STAINING OF FLAGELLA. 2I 
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 
Ae stain; Moore’s modifica- 
tion of Loeffler’s stain ; 
‘. Van Ermengem’s nitrate 
\ X IN of silver method ; Léwit’s 
copper-sulphate fuchsin 
Fig. 15.* mordant, followed by Ehr- 
lich’s anilin-water gentian violet. (For other methods consult “Formule” 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 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 stain 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: (1) 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 very resistant to steam heat 
or to hot water, z ¢., 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 
*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. 
Fic. 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. About two-fifths natural size. 
