The assembly and use of an automatic turbidity recording device.

Bacteriologists have used turbidimetric estimation of bacterial growth for many years. With the advent of the photoelectric and spectrophotometric methods, the precision of such measurements was improved. Gavin (1957) has discussed in detail certain fundamental considerations of the turbimetric method. In common with most growth measurements, final population densities were the common criterion used. Hourly readings, for example, entailed a great deal of tube handling plus the need for constant attention by laboratory personnel. This paper describes the assembly from readilv available equipment of a device for recording automatically the turbidity of a large number of culture tubes at hourly intervals throughout the incubation period.