Chromosomes 367 



results: 



sex chromatin — red 



other nuclei, vesicular and cytoplasm — green 



comments: 



In the long method, the hematoxylin mordants the sex chromatin 

 for biebrich scarlet and makes a firm binding, also slows do^vn the fast 

 green. 



Makowski et al. (1956) identified sex chromatin in the cellular 

 debris of amniotic fluid, spreading the centrifuged sediment on albu- 

 menized slides. Vernino and Luskin (I960) identified it in bone de- 

 calcified in EDTA. Barr et al. (1950) describe it in nerve cells. See 

 also: Klinger (1958); Marberger et al. (1958); Marwah and Wein- 

 mann (1955); Moore and Barr (1955); and Moore et al. (1953). 



Chromosomes 



Squash and Smear Technics with Acetocarmine or 

 Aceto-orcein Staining 



fixation: sometimes desirable. Use small pieces, Carnoy's (page 16), 

 freshly prepared, few minutes to several days. 



solutions: 



Acetocarmine: 

 Stock solution. 



Boil an excess (approximately 0.5 gm./lOO ml.) of carmine in 

 45% acetic acid, aqueous: 2-4 minutes. Cool and filter. 



Working solution: 



Dilute stock solution with 45% acetic acid, aqueous, 1:2. An 

 iron-mordanted stain often is favored because of darker, bluish- 

 tinged red. Belling (1926) added a few drops of ferric hydrate in 

 50% acetic acid, but only a few drops. Too much iron produces 

 a precipitate in a short time. Moree (1944) determined quanti- 

 tatively the amount of ferric chloride to add and includes tables 

 of various normalities and volumes. 



Aceto-orcein: 



Add 1-2 om. orcein to 45 ml. of hot acetic acid. When cool, add 

 55 ml. of distilled water. LaCour (1941) used 2% orcein in 70% 

 acetic acid. 



