In the context of the conditioning of histological samples for later microtoming, in particular in the preparation of histological samples in the context of an embedding process, they are firstly fixed by the application of various chemicals. The tissue liquid originally present in the natural cavities of the sample is thereby replaced, in multiple steps, by a fixing liquid, for example by formalin. In order to convert the fixed samples into a state that permits sectioning by means of a microtome, the fixing liquid is replaced by an embedding medium, for example paraffin, gelatin, agar, nitrocellulose, polyester wax, polyethylene glycol, or plastic. During the aforementioned processes, the samples are usually located in a cassette that comprises a plurality of sieve-like openings so that the chemicals can flow around the samples. A particular embodiment of such a cassette is known, for example, from DE 43 33 118 A1.
After infiltration of the embedding medium into the samples, the excess paraffin is drained off. After this step, the samples can be located anywhere within the cassette; because of the paraffin residues adhering to them, the samples as a rule adhere to the cassette cover, in the cassette cavity, and/or to one another.
Before further processing, in particular for automated, machine-controlled further processing, namely casting the samples into a paraffin block (called “blocking”), the samples must be separated and removed from the cassette. In order to allow the samples to be separated from one another and removed from the cassette, the paraffin that causes the aforementioned adhesion must be melted again. For this, the cassette (in the closed state or in the flipped-open state) can be introduced into a paraffin bath. This must occur largely without jolting. In addition, contamination and functional impairment due to solidifying paraffin must be avoided.
DE 10 2008 039 875 A1 discloses a method and an apparatus for infiltrating tissue samples with paraffin. The apparatus comprises a retort that is embodied as a closable chamber and that can be filled, in valve-controlled fashion via conduits, from a reservoir container of paraffin. For this a vacuum is applied to the closed chamber of the retort so that paraffin is conveyed through the conduit and through special distributors and valves into the retort. In particular because the samples, and the cassette in which the samples are arranged, are not accessible during flooding of the retort, an apparatus of this kind is unsuitable as a paraffin bath for detaching or isolating samples adhering to one another, or samples that are adhering in the interior of a cassette.