OONNliOTlVK TISKUKS. 351 



These methods give a specific metachromatic stain of Mast- 

 zelleu on a light ground. See also lor. rit., two other methods 

 demonstrating plasma cells at the same time. 



705. Other Methods for Plasma Cells and Mastzellen. — See, 

 riiter alios (in previous editions) Pappenhbim, Virchow's Arch., clxvi, 

 1901, p. 4-27; Bbkgonzini, Anat. Anz., 1891, p. 596; Scheiddb, Anat. 

 Uefte, xxviii,, 1905, p. 698 ; Maximow, Arch. mik. Anat., Ixvii, 1906, 

 p. 686 ; ScHAFBBK, Gentrabl. Phys., xxi, 1907, p. 261 (fixation in absolute 

 alcohol or 2 parts alcoliol to 1 of formol, staining for half an hour in 

 methylen blue, thionin or toluidin bhie, in 70 per cent, alcohol with 

 1 per cent, of HCl) ; Ranvieb, C. B. Acad. Sci., 1890, p. 165 (his 

 "Clasmatocytes": fix with osmium, stain with aqueous methyl violet 6B). 



Fat. 



706. Fat and Lecithin. — According to Loiskl (C. R. Soc. 

 Biol., \v, 1903j p. 703) lecithin is much less soluble than 

 neutral fats in turpentine or ether, and in general much 

 more stainable. To demonstrate lecithin^ he advises as 

 follows : After fixation^ mordant the tissues with alum ; leave 

 them as little as possible in alcohol j dehydrate with acetone, 

 ether, or benzin ; stain with hsematoxylin, gentian, methyl 

 green, toluidin blue, Saurefuchsin or orange G, which stain 

 lecithin strongly, whilst leaving fat unstained. 



Dei'landee {Journ. Anat. Phys., 1904, p. 80) fixes in formol 

 of 4 per cent, and brings into acetone, in which fat is dissolved, 

 but not lecithin, which can then be stained by osmium. 



See also Ciaccio, Arch. Zellforsch., v, 1910, p. 235 ; and 

 FiscHLEE, Zeit. iviss. Mili., xxii, 1905, p. 262. 



707. Mounting Fat. — Onmicated fat can generally be mounted 

 in balsam without special precaution. For delicate fats, 

 it may suffice to avoid absolute alcohol and essences as much 

 as possible, and mount direct in (ilcohol halsam or eiqmral, 

 or clear with codar oil, which has little solvent action. For 

 very delicate fats it may be necessary to avoid alcohol of 

 more than 70 per cent., or avoid it altogethe)-, and mount in 

 glycerin or lovulose. 



708. Removal of Fat. — Fat can generally be dissolved out 

 by alcohol, ether, or chloroform and the like. Osmicated 



