Cover member, method and treatment module for treating a biological sample on a substrate

A treatment module for use with a biological sample disposed on a substrate, the treatment module comprising:

• a cover member formed from at least two parts including a cover member body and a cover member insert coupled to the cover member body, the cover member having:
• opposing ends comprising a first end and a second end;
• opposing surfaces comprising a first surface and a second surface;
• and
• a fluid inlet toward the first end, extending through the cover member body and the cover member insert, and in fluid communication with the void;
• a support surface configured to support the substrate and a biological sample thereon;
• and
• a pivot arm operable to pivot the cover member between an open condition and a closed condition relative to the substrate,
• wherein the cover member insert is removably couplable with the cover member body, and wherein the cover member insert includes a void which, when juxtaposed with the substrate, forms a chamber.