Staining Process. 37 



the connective tissue corpuscle in the mesentery of the 

 newt, and at the same time shows the non-striped 

 muscle tissue very well. It is also useful in bringing 

 out the delicate tissue in the tubuli seminiferi of the 

 testis and showing the developing spermatozoa there. 



In any tissue when there are elements of different 

 kinds, such as scalp or developing bone, it will be 

 found to give very good results. The logwood stain 

 must not be too deep, as it is a very opaque colour. 



CARMINE AND INDIGO- CARMINE. 



This is a very useful double stain, and is especially 

 applicable to sections made from material hardened in 

 chromic acid mixture as they do not require to be 

 passed through a solution of bicarbonate of soda, but 

 can be placed at once in the carmine solution. 



In this staining process three solutions are necessary. 



I. Carmine solution (page 24). 



II. Hydrochloric acid, 1 part ; absolute alcohol '795, 

 9 parts. 



III. Indigo carmine solution (page 25). 



STAINING PROCESS. 



Take a few drops of No. 1 in a watch glass and im- 

 merse the sections, let them remain for two or three 

 minutes and then remove them to a watch glass con- 

 taining a small quantity of No. 2. Let them remain 

 in this until they take on a bright rose colour, which 

 will be in a few seconds, then wash them in methyl- 

 ated spirit to get rid of the acid. They must be washed 

 in several changes of spirit. When the acid has been 



