Applications of image intensification to low level fluorescence studies of living cells

Microscopic observations of weak fluorescence from living cells can be achieved by using image intensification techniques in situations where conventional film recording is not feasible. A brief description is given of experimental arrangements that have been used, involving recording the intensifier output alternately on film, or TV vidicons. References are given to more detailed descriptions of particular systems, and an example is presented of the detection of Ca++ in Haemanthus by means of the fluorescence of chlorotetracycline.