CHAPTER XXXVIII. 



559 



1049. General Plan of Procedure Applicable to Histological Specimens. 



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



( 2 % K 2 Cr-2 O 7 



5~ % Hg Cl? 

 ( 5 % Gl. Acetic acid. 



Wash in running water 24 hours. 



Fix for 24 hours in Zenker's fluid 



Freezing method. 



Paraffin method. 



Preserve in 5% Formalin 



f 



Wash in water 



Pass through increasing strengths of ale. 



f 



70% alcohol 



Impregnate with gum 



f 



Cut sections with freezing microtome 



Float in water on to slide 



f 



Stain with Picro-carmine 15 minutes 

 Drain off and wipe away the stain around 



Remove Hg deposit with iodine in 80% alcohol 



f 



(Preserve in 80% alcohol) 



Stain 



t 



Pass through 90% alcohol .................. 1 day 



Dehydrate in abs. ale ................. 1 night 



Mount in Farrant's medium. 



Clear in xylol or chloroform... From 1 to 2 hours 



f 



Pass through xylol satd. with paraffin wax 1 hour 



Impregnate with paraffin at 52 C 2 hours 



and 

 Embed and make blocks 



f 



Cut sections with microtome 



Celloidin method. 



Ale-ether aa 1 day 



[1 Apply fixative to slide or glycerine and 

 albumen water] 



f 



Thin celloidin 1 week 



(15% in ale-ether) 



Float section on drop of water on slide 

 Warm gently to open out the section 

 Wipe away excess of water and dry in air 



rhick celloidin ......................... ..1 week 



(30%- in ale-ether) 



3 Remove paraffin with xylol 



After evaporation, mount on block of vulcanised 

 fibre 



Harden celloidin in chloroform ......... 1-2 hours 



and then in 80 % ale ...................... 1-6 hours 



f 



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



4 Remove xylol with abs. ale. 



I 



5 Pass through 90 and 70 % alcohol to 

 water 



t 



6 Stain in Hsematoxylin, etc., 5-15 minutes, 

 etc. 



Stain without removing celloidin 



I 



(Remove celloidin with oil of cloves) 



Mount in balsam. 



7 Wash in water, 5 minutes 1 hour 



t 



8 Counter-stain in Eosin 1 minute, etc. 



t 



9 Remove excess with 90% alcohol 



i 



10 Dehydrate with abs. ale. 

 11 Clear in clove oil or xylol 

 12 Mount in balsam. 



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



