SECTION TWO 



21. Blot away excess water but do not allow the section to dry. 



22. Mount in Farrant's medium, or in Aquamount. 



23. Attach a clip to hold the coverslip to the slide: then leave 

 overnight in the oven to harden the mounting media, before 

 examining the preparation under the oil immersion objective. 



Note: The slide may be examined after a quarter of an hour, if 

 desired; then returned to the oven to complete the hardening. 



Results* : 



Lipids, dark blue or blue-black. Cytoplasm : colourless or pale 

 grey-blue. Chromatin: pink or red. 



Note: If the results are not good, another section should be tried 

 with variations of the staining times. 



Never attempt to judge the colouring until the section is 

 mounted and examined under the oil immersion objective. 



It is recommended that the technique be learned on the intestine 

 of the mouse, as it is scarcely possible to fail with this. Cut out a 

 piece of empty intestine about i cm. long and immerse in for- 

 maldehyde-saline for five minutes, then open it by a longitudinal 

 cut from one end to the other, taking care not to do any unneces- 

 sary damage to the villi. 



The section should be left only one minute in the Sudan black 

 and two and a half minutes in the carmalum. 



Reference: Baker, J. R. (1949), Q.jf.M.S., 90, 293-307. 



* In the original paper the method refers to " Golgi bodies ". Dr. J. R. 

 Baker, to whom I am indebted for permission to include this abstract, informs 

 me (March, 1955) that he regards the method as essentially for those lipids 

 that are not well stained by other Sudan colours. In the original paper it is 

 stated: " Simple Golgi bodies and externa: dark blue or blue-black. Golgi 

 vacuoles: colourless ". The changes are Dr. J. R. Baker's. 



SUDAN BLACK 

 A specific stain for neutral fats 



Solutions required: 



A. Sudan black, saturated in 70% 



alcohol. 



B. Carmalum (Mayer). 



Technique: 



Tissues are fixed at least three days in 10% formalin; then 

 rinsed thoroughly in distilled water. 



207 



