AND HOW TO USE IT. 39 



a watery solution of eosin, etc. In young bone, where ossification 

 is progressing, the cartilage matrix is blue, while the nuclei of the 

 cartilage-cells adjoining the line of bone are red ; the contents of 

 the medullary spaces also are bright red, while in the bone 

 trabecules there is a coiiibinatmi of blue and red. 



Logwood and Eosin :— 



(i.) Make a strong infusion of logwood chips in tepid water, 

 add 3 or 4 drops of this to a watch-glass full of distilled water, 

 and place the sections in it for about 15 minutes. 



(ii.) Wash the sections thoroughly in ordinary water, and 

 transfer to acidulated water for a few seconds (30 minims of acetic 

 acid to I pint of distiUed water), to get rid of superfluous 

 staining ; re-wash thoroughly in ordinary water. 



(iii.) Place in rectified spirit * for an hour. 



(iv.) Transfer to an alcoholic solution of eosin (3 grains to i 

 ounce of alcohol) for an hour, or the sections may remain in this 

 solution for any length of time, as the eosin only acts upon the 

 tissue elements to a certain extent, and no further. 



(v.) Wash quickly in rectified spirit. If the sections are 

 allowed to remain in the spirit, the eosin stain will be removed, hence 

 it is necessary merely to rinse them in spirit, and transfer them 

 quickly to oil of cloves, previous to mounting them in Canada 

 balsam or gum dammar. 



6.— Eosin and Aniline colours.— First stain in an alcoholic 

 solution of eosin, then in a i % watery solution of an aniline 

 colour (dahlia, methyl-violet, or aniline green). Care must be 

 taken not to extract the colour when dehydrating the specimen in 

 alcohol according to the usual method ; very deep staining is 

 therefore desirable. 



Eosin and Bismarck Broivji. — Put the sections in a strong 

 aqueous solution of Bismarck brown, remove after about 2 

 minutes, set in a weak acetic acid solution (4 %), then place in a 

 weak alcoholic or aqueous solution of eosin, and then again in 

 the acetic acid solution ; dehydrate with alcohol, mount in 

 dammar varnish. 



* Rectified Spirit of sp. gr. o"3SS should be used here ; where, however, 

 it cannot be easily procured, ordinary methylated spirit will do. 



