STAINING OF FLAGELLA. 



21 



Fig. 15.* 

 lich's aniliu-water gentian violet. 



Smeary dark lines and other deceptive artefacts must not be mistaken for the 

 flagella. The following methods have been tried by the writer and have given good 

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

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



modification of Loeffler's 

 stain ; Moore's modifica- 

 tion of LoefHer's stain ; 

 Van Ermengern's nitrate 

 of silver method ; Lowit's 

 copper-sulphate fuchsin 

 mordant, followed by Ehr- 

 (For other methods consult " Formulae " and 

 "Bibliography of General Literature," XII.) 



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

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

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

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

 and staiu from the covers. To furnish a steady stream the bulb has to be compressed 

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



SPORES ENDOSPORES, ARTHROSPORES. 



Do arthrospores really occur? If so, in what respect do they differ from the 

 ordinary 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 germinate except in special media? The 

 suspected existence of spores may be definitely settled 

 by seeing the problematic bodies germinate. In the 

 absence of such proof, considerable certainty may be 

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

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

 heat. If at room temperatures the glistening bodies 

 refuse to take the simple staius even on long exposure 

 and at the same time are very resistant to steam heat 

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

 nary vegetative rods, it may be assumed that they are 

 spores. If, on the contrary, they are destroyed by tem- 

 peratures only slightly 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.t 



*Fic. IS- Flagella of yellow organism plated from black spot of plum. Stained from culture 

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



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

 by sliding the bent tube through the cork. It is 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 

 single spore or bacterium for (hanging-drop studies. A-bout two-fifths natural size. 



