XXXVIII.] FRESH TISSUES. 40 1 



26. Diaphragm. ('(.) Show its endothelial covering by means 

 of AgX0 3 , and (h) its lymphatics (p. 237). 



27. Adipose Tissue. One must demonstrate the cells (Lesson 

 XII.). 



(a.) Fresh, unaltered in normal saline, using either part of 



omen turn or fat-cells from under skin. Seal up the 



preparation with paraffin wax. 

 (ft.) Action of osmic acid. 

 (c.) Action of alcohol and ether to remove fats, and show 



empty envelopes. 

 (<L) Harden fat-cells in alcohol and stain in logwood to show 



nuclei. 

 (e.) Subcutaneous injection of silver nitrate (i : 500) to show 



general characters of cells. 



28. Granular Cells (" Mastzellen "). They occur in large 

 numbers in the omentum of the rat. Place a small part of the 

 omentum in a watch-glass containing aniline- water and 2030 drops 

 of a concentrated alcoholic solution of dahlia or gentian. Heat for 

 short time as directed in Lesson X. 14. Wash in distilled water 

 and then in acid-alcohol until nearly everything is decolorised 

 except the granular cells. The tissue may also be stained with 

 lithium-carmine. Mount in balsam. The nuclei of the cells are 

 red, and only the granules in the protoplasm of the granular cells 

 are blue. 



The mucous membrane of a dog's tongue hardened in alcohol and 

 treated in the same way shows numerous granular cells. 



29. Bed Marrow of Bone. Methods (p. 188). Use the ribs 

 and heads of long bones of guinea-pig. 



The dry cover-glass method is excellent. Dry them in flame of 

 spirit-lamp, or pass them three times through the flame of a Bunsen- 

 burner. Stain with eosin-glycerine and then with methylene-blue 

 or logwood. Many of the smaller cells will show eosinophile 

 granules. 



For studying the formation of the elements of the blood in red 

 marrow or other situations, the following method of Fok is good. 1 

 The red marrow or blood is "fixed" in the following fluid after it 

 cools: 100 cc. Miiller's fluid is heated with 2 grams of mercuric 

 chloride. Keep in a thermostat (2-3 hours) at 35 C. Harden in 

 alcohol, cut sections, and stain (1-3 minutes) with the following : 



Haematoxylin solution (Bohmers] ... 25 cc. 

 Safranin I per cent, watery-alcoholic solution . 20 ,, 

 Water loo ,, 



Then stain in weak picric acid. Xylol-balsam. 



1 Zeits.f. wiss. Mikrosk., ix., 1892, p. 227. 



2c 



