ON EGGS OF MARINE ANIMALS 89 



Protocol III. 



Staining for mitocho?idria. 



Example of object: Eggs of Chaetopterus or of Nereis in 

 metaphase of first cleavage. 



Proceed as in Protocol II as far as 12. 



13. Carry slides from 50 per cent to 35 per cent alcohol. 



14. Wash slides in distilled water. 



15. Flood the slide with a saturated aqueous solution of 

 Fuchsin S. Warm the slide gently at 6o°C. for 2 to 3 minutes. 



16. Bring the slide into 95 per cent alcohol, saturated with 

 picric acid. Under low power of the microscope in daylight, 

 control the diflFerentiation, removing the slide when all color 

 has been discharged except in the mitochondria. 



17. Transfer the slide to 100 per cent alcohol for 3^2 minute, 

 then to toluene with two changes, each of 5 minutes. 



18. Mount the slide in neutral balsam. 



VViRE-o Binding Patents — 



21 16589-21 12389. 



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