BY DR. KLEIN. 107 



the color is less intense, the different tissues are rendered dis- 

 tinct by the different degrees to which they are stained. I use 

 the carmine solution for this purpose as follows: The sections, 

 having been allowed to remain for twenty or twenty-four hours 

 in a liquid consisting of one part of carmine solution and nine 

 to twelve parts of distilled water, are washed for a short time 

 in distilled water, and transferred either to glycerin (if it is in- 

 tended to mount them in this medium), or to" alcohol (if they 

 are to be mounted in Dammar). If the sections have not been 

 previously in alcohol, it promotes the staining to put them for 

 a few minutes into that liquid. If it is intended to preserve 

 the sections in gtycerin, it is desirable to add a few drops of it 

 to the staining liquid. The well-known liquid used by Beale 

 for staining fresh tissues may be also employed for staining 

 sections; but, in preparing it for this purpose, the alcohol may 

 be omitted. The composition of Beale's liquid is as follows: 



Beale's Solution. Ten grains of carmine are heated in 

 half a drachm of liquor ammonia;. As soon as the liquid is 

 cold, two ounces of distilled water, two ounces of pure glycerin, 

 and half an ounce of alcohol are added. The solution is then 

 either filtered or decanted from the undissolved carmine. This 

 liquid requires no dilution. A small quantity must be warmed 

 in a watch-glass to get rid of the ammonia, and it is then ready 

 for use. We shall find that, in the preparation of the mucous 

 membrane of the stomach, it is of special value. 



Anilin. Anilin is used in aqueous and alcoholic solution ; 

 the former being most useful. It is obtained by treating anilin 

 blue with sulphuric acid. Two Centigrammes of the soluble 

 product are dissolved in twent3'-U' r e centimetres of distilled 

 water, and twenty to twenty-five drops of alcohol. This solu- 

 tion colors sections which have been in alcohol veiy rapidly. 



Picric Acid is used in very dilute solution for the purpose 

 of staining sections yellow. Sections may be first stained in 

 picric acid, then in carmine, in which case the muscles are col- 

 ored yellow. Whatever the staining liquid employed, the sec- 

 tions must be transferred, as soon as they are sufficiently col- 

 ored, to distilled water with or without the addition of a trace 

 of acid. 



Methods of Mounting Sections. Sections may be cov- 

 ered either in glycerin, in mixtures of gelatin and glycerin, of 

 glycerin and acetic acid, of glycerin acetic acid and alcohol, in 

 Canada balsam, or in Dammar varnish. If glycerin is to be 

 used, the sections should, if they have been in alcohol, be pre- 

 viously placed in water. Glycerin alone, answers best for sec- 

 tions of tissues treated with gold or silver. Sections of organs 

 treated with osmic acid must be placed in acetate of potash. 

 Very thin unstained sections of glandular organs and of con- 



