552 
BEES AND BEE-KEEPING. 
The material is now, probably, acid, and in it Bacil- 
lus alvei would not, on this account, grow ; a solution 
of common carbonate of soda therefore must be 
added cautiously, constantly testing with fresh scraps 
of red litmus paper,* until its red colour begins to 
become purplish. Now clarify with white of egg, in 
the cook’s way, and strain through muslin. Transfer 
the medium to the tubes through a narrow-necked 
funnel, so as not to soil the sides, filling each to 
the depth of ijin. or 2in. (^/, C, Fig. 122). Carefully 
hold the cotton plug, with the fingers, at its exposed 
end only, and re-insert immediately. So soon as 
the tubes — which must be kept upright, lest the fluid 
touches the cotton — are filled, they are stood up in 
a saucepan containing some water, and boiled for an 
hour, then allowed to cool, and similarly re-boiled 
next day. Henceforth they will keep, without change, 
until the gelatine has completely dried up, for the 
obvious reason that all germs have been destroyed. 
These tubes are valuable stock, and may be used for 
the cultivation of any germs found during our search- 
ings. A damp, cool place, in which they should be 
covered carefully from dust, is best for storing them. 
With indiarubber caps over the cotton wool, they 
may be preserved, ready for use, for years. 
Four or five inches of moderately fine platinum wire, 
called a needle, and fixed by heating into the end of 
a thin glass rod, completes our apparatus. Having 
found a bee suffering from bacilli, we pass the platinum 
wire through a gas or any other flame, heating it to 
Books of this can be bought of the chemist for about 2d. 
