420 BLOOD AND GLANDS 



Janus Green Method. See § 761. Islets deep blue on a red 

 background. 



Pyronin Method for Ducts. Inject a 1 in 1000 solution of 

 pyronin, as above, for neutral red method. The ducts stain 

 intensely red. Double stains may be made by injecting mixed 

 Janus green and pyronin (Bensley, op. cit.). 



Methylen blue, 1 in 10,000, may also be used for this purpose. 

 After injection fix in 5 per cent, ammonium molybdate, for which 

 see also Chapter XVIII. 



Grand-Moursel and Tribondeau (C. R. Soc. Biol., liii, 1901, 

 p. 187) recommend for pancreas Nicolle's " thionine pheniqu^e," 

 which stains the insulae of Langerhans hardly at all, the rest 

 strongly. 



Lane's Methods for Demonstration of A Cells of the Islets of 

 Langerhans. 1. Fix tissue for from two to four hours in equal 

 parts of saturated alcoholic solution of mercuric chloride and 2\ 

 per cent, potassium bichromate. Wash in 50 per cent, alcohol, 

 then upgrade and imbed ; Sjit sections are stained in neutral 

 gentian, obtained by precipitation of equivalent solutions of 

 gentian violet (crystal violet) and orange G. If the correct 

 quantity of the latter is added to the former, a practically com- 

 plete precipitation is obtained. The precipitate is soluble in 

 alcohol or acetone. For staining add the stock alcohol solution 

 to 20 per cent, alcohol until a solution having the colour of good 

 hsemalum is obtained. Allow to stand for twenty-four hours. 

 Stain for twenty-four hours, blot, dehydrate in acetone, toluol, 

 differentiate in absolute alcohol 1 part, oil of cloves 3 parts, 

 wash in toluol, and mount in balsam. 



2. Fix in 70 per cent, alcohol, then stain in neutral gentian as 

 ^bove. 



Lane's Methods for Demonstration of B Cells of Islets of 

 Langerhans. Fix for four to twenty-four hours in : — 



KgCraOj 2-5 grm. 



HgClg 5-0 „ 



Aq. dest. ...... 100-0 c.c. 



Dehydrate, clear, imbed, and section ; stain in neutral gentian 

 as above. 



Formalin Bichromate Method for Fixation. This gives a very 

 regular and reliable fixation, and is suitable where one is carrying 

 out observations which necessitate a successful routine method. 

 Bensley [op. cit) uses 10 c.c. of neutral formalin to 90 c.c. of 

 Zenker's fluid without acetic acid, for twenty-four hours. Stain 

 in neutral gentian, acid fuchsin and toluidin blue, iron hsema- 

 toxylin or Mallory (§ 961). 



HoMANS {Journ. Med. Research, xxx, 1914), used Bensley's 

 modified Altmann fixative (OSO4 of 4 per cent., 2 c.c. ; potassium 

 bichromate of 2-5 per cent., 8 c.c. ; glacial acetic acid, 1 drop), 



