. Diseases of bees. Bees. Sept. 1,1932 Commercial Honey and Spread oj American Foulbrood 269 c c flasks bv adding 4 c c of a dilution to 36 c c of sterUe water. The series of dilutions containing gradually decreasing numbers of spores per cubic centimeter to be used in inoculating the culture medium were then prepared as indicated in Table 4. Sterile burettes were used in adding the proper proportions of spore suspension or spore- suspension dilutions to the proper quantities of sterile water in sterile test tubes, in order to make up the desired series of dilutions contain- ing approximately
. Diseases of bees. Bees. Sept. 1,1932 Commercial Honey and Spread oj American Foulbrood 269 c c flasks bv adding 4 c c of a dilution to 36 c c of sterUe water. The series of dilutions containing gradually decreasing numbers of spores per cubic centimeter to be used in inoculating the culture medium were then prepared as indicated in Table 4. Sterile burettes were used in adding the proper proportions of spore suspension or spore- suspension dilutions to the proper quantities of sterile water in sterile test tubes, in order to make up the desired series of dilutions contain- ing approximately known numbers of spores. Inoculation op Culture Medium Swann has observed that in old cultures of anthrax a considerable percentage of spores are dead and therefore never germinate. Be- cause of the possibility that some of the spores in the stock suspensions of Bacillus larvae might not be viable, an effort was made to determine the approximate proportions of viable and dead spores in the stock suspen- sions. Since the determination of viable spores of B. larvae by means of plate cultures is difficult because of the opaqueness of the special culture medium that is required, an attempt was made to determine the percent- age of viable spores by the differential stain- ing method of Burke (4) as modified by Koser and MUls (IS). The procedure is as follows: A small quantity of the spore suspension is spread in a thin film on a slide and allowed to dry without heating. The slide, after immersion in a solution of carbol fuchsin at room temperature for two minutes, is washed in water and decolorized with absolute ace- tone for a few seconds, washed again, and immersed in Loefiler's alkaline methylene blue for two minutes, washed, dried, and examined. Very few solid-staining forms were observed in any of the suspensions ex- ^'<'™t^tinrotKii sXensS ^'' amined, possibly one or two spores in several fields. It was therefore assumed that the number of nonviable spores could be consid
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