28 On Staining. 



skin it is very useful as a ground color, and by staining 

 a number of sections of the same tissue with picro- 

 carmine and then with two other colors, a variety of 

 results will be obtained. 



In some the tissue for which picro- carmine has a 

 special affinity, such as connective tissue will be found 

 unaltered, while the surrounding tissue has taken on 

 the new colors. In others the picro- carmine has com- 

 bined with one or both, and a new color is formed. 

 Or again, it may be entirely supplanted by one of the 

 other colors. 



ANILIN DYES. 



These may be divided into two classes, those soluble 

 in water and those soluble in spirit ; and this classifica- 

 tion will be found very useful for experiments in double 

 staining. 



There are an immense number of anilin dyes now 

 manufactured, but a great many of these will be 

 found precisely similar in their colour and action, 

 although bearing different names, while others are at 

 the most only different shades of the same colour. 

 The foregoing list gives a selection of the most useful 

 of these dyes, and those marked with an asterisk will 

 be found to give the best results. Many of the others 

 would, however, be valuable stains if any means could 

 be discovered for fixing them so that they could be 

 passed through spirit without becoming obliterated. 



8. Soluble Anilin Blue or China Blue. This is a use- 

 ful stain for some tissues, such as stomach and spinal 

 cord. It is made very simply by taking some of the 



