186 IVAN V. SHUNK 



The addition of the drop of mordant solution B to the eight 

 drops of ferric tannate in solution A, gives a very fine precipitate 

 which is largely responsible for the success of this method. 

 Although I have been unable to prevent the precipitate from 

 clinging to the glass to a greater or less extent, I have been able 

 to demonstrate flagella with a remarkable regularity. In certain 

 species it is usual to get flagella to show on practically every 

 slide, and they are usually quite heavily stained. It is frequently 

 possible to note the presence of flagella by the use of the 16 mm. 

 objective of the microscope. 



This process has given very good results in the hands of stu- 

 dents who are doing only their third laboratory period's work 

 on staining of any kind. Most of the class are able to get flagella 

 in their first attempt, without any previous experience in flagella 

 staining at all. I have found it possible, by shortening the time 

 of allowing the mordant and stain to act, to demonstrate flagella, 

 mounted in balsam, in a little less than five minutes from the 

 time the bacteria were placed on the cover-glass. 



I have modified the process slightly to see if it were possible 

 to color the flagella differently from the cell wall. After allowing 

 the action of the chrom-acetic fixing solution, and of the mordant, 

 the preparation was stained with either Loeffler's methylene 

 blue, or the special methylene blue for four or five minutes, then 

 1 per cent safranin in 50 per cent alcohol was applied for from 

 two to four minutes, and the cover-glass preparation was washed, 

 dried, cleared with cedar oil, and mounted in balsam. This 

 modification of the process was tried mainly with Bacillus 

 vulgaris, and gave fairly good results at times. The flagella 

 appear red, the cell wall bluish, and the color of the protoplast 

 is about the same color as that of the flagella. This gives further 

 support to the contention that the flagella are not appendages 

 of the cell wall, as they were formerly supposed to be, but rather 

 continuations of the protoplast. 



SUMMARY 



This modification of Loeffler's method differs from previous 

 modifications chiefly in the use of a solution of anilin-oil in 

 alcohol (1:4) in connection with the ferric-chloride tannic acid 



