496 APPENDIX. 



with potassic iodide, and then add enough iodine to 

 make a dark sherry-coloured solution. The object to be 

 stained must be placed in a little water, and then some 

 of the above solution added. 



27. Silver Nitrate, Solution of.* 



Dissolve 0-5 grammes of silver nitrate in 100 cubic cent, 

 of distilled water. Keep in an opaque stoppered bottle. 



28. Sodic Chloride, Solution of. (Normal saline Solution. 

 Salt solution.} 



Dissolve 7*5 grammes of sodic chloride in i litre of 

 distilled water. 



F. SECTIONS AND SECTION CUTTING. 



Directions for preparing sections of the vegetable tissues will 

 be found incorporated in the text ; those which follow apply to 

 the animal series alone. 



1. Imbedding. 



All tissues or embryos about to be imbedded, whether 

 stained or unstained should have been first well hardened 

 in 90 p.c. alcohol. 



For imbedding, a mixture of hard and soft paraffins is 

 most serviceable, such as shall melt at from 50 to 60. 



The preparation to be imbedded, if stained, should be 

 first soaked in turpentine to saturation; if unstained, it 

 may be transferred direct from the alcohol. In either 

 case it must be placed in melted paraffin (the temperature 

 of which must not exceed that of its melting point) until 

 thoroughly permeated thereby. When ready for imbed- 

 ding, take of the solid paraffin a piece of about the 

 calibre of a candle and excavate at one end a pit, large 

 enough to fully accommodate the preparation ; then 

 transfer the latter and fill the pit with melted paraffin. 

 Put the whole aside, until quite cool and firmly set. 



2. Cutting. 



For this purpose an ordinary razor will suffice, so far as 



