Combined Carbowax-Paraffin Technic for Microsectioning of Fixed Tissues

A combined Carbowax-paraffin technic for microsectioning fixed tissues gave ribbon sections as do paraffin infiltrated and embedded tissues. Blocks of formalin or alcohol fixed tissues 2 mm. thick were infiltrated with H.E.M. (Polyethlene Glycol: Carbowax, Hartman-Leddon Co.) or with one of the following polyethylene glycol ester waxes (Glycol Products Co., Inc.) for 4 hours at (61°C.): Polyethylene Glycol 600(Di) Stearate; Carbowax 1000-(Mono) Stearate; Carbowax 4000 (Mono) Stearate; Carbowax 4000 (Mono) Laurate; Carbowax 6000 (Mono) Oleate. The Carbowax infiltrated tissues were placed for 10 minutes in xylene (61° C.), into paraffin (61° C.) for 30 minutes, then into molten paraffin contained in separate molds. (The xylene passage can be excluded for preparations which preclude its use). The blocks were hardened rapidly by submerging in ice water and were fastened to carriers as in the usual paraffin technic. Tissues were cut 6 µ thick. Segments of ribbon were spread on a water bath and mounted on slides. After drying, tissues were stained directly with hematoxylin-eosin or were carried through xylene and alcohols as in routine paraffin preparations prior to staining. The Sudan III fat stain and Best's carmine stain for glycogen were applied as in usual technics. Cellular detail was well preserved and structures did not show the extent of distortion and shrinkage encountered in ordinary paraffin technic preparations.