24 On Staining. 



dilute the logwood stain with distilled water, as or- 

 dinary water will not give the same result, owing to 

 the different matters held in solution ; but it is better 

 to use ordinary water for washing the sections after 

 staining as it helps to fix the color. 



The solution should not be too strong, as better re- 

 sults are obtained from staining the sections slowly 

 than from doing it rapidly, and it will always result 

 in a loss of time if an attempt is made to stain a large 

 number of sections in a strong solution. 



ON STAINING SECTIONS WITH LOGWOOD THAT HAVE BEEN 

 PREPARED WITH CHROMIC ACID. 



It is necessary to remove the chromic acid from sec- 

 tions hardened in that fluid, and this is done by taking 

 some of the 5 per cent, solution of bicarbonate of soda 

 diluting it slightly, and soaking the sections in it for 

 some time, ten to twenty minutes will generally be suf- 

 ficient. 



Then remove them to plain water and wash well. 



Prepare two watch glasses of dilute logwood stain 

 and place the sections in one of them, let them remain 

 for a minute and then place them in the other ; there 

 they must stay until stained deeply enough. 



If the first watch glass be now examined, the log- 

 wood stain will be found to have become quite granular, 

 and if this precaution had not been taken it would have 

 been deposited as minute granules all over the sections. 



2. Carmine. This stain, formerly so much used, is 

 now almost given up by Histologists, as a general stain, 

 in favor of logwood which is found to differentiate the 



