CHAPTER XXX. 395 



albumen ; pass through toluol, absolute alcohol, water, iodise, and 

 place in this brazilin solution for several hours : 



Phosphotungstic acid . . . . 1-0 grm. 



Distilled water ..... 100-0 c.c. 



Brazilin . . . . . . 0-05 grm. 



The brazilin is first dissolved in a small quantity of distilled water 

 by the aid of heat and added to the phosphotungstic acid solution. 

 This solution goes bad after three days. After staining in the 

 brazilin, wash in water, and place for five minutes in this mixture : 



Phosphomolybdic acid .... 1-0 grm. 



Wasserblau . . . . . . 0-2 ,, 



Water ....... 100-0 c.c. 



Wash rapidly in water, dehydrate in absolute alcohol, clear in 

 toluol, and mount in balsam. Cytoplasm stains blue to lilac, 

 nuclear chromatin deep red, contents of thyroid vacuoles sky blue, 

 and colloid droplets of Hiirthle deep blue to deep red. 



804. Pancreas. Most of the techniques given under the heading 

 of " Mitochondria " and " Golgi apparatus," etc. ( 673712) give 

 important results with the zymogen granules of the pancreas. The 

 methods of Bensley-Cowdry ( 686), Regaud ( 685), Benda ( 683), 

 and Schridde ( 687), all apply here. For the Golgi apparatus 

 Cajal's formalin silver nitrate method may be used ( 847). 



BENSLEY'S Neutral Red Method (Amer. Journ. Anat.,xii, 1911- -12). 

 -Animal killed by bleeding ; a cannula introduced into aorta and 

 a solution of neutral red in isotonic salt solution, containing 1 in 

 15,000 neutral red, is injected. Immediately after the pancreas has 

 assumed a faint rosy tint a part of the organ is removed the islets 

 of Langerhans stain intense yellow red, the rest faint rosy-pink. In 

 a short time after mounting the islets remain the only stained 

 elements, owing to bleaching in the acini. Method applicable to 

 the counting of the islets of Langerhans. 



Janus Green Method. See 702. Islets deep blue on a red 

 background. 



Pyronin Method for Ducts. Inject a 1 in 1,000 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 XVI. 



GRAND-MOURSEL and TRIBONDEAU (C. R. Soc. BioL, liii, 1901, 



