Celestine Blue B-Eosine-stained Intestine 217 



of course, have been prepared some time before. The melting point of 

 this medium is about 56° C. The oven should contain three stender dishes 

 (see Fig. 76) as well as a 500-ml beaker containing about a pound of 

 the embedding medium. The object is removed from benzene, drained 

 briefly on a piece of filter paper, and placed in one of the stender dishes, 

 which has been filled to the brim with the molten embedding medium. 

 Under no circumstances should a lid be placed on the stender dish be- 

 cause it is desirable that as much as possible of the benzene should 

 evaporate while the process of embedding is going on. After about 3 hr 

 the specimen should be removed to fresh wax in the second stender dish, 

 where it may remain about 2 hr, and then to the third stender dish, 

 where it should not remain for more than 1 hr. 



Shortly before the end of this last hour, a decision should be made as to 

 what type of vessel is to be used for casting the block. It would be diffi- 

 cult to improve on a paper box for this object. When the box is made 

 (it should be of ample size), it is moistened at the bottom and placed on a 

 slab of glass in the manner described in Chapter 12. It should then be 

 filled about halfway with embedding material from the beaker and al- 

 lowed to remain until about half of this wax has congealed on the bottom. 

 An object like the one under discussion is better handled with old forceps 

 than with a pipette. The forceps should be warmed in a flame to well 

 above the melting point of the wax and moved backward and forward 

 across the surface to melt the solid film that has formed. Then the object 

 is picked up rapidly from its stender dish, placed in the wax, and enough 

 fresh wax from the beaker added to make sure that there will be as much 

 solid wax above as there is underneath the specimen. Blocks of this nature 

 shrink greatly, and it will probably be best to fill the box entirely. As soon 

 as the box has been filled, the forceps should be warmed again and passed 

 backward and forward around the object to make sure that no film of 

 unmolten wax, which would cause it to cut badly, remains. The wax in its 

 box should now be blown on until it starts to congeal on the surface. Then 

 it is picked up very carefully with the fingers and lowered into a dish of 

 water at room temperature (the water does not quite reach the top of 

 the box). If it is thrust under the surface at this point, all the molten 

 wax will come out and the block will be useless. As soon as the block 

 has congealed throughout, it is thrust under the surface of the water 

 and something is laid on it to keep it at the bottom. It should be left 

 in the water for at least 5 or 6 hr, or, much better, overnight. 



The block should be trimmed so that there is at least as much wax on 

 each side of the object as there is in the object itself. This amount of wax 

 would be excessive for serial sections, but for the preparation of indi- 

 vidual sections of this type in an example given for the benefit of the be- 

 ginner, this quantity is desirable. When the microtome is set up and the 



