STAINING OF FLAGELLA. 



21 



Smear}' dark lines and other deceptive artefacts must not be mistaken for the 

 flagella. The following methods have been tried by the writer and ha\'e given good 

 results, but none can be depended upon always, and much time and patience are 

 sometimes required to get good preparations of a refractor)' organism : Fischer's 



modification of Loeffler's 

 stain ; Moore's modifica- 

 tion of Loeffier's stain ; 

 Van Ermengeni's nitrate 

 of silver method ; Lowit's 

 copper-sulphate fuchsin 

 F'g- '5-' mordant, followed by Elir- 



lich's anilin-water gentian violet. (For other methods consult " Formuke " and 

 "Bibliography of General Literature," XII.) 



In connection with flagella-staining a white porcelain tray, such as photogra- 

 phers use, will be found very convenient for washing, and also the double l^low-bulb 

 shown in fig. 17. This should be attached to a wash-bottle, such as tliat shown in 

 fig. 16. This will deliver a small stream, very good for washing excess of mordant 

 and stain from the covers. To furnish a steadv stream the bidb has to be compressed 

 onlv about once a minute. The flask used for this purpose should hold a liter. 



SrORES — ENDOSPORKS, arthrospores. 



Do arthrospores really occur? If so, in what respect do they difl^er from the 

 ordinar}' vegetative rods? Test spores for resistance to high temperatures in the 



water bath and to steam heat; study germination in 

 hanging drops. Do the spores require a period of rest 

 or refuse to genninate except in special media? The 

 suspected existence of spores may be definitely settled 

 by seeing the problematic bodies genninate. In the 

 absence of such proof, considerable certaint}' may be 

 reached by a combination of two methods: (i) the use 

 of watery basic anilin stains, and (2) the use of moist 

 heat. If at room temperatures the glistening bodies 

 refuse to take the simple stains even on long exposure 

 and at the same time are ver}- resistant to steam heat 

 or to hot water, /. e., much more so than the ordi- 

 nary vegetative rods, it may be assmned that the\- are 

 spores. If, on the contran', they are destroyed b^' tem- 

 peratures only slightl)' above the recorded thermal death- 

 point of the vegetative rods, it must not be assumed 

 that they are spores, no matter how they behave toward 



Fig. 16.- 



*Fic. 15. — Flagella of yellow organism plated from black spot of plum. Stained from culture 

 grown in 10 cc. distilled water containing a few drops of Uschinsky's solution. X 1,000. 



fPiG. 16. — Beyerinck's drop-bottle. The size and number of drops in a given time are regulated 

 by sliding tlie bent tube through the cork. It lis very convenient to have this flask on the microscope 

 table. By a minim infection of the fluid it may also be arranged so that each drop shall deliver a 

 sincrle spore or bacterium for hanging-drop studies. About two-fifths natural size. 



