Abstract: To characterize and differentiate large organic cells rapidly, individual particles are illuminated with monochromatic radiation of a wave length comparable to the size of the cell, producing a differential light scattering pattern about the illuminated cell. The pattern is sensed, preferably in the disclosed apparatus, by an array of detectors, and the sensed pattern employed as an identification and characterization of the cell. The pattern may be analyzed, or selected portions of the pattern employed, to differentiate cells embodying different features. The apparatus and process is especially useful for rapid identification and differentiation of leucocytes and other types of mammalian cells, the radiation for such analyses preferably being infrared radiation. A preferred structure for individually illuminating such cells with radiation and for sensing their differential light scattering pattern is disclosed.

Abstract: A programmable action sampler system (PASS) is described which holds a large number of discrete samples in a matrix of separate sample cups. The system is capable of dispensing a sample from a sample line into any one of the sample cups. At a pre-determined later time, using a cannula, the system addresses the sample from the cup for further measurement or analysis. In the preferred system, the samples flow sequentially through a tube, the liquid intermediate the samples being dispensed into a liquid waste line. The cannula between samples is bathed constantly in a wash tube, even while moving from one sample location to another. Further, in the preferred application, bacterial samples are employed, the sample cups being immersed in a constant temperature liquid bath to hold the bacterial samples at a constant incubation temperature. Among the various novel features employed in the system is a blade brake structure that accurately locates the sample head and cannula over any selected sample cup.

Abstract: A differential light scattering photometer is disclosed for testing samples of bacteria in suspension. A plurality of cuvettes containing the samples are placed in a cuvette holder or carousel which rotatably places each cuvette in position to interrupt a laser beam. A detector rotates in an arc about each sample to produce output signals representing the scattered light intensity as a function of angular location, relative to the incident laser beam, about the sample. A control differential scattering pattern is produced and compared with test differential scattering patterns derived from test samples having added antibiotics. The patterns are compared by data processing to produce an output punched card indicative of bacterial sensitivity to each antibiotic. The data processor is responsive, through pattern comparison, to various responses of the bacteria, i.e., whether the antibiotic is bactericidal, bacteriostatic or the bacteria actually metabolize the antibiotic.