102 BACTERIA IN RELATION TO PLANT DISEASES. 
an oil is driven off which otherwise would be deposited as a whitish distillate on 
the inside of the test-tubes near the plugs. Hypodermic syringes may be sterilized 
by boiling in distilled water if the contaminating organism is non-sporiferous, 
or by soaking twenty-four hours in 5 per cent carbolic-acid water or lysol water and 
a subsequent soaking and boiling 
in pure water. The writer prefers 
the Meyer syringe, made by Lauten- 
schlager (fig. 86). Syringes which 
allow the culture media to ooze out 
around the piston whenever any 
strong pressure is exerted are danger- 
ous and should never be used with 
infectious material. Those which do 
not admit light or allow the experi- 
menter to see how much fluid has 
been used or whether air is present 
are unsatisfactory. In case of many 
plants, needle-pricks are more satis- 
factory than hypodermic injections 
(pl. 4 and figs. 8 and 88). Needles 
are sterilized in the open flame as 
needed. 
When conveniences are not at 
hand, as on long trips in the country, 
the kitchen-oven may be used for 
sterilizing glassware, or even an open 
flame (alcohol lamp), and agar and 
gelatin for the making of poured 
plates may be melted by placing the 
tubes in hot water in a tin cup or tea 
kettle, but, in general, the writer has 
not found the rooms of ordinary farm 
houses very well suited for research 
work. Usually they are too dusty. 
Surgeon’s gauze is very conve- 
nient for laboratory use, for coarse 
filters, wipe-cloths, etc. 
Fig. 87.* 
*Fic, 87.—Early stage in the infection of a cabbage leaf by Bacterium campestre; a, epidermal 
layer on the apical part of*the tooth of a leaf, showing one of the four stomata €X ) full of bacteria. 
For the condition immediately under X see b, which was drawn from the third section in series, the 
intermediate one including part of the guard-cells. Slide 338, Br, stained with carbol-fuchsin. 
Drawn with the Abbe camera, 3 mm, Zeiss apochromatic objective and 12 compensating ocular. 
Material collected and fixed 8 days after infection, which was accomplished by atomizing upon the 
plant water containing a pure culture of Bacterium campestre grown on slant agar. When collected 
many of the serratures had begun to show traces of the brown stain which invariably appears when 
this organism grows in cabbage. The plant was inclosed in the cage shown in fig. 95, and was ex- 
truding fluid from its water-pores when it was sprayed. X 500. 
