* 
1888. | 
exactly the size of the cylinder and putting this into the cylinder asthe 
bottom of the box. The object to be imbedded is placed horizontally 
upon the bottom and the melted paraffin poured over it, after which the | 
whole is placed in a shallow, flat-bottomed vessel filled with melted 
paraffin. Thus there is no possibility of the paraffin’s escaping, which 
otherwise it is almost impossible to prevent, and there is also no neces- 
sity of handling the objects after they are once in the paraffin, which, in 
‘the case of small objects, is a great advantage. In case the objects are dis- 
placed in pouring the paraffin over them it is a simple matter to adjust 
them, using a heated needle for this purpose. 
In order to insure thorough saturation the objects were usually left ~ 
over night in the melted paraffin, and then, as in the articles mentioned, 
: quickly cooled to avoid the formation of bubbles. The vessel containing 
the paper boxes may be exposed to the air for a few minutes until a thin 
film has formed over the surface of the paraffin in the latter, when these 
may be quickly lifted out and plunged into cold water. As soon as the 
paraffin is thoroughly hard, the pasted seam in the paper cylinder may 
be loosened with the blade of « knife or scalpel, when it will be found tee 
that the paper separates readily from the inclosed paraffin, and on remoy- 
ing the bottom of the box in the same way the result is a solid cylin- 
drical block of paraffin with the object to be cut lying horizontally close 
to the smooth lower face, so that the sectioning is easily regulated. 
Schénland‘ recommends paraffin with a melting point of about — 
48 ©., but I found this much too soft to cut well, and prefer, as Moll 
tr Series of sections, a very desirable thing in embryological investi- — 
ations, 
Moll’ describes fully the fixing processes, but my experience has been 
that it is not desirable to hasten the staining process. Safranin was 
Mainly used, and the best results were had by allewing the sections to 
th r about twenty-four hours in a very dilute watery solution. At 
* end of this time they should be deeply stained. The slide is then 
Piunged in absolute alcohol until the excess of the color is removed, and 
Mes _ accomplished and most of the alcohol has been removed 
om the slide with a cloth or blotting paper, taking care of course not to 
until a ee a few drops of xylol is applied and allowed to remain 
: Sections look perfectly transparent, when a drop of Canada 
put dissolved in xylol or chloroform may be applied and a cover-glass. 
aS the preparation, which is now complete. 
‘Lie, 
eL. ¢, 
BOTANICAL GAZETTE. I§Q°) 3 
