Results obtained by staining plasmalemmata and mucilage with phosphotungstic acid (PTA) are described. Plasmalemmata are strongly contrasted by staining with PTA and it is possible to study the way in which the membranes of the secretory vesicles are restructured. Contrary to what has already been reported for Drosera capensis, structural alteration of the membranes only starts at the moment when the vesicles open in the periplasm.
In addition, the author confirms the very great affinity of PTA for mucilage and compares the images obtained with this stain with those observed subsequent to Thiery's reaction.