1 62 



PRACTICAL HISTOLOGY. 



[X. 



various elements fibrous and cellular are usually brought distinctly into 

 view (Ranvier}. 



(ii.) An excellent plan is to inject picro-carmine interstitially, and to leave 

 the bulla several hours before snipping out a small part of it and mounting 

 it in formic glycerine, hi this preparation connective-tissue fibres with con- 

 strictions at intervals are frequently seen. 



(iii.) A fibre may be stained with acid haernatoxylin and mounted in gly- 

 crrine (p. 69). 



14. Coarsely Granular Cells (" Mastzcllen " of Ehrlicti). Place part of the 

 omentum of a young rabbit or the fat from around the kidney of a rat or 

 rabbit in a watery solution of gentian-violet, to which a filtered watery solu- 

 tion of aniline-oil has been added. Heat the 

 whole in a capsule until the vapour begins to 

 rise, and allow it to cool. 



After staining for twenty-four hours, remove the 

 tissue and wash it in acid alcohol until most of the 

 blue is gone. Dehydrate it in absolute alcohol, 

 dear with xylol, and mount it in xylol-balsam. 



(H) Search for a blood-vessel, and along its 

 course will be found large oval cells crowded 

 with numerous granules stained blue (fig. 127). 

 These cells are found also apart from the blood- 

 vessels. 



15. Gentian-Violet and Carmine Preparation. 

 The preparation may be double stained, thus : 

 After washing in acid alcohol, stain the prepara- 

 tion in lithium-carmine for a few minutes, and 

 again extract with acid alcohol. Mount as before 

 in balsam. Observe the granules of the cells, 

 blue as before, the nucleus red. All the other 

 nuclei in the field are now red. 



16. Clasmatocytes. Ranvier 1 has given the name clasmatocyte (tc\d(ru,a, 

 fragment, KVTOS, cell) to cells which can be seen in thin connective-tissue mem- 

 branes of vertebrates. In Triton cristatus these cells may be I mm. in length. 

 Stretch a membrane, e.g., the omenturn of a mammal or mesentery of a small 

 reptile on a slide. Fix its elements by dropping on it a drop of I per cent, 

 osmic acid, and then stain it with methyl-violet-BBBBB (i part) dissolved 

 in distilled water (10 parts). Examine the preparation in the fluid or in 

 water. Large branched cells are seen stained of 

 a bluish tint. At the extremities of the branches 

 are small islands or granulations similarly tinted, 

 and it is for this reason Ranvier has given them 

 this name. 



17. Cell-Spaces in Areolar Tissue (H). From 

 a freshly-killed rabbit snip out a small piece of 

 the subcutaneous tissue as free from fat as pos- 

 sible. Spread it upon a dry slide, and drop on it 

 FIG. 128. Cell-Spaces in Areo- from a pipette a half per cent, solution of silver 

 lar Tissue. Silver nitrate, nitrate. Allow the silver to act for ten to twelve 

 minutes, remove it, cover the film with glycerine 



and expose it to light. It rapidly becomes broun. It is better to use con- 

 nrctive-tissue from a calf, but the layer used must not be too thin. 



(a.) If successful, note a brownish ground the cement substance and in it 

 clear branched spaces corresponding in shape to the fixed connective-tissue cor- 

 puscles. These are the cell-spaces (fig. 128). 



1 Comptcs Rcndus, vol. 110, p. 165, 1890. 



FIG. 127. Coarsely Granular 

 Cells, the " Maslzellen " of 

 GcTinnn authors, from Rat. 

 /. Fat cells ; v. Vein ; in. 

 " ^lastzelleii.' 



