Which fluid is used as a dehydrating solution for larger tissues?

The appropriate choice for a dehydrating solution for larger tissues is ethyl alcohol. Ethyl alcohol is widely used in histology for the dehydration process because it effectively removes water from biological tissues, which is crucial for the subsequent infiltration step with paraffin wax. This dehydration process helps preserve the tissue morphology and prepares it for sectioning.

In contrast, 10% formalin and 10% formol-saline are primarily fixation solutions. They preserve tissue structure and prevent decay by cross-linking proteins but do not serve the purpose of dehydration. Dimethyl sulfoxide, while a useful solvent in various applications, is not traditionally employed as a dehydrating agent in histopathology.

For larger tissues, ethyl alcohol allows for gradual dehydration, minimizing the risk of tissue damage that can occur if dehydration occurs too rapidly or with inappropriate agents. Thus, ethyl alcohol is the established standard for dehydrating larger tissue specimens prior to embedding and sectioning.