292 BACTERIOLOGY. 



it is not over two inches high. After heating" the specimen 

 in this manner for two or three minutes, the stain is tho- 

 roughly washed off with water and the cover- glass exam- 

 ined with 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 heating with car- 

 bolic fuchsin is repeated until they become stained. 



The cover-glass may be floated on hot carbolic fuchsin in an Es- 

 march dish for ^ to 1 hour. The carbolic fuchsin, whether in the 

 bottle or in the Esmarch dish, can be heated on the iron-plate as 

 shown in Fig. 22, p. 150. Anilin-water fuchsin can be prepared in the 

 same way as the stain which is employed in Gram's method (p 287), 

 and can be used in place of carbolic fuchsin. It will give excellent 

 results. 



The cover-glass with the deeply stained spores is then 

 placed in dilute alcohol and gently moved about. From 

 time to time, it should be washed with water and examined 

 with the No. 7 objective. As soon as the bacilli are de- 

 colored, the washing in alcohol is discontinued. The spec- 

 imen 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 or 10 times through 

 the flame. The specimen is then heated for one to two min- 

 utes with carbolic fuchsin, washed with water and exam- 

 ined. The spores are deeply stained, but the cell proper is 

 not. This excessive heating disintegrates or weakens the 

 spore-wall, and thus the dye is enabled to enter. Unfor- 

 tunately, the cell-wall proper is destroyed and hence will 

 not stain. 



The carbolic-fuchsin (ZiehVs solution), is prepared by 

 adding 1 g. of fuchsin and 13 c.c. of absolute alcohol to 100 

 c.c. of 5 per cent, carbolic acid. The liquid is heated on 



