104 BACTERIA IN RELATION TO PLANT DISEASES. 
When ready to make the transfers or to pour the plates, close the windows, 
wipe up the tables, and wet down the floor, window-sashes, etc., with distilled water 
or boiled water, and reduce the air-currents within the laboratory to a minimum 
(especially when transfers are to be made in the open room) by keeping the doors 
shut and restricting the movements of all persons who may be in the room. It is 
much better to do all of this work in specially constructed small rooms (plate 11) 
than under hoods (plate 12). Hoods are open only in front. They may be made of 
any convenient size. ‘The one here figured is is 32 by 39 by 20% inches, outside 
measurements. When one is far from laboratories small hoods may be extempor- 
ized out of clean paper, or cultures may be poured and transfers made inside of a 
clean pail or jar, turned down on its side. Any method, in fact, which restricts 
the movement of air past open plates and 
tubes will be found serviceable. 
The work-shelf of the room shown 
in plate 11 faces a window as wide as the 
room, and extending from the level of the 
shelf to the height of the other windows 
in the room. ‘This window faces south 
and is only 6 feet from a well-lighted win- 
dow in the outer wall of the building. The 
room also receives bright light from the 
west side. At the front end of the shelf 
are a Bunsen burner with cut-off flame, a 
box of safety matches, a box of rubber 
bands, and two tumblers—one for burned 
matches and one for platinum loops, 
needles, forceps, etc. Immediately under 
this part is a narrow drawer for pencils, 
note paper, knives, ete. At the back end 
are a few wrapped Petri dishes, a nivella- 
tion apparatus, a flask of sterile water, and 
a crate of media. Underneath this part is 
a second shelf 3 inches below the first, where Petri dishes and tubes containing solid 
media may be put out of the light as fast as inoculated. ‘The size of this room 
(inside measurement) is 4 by 4 by ro feet, and it is large enough. No provision is 
made for ventilation, because air-currents in a culture-room are very objectionable. 
The windows, walls, and floor are wiped up with distilled water before making 
transfers. Outside is a bit of the author’s private laboratory. At the right is the 
microtome and behind it on the wall are deep and shallow drawers; 69 is for bulk 
paraffin; 70 A, B,C, D, E, are cut into small compartments used for paraffin blocks. 
The very shallow drawers are for ribbons which can not be mounted the day they 
are cut; 72 has a series of shelves opening on the south side and is used to hold 
photographic printing frames. 
Fig. 89.* 
*Fic. 89.—Pine block with inch holes, convenient for holding test-tube cultures during exam- 
ination, or tubes of media which are to be inoculated. A good size is 9% by 3% by 1% inches. 
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