1836 Journal of Applied Microscopy 



An Improved Method for Staining Flagella. 



Up to the present time no method has been devised that will enable one to 

 stain flagella with any degree of certainty. 



The great difficulty — according to the writer's experience — has been in the 

 amount of handling necessary to secure the proper dilution of bacteria upon 

 the cover-glass. 



This can be done with very little handling by the following method : to a 

 tube containing 5 c. c. of sterile water, add enough of an lS-24 hour agar culture 

 of bacteria to produce a very faint turbidity in the upper half of the water. 



After the proper amount of bacteria have been added, the tube is placed in 

 an incubator run at the optimum temperature for the particular species under 

 consideration, and incubated for one hour. After the culture has been incubated, 

 two or three drops of the culture are placed upon a clean cover-glass and allowed 

 to dry spontaneously at the temperature of incubation. Fix by passing through 

 the flame, and stain by Pitfield's flagella stain. 



pitfield's flagella stain. 

 The Mordant : 



Tannic acid, 10 per cent, aqueous solution - - 10 c. c. 



Corrosive sublimate, saturated aqueous solution - 5 c. c. 



Alum, saturated aqueous solution - - - - 5 c. c. 



Carbol fuchsin - - - - - - - 5 c. c. 



The Stain : 



Alum, saturated aqueous solution . . - . 10 c. c. 



Gentian-violet, saturated alcoholic solution - - 2 c. c. 



Pour over the dried and fixed film as much of the mordant as it will hold. 

 Heat over the free flame until steam begins to rise ; keep at this temperature for 

 one minute. Wash in running water, dry thoroughly, and add stain. Heat, 

 dry, and mount in balsam. This method has given very satisfactory results in 

 the hands of the writer and his colleagues. Arthur I. Kendall. 



Lawrence, Mass. 



On Preparing Vertebrate Skeletons. 



A collection of the skeletons of the different familiar vertebrates is of great 

 practical value to any biological department, but their cost if purchased outright 

 or the supposed difficulty of preparation brings it to pass that although a collec- 

 tion of mounted skins has much less teaching value and costs more, it is more 

 common to see a collection of mounted animals, especially of birds, than a col- 

 lection of skeletons. The processes of skeletonizing are not as difficult as per- 

 haps they may seem, and less exacting than those of zoological technique in 

 many other departments. If they were more familiar it would often be possible 

 to save materials for osteological preparations which at present are thrown out 

 with the waste. There are frequently students in a biological department pos- 



