396 BLOOD AND GLANDS. 



p. 187) recommend for pancreas NICOLLE'S " thionine pheniquee," 

 wliicli stains the insulse 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 mercury chloride, and 2J per cent, 

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

 and embed ; 3 jut sections are stained in neutral gentian, obtained by 

 precipitation of equivalent solutions of gentian violet (crystal violet) 

 and orange GL If the correct quantity of the latter is added to the 

 former, a practically complete 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 haemalum 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 

 above. 



LANE'S Methods for Demonstration of B Cells of Islets of Langerhans. 



Fix for four to twenty-four hours in : 



K 2 Cr 2 7 ...... 2'5 grms. 



HgCl 2 ...... 5-0 



Aq. dest . 100 -0 c.c. 



Dehydrate, clear, embed, 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 hsematoxylin 

 or Mallory ( 314). 



HOMANS (Journ. Med. Research, xxx, 1914) used Bensley's modified 

 Altmann fixative (Os0 4 of 4 per cent., 2 c.c. ; potassium bichromate 

 of 2*5 per cent., 8 c.c. ; glacial acetic acid, 1 drop), Lane's methods 

 (vide supra), and ordinary haematoxylin and eosin. 



Very pretty results are obtainable by using Mallory's polychrome 

 methylen blue and eosin ( 314). 



See also BABKIN, RUBASCHKIN and SSAWITSCH, Arch. f. Mikr. 

 Anat., Bd. 74 ; HELLY, ibid., Bd. 67 ; LANE, Amer. Journ. Anat. 

 vii, 1907, SAGUCHI, ibid., Vols. 26 and 28, and 713. 



