Microdiffusion chambers permitting the oil-immersion microscopy of growing microorganisms.

There is an obvious need for a technique whereby the medium surrounding an organism under microscopy can be altered without displacing the organism from the field. For example, we are interested in observing the same organisms before, during, and after exposure to various agents. Our general solution is to confine the organisms within a microchamber separated from the well of a well-slide by a semipermeable membrane through which the concentration of convenient reference if observations are to be made in more than one chamber. Input and output channels are ground into a Fisher-Littmad well-slide; this slide is only 1.2 mm thick, and the well has an optically flat bottom. If the grin is fastened flush with the underside of a no. 1 cover slip, there is no problem with standard 97 X objectives. Depending upon the microscope, it may be necessary to change the condenser; the photomicrographs shown here were taken