Abstract: An apparatus for reconstituting dried bacteria includes a first reservoir for the storage of reconstituting solution, a pump via which the reservoir is coupled to one of a pair of hollow needles arranged side by side in operative association with an apparatus for raising or lowering the pair so that in use they can be lowered to pierce a closure bung of a container in which bacteria are sealed under vacuum, the one needle being effectively longer than the other of the two hollow needles so that consequent upon lowering of the pair, the one needle passes through the bung before the other effectively shorter of the two needles. The shorter of the two needles is coupled to a second reservoir for the transfer thereto, in use of the apparatus, of reconstitution solution from the first reservoir together with bacteria from the container.

Abstract: A method of obtaining small representative solid-phase samples from a large solid-phase sample. Solid-phase material is optionally separated from any liquid-phase that may be present and is mixed. A portion of the mixed solid-phase particulate sample is selected which provides an intermediate size representative sample. After adding liquid diluent to the intermediate particulate sample in a vessel, the suspension is agitated to promote separation of small particles as may be adhering to large particles to obtain a homogeneous suspension. Agitating is preferably carried out using a magnetic stirring bar. Fractions of this homogeneous suspension are then obtained by aspirating using a pipette and transferred to test tubes which will constitute small, truly representative solid-phase particulate samples from which replicate testing can be confidently performed.

Abstract: A method for compensating toxicity test data for the measured toxicity of a reference sample by the steps of:a. obtaining toxic response data for a plurality of concentrations of at least two different test samples, including reagent controls having zero sample concentration for each sample;b. defining the sample having the smallest toxic response at high concentrations as the reference sample;c. computing the toxic response of the test sample relative to that for the reference sample for at least two concentrations in accordance with the equation:relative gamma=.GAMMA..sub.R =(L.sub.SC /L.sub.SX)(L.sub.RX /L.sub.RC)-1, where L.sub.SC =light output of the test sample control (i.e. for X=0),L.sub.SX =light output of the test sample for concentration X,L.sub.RX =light output of the reference sample for concentration X,L.sub.RC =light output of the reference sample control (i.e. for X=0); andd. generating a dose-response curve of concentration versus relative .GAMMA.