G80 SUAIMARY OF CQRRENT RESEARCHES RELATING TO 



It is clear from what has preceded that a shorter cup or trough filled 

 with soft paraffin melting at 36° C. may be placed still farther away from 

 the burner, alongside of the vessel containing hard paraffin fusing at 56° C, 

 while mixtures of turpentine and paraffin, or chloroform and paraffin, would 

 remain molten at a still greater distance from the flame. 



The applications and possibilities of this new device will be readily 

 appreciated by histologists and embryologists, since it can be quickly seen 

 if objects are in danger from overheating by simply noting whether the 

 point where the paraffin remains molten in the trough has advanced farther 

 from the flame. This can be easily observed through the transparent 

 cover of the trough. 



For large laboratories, where a number of students are engaged in im- 

 bedding, a simple modification of this device suggests itself. For such a 

 purpose a horizontal disc of sheet copper, of the same thickness, but 

 3 ft. in diameter, would affijrd room for a large number of paraffin im- 

 bedding-troughs, which could be arranged in a circle around and some 

 distance from the centre, at which point a larger burner would be applied 

 underneath. The temperature in such a device would diminish from the 

 centre towards the periphery of the disc. The troughs would be placed 

 upon different radii upon the surface of the disc, just as two or three 

 troughs may be placed upon different radii of the triangular plate, which is 

 practically the sector of a disc, as described above. 



For imbedding delicate objects, small cups made of tin-foil, pressed into 

 shape in circular tapering moulds, may be satisfactorily employed with this 

 apparatus, in the same way as the troughs. 



'I'he device described above can be made by any coppersmith for about 

 two dollars. 



Imbedding Objects for the Rocking Microtome.* — Herr S. Schonland 

 advises the following method for imbedding objects in paraffin. It is 

 especially intended for use with the Cambridge rocking microtome, which 

 requires perfect saturation of the object with paraffin. The object, first 

 stained in borax-carmine, is placed in 30 per cent, spirit, to which a trace 

 of acetic acid has been added. It is then transferred to stronger and 

 stronger spirit. From the strongest alcohol it is transferred to a vessel 

 (holding 3-4 ccm.) half filled with oil of cloves and half with spirit. 

 When the specimen has sunk to the bottom, it is placed in pure cloves, and 

 after an hour in turpentine oil, wherein it remains for about six hours. It 

 is next immersed in paraffin for eight to ten hours. The temperature of 

 the paraffin, which has a melting-point of about 45° C, is not allowed to rise 

 above 47^, but just before imbedding it is advisable to heat the paraffin a 

 little more, as air-bubbles are thereby avoided. The ordinary paper boxes 

 are used for imbedding. 



Imbedding Eyes in Celloidin.t — Dr. W. B. Canfield recommends that 

 eyes should be hardened in Miiller's fluid and then after-hardened in spirit. 

 Schultze's diffusion apparatus is of great use for preventing shrinking of 

 the eye. A small incision is then made tangentially to the sclera and also 

 on the corneal edges, and the eye put in equal parts of absolute alcohol and 

 sulphuric ether. After twenty-four hours it is transferred to pure ether, 

 and the next day to a thin watery solution of celloidin in ether. In order 

 to get rid of air-bubbles, the eye is to be so immersed that the incisions are 

 uppermost. After twenty-four hours the eye is j)ut in thick celloidin, the 

 vessel beincr left partially uncovered, until the celloidin is hard enough to 



♦ Bot. Centralbl., xxx. (1887) pp. 283-5. 

 t The Microscope, vii. (1887) pp. 99-101. 



