290 SANTE NACCARATI 



or Hermann's fluid. The sections must be very thin, about 

 4 or 6 M. 



The technique is as follows : 



1. The section is stained from five to ten minutes at the tem- 

 perature of 50°C. with a freshly prepared saturated solution of 

 fuchsin in aniline water. 



2. Wash in water for about thirty seconds. 



3. Transfer to a semisaturated solution of picric acid in 

 50 per cent alcohol for twenty or thirty seconds. 



4. Prolonged wash in water until the section does not yield 

 any more picric acid. 



5. Staining for four or five minutes with a ^ per cent solution 

 of methyl green in 90 per cent alcohol. 



6. Rapid transfer to grades of alcohol, during which the 

 sections yield much stain. 



7. Transfer to xylol and mount. 



Sections thus prepared show the following characteristics: 

 The nuclear chromatin, the centrosomes, and the granules of 

 secretion are bright red, the protoplasm and the connective 

 green. The strongly basophile substances, such as mucin and 

 chondrin, take also a green, but more intense stain. The picric 

 acid, acting as a mordant on the methyl green, renders it a 

 plasma dye. In good sections the plasma takes an emerald 

 green stain. If it takes a yellowish-greenish stain, the section 

 can be utilized, provided that the fuchsinophile granules take a 

 distinctly bright red stain. Sometimes (either because of a 

 much prolonged action of the picric acid or for other reasons) the 

 section does not stain at all with methyl green. It is advisable 

 to repeat this method several times until a good section is 

 obtained. 



Figure 4, showing only a part of the epithelium of the vesicle, 

 gives the appearance of a few cells stained with the method 

 of Galeotti. 



