These small pieces are called histological blocks of biological tissues are embedded in paraffin wax, that facilitates their sectioning on a slicer (called a microtome) into super-thin slices that can be subsequently stained in dyes for observation under the light microscope. 

A pair of unscientific looking glasses contain specialized lenses that prevent the transmission of high energy light, like UV light or even parts of the visible light spectrum e.g., blue light. We wear these glasses in our lab when we irradiate our tissue and cell samples with high-energy light, in order to protect our eyes from damage that can lead to cataracts and macular degeneration. 

This rather unassuming empty plastic bottle once contained so-called OCT (or ‘Optimal Cutting Temperature’ embedding medium. This was used to embed frozen pieces of body tissue to support it during fine slicing, before collection of the sections onto a microscope slide for staining and observation.  Another way to support tissue at room temperature before slicing is to embed it in paraffin wax, as can be seen in these two small tissue holders.