. Diseases of bees. Bees. entire apparatus is sterilized in the autoclave, using a temporary empty flask into which the stopper for the culture flask is placed, and all is wrapped in paper with a paper protective cap over the open end of the delivery bell. Before use, the apparatus is removed from the paper and the stopper is carefully removed from the empty flask so as to prevent contamination and is fastened firmly in the fliask containing the egg-yolk suspension. After placing the pinch cock in position, the apparatus is carefuUy inverted and hung on a ring stand. The small-bore glass tube
. Diseases of bees. Bees. entire apparatus is sterilized in the autoclave, using a temporary empty flask into which the stopper for the culture flask is placed, and all is wrapped in paper with a paper protective cap over the open end of the delivery bell. Before use, the apparatus is removed from the paper and the stopper is carefully removed from the empty flask so as to prevent contamination and is fastened firmly in the fliask containing the egg-yolk suspension. After placing the pinch cock in position, the apparatus is carefuUy inverted and hung on a ring stand. The small-bore glass tube in the flask now reaches a little above the surface of the hquid and serves for an air inlet. By means of this apparatus, sterile egg-yolk suspension can be added to tubes of sterile base medium, with little danger of external con- tamination, by inserting the tube under the protective beU. METHOD OF ISOLATION OF PURE CULTURES OF BACILLUS LARVAE Fig. 7.—American foiUbrood j. j scale. End view. (White When medium IS desired for the isolation or cultiva- (««)) tion of Bacillus larvae, tubes of the yeast-extract agar are melted in a water bath and cooled to 55° C, after which from 1 to 2 cc. of egg-yolk suspension is added for each 10 cc. of base, by means of the apparatus described above. The contents of the tubes are well mixed and then slanted. From a comb containing decaying material dead of the disease, a dried scale (figs. 7 and 8) is removed with a sterilized needle scalpel (also used for removing cappings) and dropped into the water of condensation in the culture tube to soften. It is then smeared over the surface of the agar with an inoculating needle. If ropy gluelike material is available it is more satisfactory (fig. 9). A large loopful of this is removed from the cell, from which the capping has been aseptically removed by means of an inoculating needle, and is streaked over the surface of the agar. A heavy initial inoculum gives best re- sults, as it is often di
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