified cartilage and from normal 

 and pathological bone-tissues. 



Acetic Acid renders muscles transparent, so that the nerve 

 terminations may be discerned, and vinegar is used to boil such 

 animal tissues as are to be dried. 



