APPENDIX. 367 



is then poured on the glass to solidify the lower 

 portion of the mixture, and just when a thin crust 

 is forming on the upper surface, the space is tilled 

 up with the mixture and the tissue placed in it. 

 The layer next the glass is by this time solid, and on 

 this the tissue can be arranged with a warm needle 

 in any position required. 



An oblong box made out of not too thin paper may be 

 used instead of the pieces of lead. 



The sections, in this case, are best cut with a razor 

 moistened with olive oil. The imbedding mixture 

 must be dissolved out, e.g. with creosote and turpen- 

 tine; if it is desired to mount the sections in 

 glycerine, they should be placed in absolute alcohol 

 to remove the creosote and turpentine, they can then 

 be mounted at once or after having been placed in 

 more dilute spirit. 



Before cutting sections, cut away the imbedding sub- 

 stance close around the tissue. It is easier to cut 

 thin sections when the surface to be cut is small 

 than when it is large. 



In preparing the following mixtures, the constituents 

 should be placed in a capsule on a water-bath and 

 kept at a temperature just above melting point for 

 an hour or more, the liquid being occasionally 

 stirred. 



Paraffin A. 



Solid paraffin 15 grms. 

 Liquid paraffin 15 c.c. 



This is used to surround the cover-slip in observing 

 the amoeboid movements of white blood-corpuscles, 

 on the warm stage. It begins to melt at about 



