| abstract |
1431458 Apparatus for microbiological testing BECTON DICKINSON & CO 9 July 1973 [16 March 1973] 32544/73 Addition to 1406847 Heading C6F The apparatus described and claimed in Specification 1406847 is improved or modified in the following respects: (1) the passage way 31, Figs. 7 and 8, is defined by a plurality of ducts dimensioned to provide a micro-organism trap or barrier and a diminishing oxygen gradient down to the culture medium, the dimensions of the ducts, cahnula, culture medium and crosssectional area of the container adjacent its access opening, being specified; (2) the passageway through cannula 24 z is initially plugged air-tight with a viscous material 52, such as a mixture of petroleum jelly and paraffin, that is capable of yielding under a predetermined gaseous pressure generated by the (anaerobic) fermentation; and (3) the container 53, Fig. 8, is large and self supporting. |