One approach that can be applied to an instrumented system for microbiological analysis is pulse-height analysis (PHA). The present prototype system is a semiautomated system composed of three major components including a sensor, pulse-height analyzer, and a recording unit. The PHA contains all the electronics required to count, classify as to size, and store the pulses received from the sensor. The PHA also contains the controls for the operation of both the sensor and recorder. There are several practical considerations related to the design and use of a pulse-height analyzer. They are Counting Solutions, Cell Counting, Sample Container, General Comments, Other Pha Instrument Systems. Curby's prototype instrument system employs the pulse-height analyzer to perform complete microbiological analysis of urine for detection of bacteriuria, antibiotic susceptiblity, and identification of the predominating pathogens in about 4 hr. The degree of automation of the pulse-height-analyzer system thus becomes a trade-off between feasibility and desirability.