ImageJ and Volume Measurement - Cavalieri's principle

Hello, I am trying to prepare an analysis of the brain volume (detailing the hippocampus) by using the Cavalieri principle.
We used a modified version of the fractionator method (West, 1993; Nacher et al., 2002; Varea et al., 2007). We counted all labeled cells within each section, covering 100% of the sample area in the different subdivisions and layers. The fractionator sampling scheme refers to examining one out of every six 50μm-thick randomly selected section. The images used for the analysis were obtained with a confocal microscope (Olympus FV-10)

I used to use the “Volumex” plugin for this purpose, but I cannot find it in ImageJ now. Does it still exist?
Is there another plugin that allows measuring the volume using this method?
Thank you for your help