MEDICAL AND BIOLOGICAL STAINING TECHNIQUES 



black. Neuroglia fibres and erythrocytes, red. Medullary sheaths 

 are unstained. Connective tissue, deep green. Nerve cells are 

 pale green with red stippling, while nerve-cell nuclei are a darker 

 green with bright red nuclei. 



Notes: 



(a) The material must be fresh and only small pieces should be 

 employed. 



{b) Sections stained by this technique should appear lilac in 

 colour to the naked eye. 



{c) It is advantageous to experiment in order to determine the 

 optimum staining time in the picric acid and the light green, as 

 results vary according to the material to be stained. 



From Pathological Technique by F. B. Mallory, by courtesy of Messrs. W. B. 

 Saunders Co., Philadelphia, U.S.A 



LIGNIN PINK 



For whole mounts of marine invertebrates, particularly for 



crustaceans limbs, ostracod appendages, Medusa of Obelia, 



etc., as well as for demonstrating chitin 



Overstaining with lignin pink is impossible, and it will not wash 

 out with alcohol. 



Solutions required: 



A. Sea water Bouin: 



Sea water saturated with picric acid 75 ml. 

 Formaldehyde 40% . . . . • • 25 ml. 



Glacial acetic acid . . . . • • 5 ^' 



B. Lignin pink saturated in distilled water or 

 in Benzyl alcohol. 



Technique: 



1. Specimens are fixed from eighteen to forty-eight hours, 

 according to the material, in Solution A. 



2. Wash out the fixative with 50% alcohol, followed by 70% 

 alcohol until the yellow coloration, due to the picric acid, is com- 

 pletely extracted. 



3. Wash in running water to remove the alcohol. 



4. Immerse in solution B for fifteen minutes or longer. 



140 



