30 CLINICAL BACTERIOLOGY AND H^MATOLOGY 



4. Carbol fuchsin is made by adding a saturated alcoholic 

 solution of fuchsin to carbolic acid lotion (i in 20) until the 

 fluid has lost its transparency, or i part of the saturated solu- 

 tion to 9 of the carbolic acid. This keeps well. 



The following* is another formula : 



Fuchsin, i gramme, or grs. xv. 

 i in 20 carbolic, 100 c.c., or giii.ss. 

 Glycerin, 50 c.c., or ixiv. 

 Or 



Fuchsin, i gramme. 

 Absolute alcohol, 10 c.c. 

 i in 20 carbolic, 100 c.c. 



5. The above stain diluted with nine or ten times its volume 

 of water. Label " Dilute Carbol Fuchsin." It is usually pre- 

 pared by diluting a little strong carbol fuchsin when required. 



6. Aniline gentian violet, which is prepared as follows : 

 First prepare aniline oil water by shaking water (preferably 



distilled) with more aniline oil than it will dissolve; a milky 

 emulsion will result, and this must be allowed to settle for a 

 short time. Then filter it through a double thickness of filter- 

 paper which has been previously moistened with water. .This 

 must be prepared fresh, and as a small amount is often re- 

 quired in a hurry, the following method is frequently most 

 useful : Put about \ inch of aniline in a test-tube, and half fill 

 the latter with distilled water. Boil for half a minute, then 

 cool under the tap. When quite cool, filter. 



To 9 parts of the solution thus obtained add i part of 

 saturated solution of gentian violet in alcohol. 



This solution keeps badly, and it is necessary .that it should 

 be freshly prepared, as very important inferences are drawn 

 from results obtained with it. The following keeps better, 

 and answers every purpose : 



Carbolic Gentian Violet (a substitute for aniline gentian 

 violet). Add i part of saturated alcoholic solution of gentian 

 violet to 9 parts of a i in 20 carbolic lotion.* 



7. Carbol thionin is made by adding i gramme of thionin 

 to 100 c.c. of a i in 40 solution of carbolic acid. 



This stain keeps fairly well, but it must always be filtered 

 immediately before use, as crystals which may have a most 



* It sometimes precipitates immediately after being made, for no apparent 

 cause. Should this not happen it usually keeps for months. 



