Characteristics of a Good… Morning

It makes tissues transparent.

It should not dissolve out aniline dyes.

It must produce minimum shrinkage of tissue.

It must be isotonic, causing minimal physical and chemical alteration of the cells and their constituents. This is not, however, a strict rule since there are some hypotonic solutions (i.e. glacial acetic acid) producing tissue swelling, which are being used in conjunction with hypertonic solutions (e.g. picric acid) causing shrinkage of cells, to produce a compound which would give an optimal effect on the tissue structure.

It should not be toxic to the body.

It should not produce excessive shrinkage, hardening or damage of tissue.

It must permit rapid and even penetration of tissues.

It should be able to dehydrate even fatty tissues.

It should be miscible with, and easily removed by melted paraffin wax and/or by mounting medium to facilitate impregnation and mounting of sections.

It must be stable.

It should not be a fire hazard.

It must kill the cell quickly thereby producing a minimum distortion of cell constituents.

It should not harden tissues excessively.

It should not evaporate quickly in a water bath.

It should not evaporate very fast.

It must be cheap.

It should dehydrate rapidly without producing considerable shrinkage or distortion of tissues.

It must inhibit bacterial decomposition and autolysis.

It must make cellular components insoluble to hypotonic solutions and render them insensitive to subsequent processing.

It should not remove stains.

It must be safe to handle.

It should be miscible with alcohol to promote rapid removal of the dehydrating agent from the tissue.

It must permit the subsequent application of many staining procedures to facilitate easier and more profitable examination.

It must harden tissues thereby making the cutting of sections easier.