726 A GUIDE FOR STUDENTS OF MICROTOMY 

 1424. General Plan of Procedure Applicable to Histological Specimens. 



Anaesthetise animal, kill it, quickly take out organ, cut pieces 1 cm. x 1 cm. x i cm. 



Fix for 24 hours in Zenker's fluid \ 5 % HgCU 



^ ( 5 % Gl. Acetic acid. 



Washing in running water 24 hours. 



Freezing Method. \ Paraffin Method. 



Preserve in 5% Formalin 



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Wash in water 



Cut sections with freezing microtome 

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Float in water on to slide 



Stain with Picro-carmine 15 minutes 

 Drain off and wipe away the stain around 



Mount in Farrants' medium. 



Pass through increasing strengths of alcohol 



70% alcohol 



Remove Hg deposit with iodine in 70% alcohol 



(Preserve in 70 % alcohol) 

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Stain 



Pass through 90% alcohol 1 day 



^ Dehydrate in abs. ale 1 night 



Clear in xylol or benzol From 1 to 2 hours 



Pass through xylol satd.with paraffin wax 1 hour 



Impregnate with paraffin at 52° C 2 hours 



and 

 Imbed and make blocks 



Cut sections with microtome 



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Celloidin method. 



Ale-ether aa 1 day 



Thin celloidin : 1 week 



(15% in ale-ether) 



Thick celloidin 1 week 



(30% in ale-ether) 



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After evaporation, mount on block of vul- 

 canised fibre. 



Harden celloidin in chloroform 1-2 hours 



and then in 80% ale 1-6 hours 



Cut with razor (oblique) wetted with 80% ale. 



1° Apply glycerin and albumen water to 

 slide 



2° Float section on sUde 



Warm gently to open out the section 

 Wipe away excess of water and dry in 

 warmth overnight 



3° Remove paraffin with xylol 



4° Remove xylol with abs. ale. 



5° Pass through 90 and 70% alcohol to water 



6° Stain in hsematoxylin, etc., 5-15 minutes 



7° Wash in water, 5 minutes— 1 hour 



Stain without removing celloidin 



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(Remove celloidin with oil of cloves) 



Mount in balsam. 



8° Counterstain in eosin — 1 minute 

 9° Remove excess with 90% alcohol 



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10° Dehydrate with abs. ale. 

 11° Clear in xylol 

 12° Mount in balsam. 



(Modified from D. T. Harris' " Practical Histology.") 



