. Clinical bacteriology and haematology for practitioners. Bacteriology; Hematology. THE PARAFFIN PROCESS 187 completely melted, but always shows a thin solid layer on the surface. To do this it is only necessary to look at the bottle occasionally, and move it a little further from the fire if the paraffin is completely melted, and vice versa. The process may be stopped at night without any harm resulting, and if the soakmg only continues for a few hours at a time it is of no consequence so long as the total period is made up. Casting the Blocks.—Special metal moulds are used in the labora- to
. Clinical bacteriology and haematology for practitioners. Bacteriology; Hematology. THE PARAFFIN PROCESS 187 completely melted, but always shows a thin solid layer on the surface. To do this it is only necessary to look at the bottle occasionally, and move it a little further from the fire if the paraffin is completely melted, and vice versa. The process may be stopped at night without any harm resulting, and if the soakmg only continues for a few hours at a time it is of no consequence so long as the total period is made up. Casting the Blocks.—Special metal moulds are used in the labora- tory (Fig. 37). A pill-box will do quite well. A small amount of melted paraffin is poured into the box, and the piece of tissue is taken from the bottle containing the melted paraffin with a pair of forceps (previously warmed, so as to prevent the paraffin from setting upon the points), and placed in the paraffin in the pill-box. It is necessary to see that the surface from which sections are to be cut should be placed downwards. The box is then filled up with melted paraffin, and placed in a cool place or surrounded with. Fig, 37.—L-sH.^PED Moulds for embedding c P.^raffin. water. The moment a firm film has formed over the surface the whole is plunged in cold water to hasten the setting of the paraffin ; the more rapidly this takes place the better will the block cut. When the paraffin mass has hardened completely throughout, it is trimmed into shape, taking care that the edges of the surface which is to be cut are accurately parallel. Cutting the Sections. — For cutting sections in paraffin no microtome can be compared with the Cambridge Rocker, but very excellent results can be obtained by the use of the Cathcart microtome already mentioned. The paraffin block containing the piece of tissue is mounted on the freezing-plate of the microtome (which must be heated, and the lower surface of the block pressed upon it), and the sections cut in the manner described ; a very sh
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Keywords: ., bookcentury1900, bookdecade1910, booksubjectbacteri, bookyear1912
