630 General Notes. [June, 
leaving a rectangular surface of paraffine, two edges of which are 
parallel to the edge of the knife. 
A slide prepared by being painted with æ ¿kin coat of Schalli- 
baum’s mixture of collodion and clove oil is placed at the left of 
the microtome. 
At the right of the latter, handy to the right hand, is a small 
bottle half full of the thin collodion, into which dips the tip of 
a camel’s hair brush; the quill of the brush is thrust through a 
hole in a thin flat cork which serves at once as a temporary cover 
to the bottle and a support to the brush, the latter being adjusted 
to any height of the collodion by simply shoving it up or down 
through the hole in the close-fitting cork. Near by is a small bot- 
tle of ether with which the collodion is thinned as soon as it be- 
gins to leave a shining surface on the paraffine. 
The operator should sit facing the light, so that he may judge 
accurately of the condition of the surface of the paraffine, which 
reflects the light. Everything being in readiness the brush is 
lifted and wiped on the mouth of the bottle to remove the most of 
the collodion, and then the paraffine and object are at once painted 
by quickly drawing the brush across the surface, care being used 
that it is evenly applied and that the collodion is not carried on to 
the vertical faces of the block. The temporary moistening vanishes 
like a clond from the surface of the paraffine, the brush is re- 
turned to the bottle at once; the knife is drawn and returned, 
leaving the section on the edge of the blade. The object in the 
block is then painted again, but before drawing the knife a second 
time the first section is removed with a scalpel and placed on the 
slide with its upper face in contact with the fixative. Then the 
knife is drawn again, and the other steps of the process repeated. 
Thus the collodion has time to thoroughly dry before the section 
is made, But if the precautions above given are observed, it will not 
be necessary to wait for the drying of the collodion and the sec- 
tion may therefore be cut at once, z. e., within five seconds after 
painting. It is thus possible to cut as fast as one can paint the 
surface, and with some practice it becomes possible to cut con- 
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tinuous ribbons of sections which may be transferred at intervals. 
‘Practically I find it most convenient to cut enough to form one 
row or half a row of sections at a time and transfer at once to the 
