62 LABORATORY BACTERIOLOGY 



EXERCISE XIX 



STAINING THE FLAGELLA ON MOTILE BACTERIA 



93. The motile bacteria are provided with a variable num- 

 ber of long, hairlike appendages or flagella. These are invisi- 

 ble in the fresh preparation, and they do not stain by the 

 ordinary methods. By special staining processes, however, their 

 presence can be detected. Several methods have been pro- 

 posed for staining these filaments, but nearly all of them are 

 based on the use of a mordant. Curiously enough the value 

 of each of these methods seems to rest largely on the skill of 

 the individual using them, as some workers succeed with one 

 method while others fail with it but obtain excellent results 

 with one of the other processes. Although the flagella are 

 known to be the organs of locomotion, they do not seem to be 

 of any special morphological value in differentiating closely 

 related species. They are, however, elements in the structure of 

 motile bacteria, and their demonstration is much to be desired. 



REFERENCES. Chapters on staining flagella in standard text- 

 books. Moore, A Review of the Methods for Staining Flagella 

 on Motile Bacteria, Am. Monthly Mic. Journal, Vol. XII (1891), 

 p. 15. Moore, The Character of Flagella, etc., Wilder Quarter- 

 Century Book, p. 339. Loeffler, Centralblatt fur Bakteriologie, 

 etc., Bd. VI (1889), S. 20 9- Ferrier, Achives de MeU Exp. et 

 d'Anat. pathologique, T. VII (1895), p. 58. Van Ermengem, 

 reviewed in Centralblatt fur Bakteriologie, etc., Bd. XV (1894), 

 No. 24. Johnston and Mack, Am. Med., Vol. VII, p. 754. 



94. Work for this exercise. Make a cover-glass preparation 

 from the growth on the agar culture of Bacillus cholera suis 

 made in Exercise XVII and stain it with carbol fuchsin. 

 Preserve this to compare with preparations stained for the 

 purpose of demonstrating the flagella. 



Clean about 10 cover glasses after the special method for 

 flagella staining ( 4). Make about 5 films on these from the 



