Decalcificalion 29 



DECALCIFICATION-DEHYDRATION 



Jenkin's fluid (Culling, 1957): 



absolute ethyl alcohol 73.0 ml. 



distilled water 10.0 ml. 



chloroform 10.0 ml. 



glacial acetic acid 3.0 ml. 



hydrochloric acid, concentrated 4.0 ml. 



The swelling action of the acid is counteracted by the inclusion of 

 alcohol. Large amounts of solution should be used, 40-50 times bulk 

 of tissue. After decalcification, transfer to absolute alcohol for several 

 changes, then clear and embed. 



The major portion of this book will be devoted to sectioning methods 

 for preparing tissue for staining, because of complexity and quantity of 

 such methods. Brief mention, however, should be given to other means 

 of examining tissues. 



Exceedingly thin membranes can be examined directly by mounting 

 in glycerol or other aqueous media. Considerable detail can be observed 

 \vith reduced light or under the phase microscope. Sometimes a bit of 

 stain can be added to sharpen or differentiate certain elements. More 

 permanent preparations can be secured with fixation as discussed in 

 the preceding pages. 



"Touch" preparations are made by pressing the cut surface of fresh 

 tissue against a dry slide. Cells adhere to the surface and can be exam- 

 ined unstained, or the slide may be immediately immersed in a fixative 

 and then stained. 



Occasionally, free-hand sections of relatively tough tissue are cut for 

 examination. 



Smears are one of the commonest devices for simple slide prepara- 

 tion: blood and bone marrow (page 219), Papanicolaou (page 357), 

 fecal (page 386), and chromosomes (scjuash preparations, a modification 

 of smears, page 367). 



"Cell blocks" — concentrated clusters of individual cells or grouped 

 cells — are described in detail on page 38. 



