Abstract: Procedure for the visual and microscopic study of the characteristics of a vegetable plant; characterized because it includes the stages of: collection and selection of specific leaves from the plant; submission of a leaf to a pressing operation at approximately 6 kg/cm.sup.2 and later drying at ambient temperature of approximately 30.degree. ; under these conditions the leaf undergoes soaking in a disinfectant solution; thereafter the leaf is placed between two plastic sheets or films and these are closed with sterilization at 125.degree. C. which temperature is appropriate to carry out the thermowelding which takes place at a pressure of 6 kg/cm.sup.2 to remove any possible air bubbles.