Abstract: Water soluble reagents are claimed, comprising a water-soluble polymeric carrier molecule having attached thereto more than one connecting moiety wherein the connecting moiety is derived from divinyl sulfone, and wherein each connecting moiety is attached to a reactive functional group on the polymeric molecule, and wherein the reagents are capable of reaction with a molecular species having a functional group which is reactive towards the terminal vinyl group of the more than one connecting moiety and the molecular species is selected from the group consisting of labelling species, marking species, and targeting species.

Abstract: A tissue staining cassette includes a container for reagent, a slide retainer for securing a plurality of slides and for suspending the slides in reagent in the container with tissue specimens immersed in the reagent. The slide retainer consists of an open ended cylindrical body having channel containing inserts disposed in the body with the channels opposed for receiving the edges of slides. Depending spring arms corresponding to each of the channels are affixed in the cylindrical body and the end of each spring arm extends into its respective channel. As slides are inserted into the channels the spring arm is displaced and responsive to the displacement the slide is clamped between the end of the spring arm and a wall of the channel. In another embodiment resilient wall members extend across the bore of the slide retainer body to divide the bore of the retainer body into slide receiving areas corresponding to the opposed channels.