110 



should be avoided. From time to time the liquid which 

 is lost by evaporation is replaced by a fresh addition of the 

 carbolic-fuehsine, and under no condition should the dye 

 be allowed to dry down on the cover-glass. Best results 

 in heating are obtained with the flame turned low, so that 

 it is not over two inches high. After heating the speci- 

 men in this manner for two or three minutes the stain is 

 thoroughly washed off with water and the cover-glass 

 examined wiih the No. 7 objective. Colorless spores 

 should no longer be visible, but everything should be 

 stained a deep red. If the spores are not colored the heat- 

 ing with carbolic-fuchsine is repeated until they become 

 stained. The cover-glass may be floated on hot carbolic- 

 fuchsine in an Esmarch dish for ^ to 1 hour. 



The cover glass having deeply stained spores is then 

 moved about in dilute alcohol, and, from time to time, 

 washed with water and examined with the No. 7 objective. 

 As soon as the bacilli are decolored the washing in alco- 

 hol is discontinued. The specimen then shows bright red 

 spores within cells that are almost or wholly colorless. 

 The cover-glass is then stained for a short time with 

 methylene blue, washed with water and examined. The 

 spores should be stained deep red while the bacillus itself 

 should be light* blue. 



Spores may be readily simple stained by passing the 

 cover-glass, after it has been fixed, 8 to 10 times through 

 the flame. Then the specimen is heated for 1 to 2 min- 

 utes with carbolic-fuchsine. 



The carbolic-fuchsine solution known also as ZiehTs 

 solution, is prepared by adding 1 g. of fuchsine and 13 c. c. 

 of absolute alcohol to 100 c. c. of 5% carbolic acid. The 

 solution is heated on the water-bath until everything 

 dissolves and the solution has a clear bright red color. 



