416 BLOOD AND GLANDS 



decanting and discarding the washings. When the precipitate is 

 thoroughly washed, add 100 c.c. doubly distilled water and dis- 

 solve half to three-quarters of it with ammonia, added drop by 

 drop. Filter the supernatant fluid with an opaque bottle and 

 store in dark. This stock A9(Co3)2 solution keeps two to four 

 weeks. 



The bath is the silver carbonate solution 5 c.c, distilled water 

 5 c.c, and pyridin 2 to 3 drops. The porcelain dish in which the 

 sections are heated should not be washed after use as the silver 

 coating improves impregnation. 



900. Spleen. For hsematological studies this is best fixed in 

 Helly's or Maximow's fluids for not more than six hours. Thin 

 pieces are j^referable and perfusion is advisable. 



KuLTSCHiTZKY {Arch. mik. Anat., xlvi, 1895, p. 675) studies 

 the musculature in sections (of material from liquid of Miiller) 

 stained for a day or more in a solution of lakmoid in ether and 

 mounted in balsam. 



For elastic fibres he puts sections for half an hour or a day into 

 a mixture of 800 parts 96 per cent, alcohol, 40 parts 1 per cent, 

 solution of carbonate of potash, 2 parts Magdala red, and 1 part 

 methylen blue. 



For the blood vessels he puts sections of Miiller material for a 

 few minutes into a solution of 1 or 2 parts of Saurerubin in 400 

 parts of 3 per cent, acetic acid, washes out in 2 per cent, acetic 

 acid, and after-stains in a similar solution of helianthin or wasser- 

 blau until the red only remains in the erythrocytes. 



Reticular (lattice) fibres are best studied by the various silver 

 techniques and their modifications. Foot {Anat. Rec, xxxvi, 

 1927, p. 99) fixes in Zenker directly or after perfusion, or in 

 10 per cent, neutral formol. He impregnates (a) by his modifica- 

 tion of the BiELSCHOWSKY technique {Journ. Lab. and Clin. Med., 

 ix, 1924, p. 777), (b) by his modification of Hortega's silver 

 ammonium carbonate technique {Arch. Path., iv, 1927, p. 36), 

 and (c) by his modification of Achucarro's silver tannate method 

 {Arch. Path., iv, 1927, p. 211). The original papers should be con- 

 sulted. 



Probably the simplest and most successful of the silver tech- 

 niques for reticular fibres is that recently devised by Wilder 

 {Amer. Journ. Path., xi, 1935, p. 817). Tissues are fixed in 10 per 

 cent, formalin, acetic-Zenker or formol-Zenker. Tissues may be 

 imbedded in paraffin, celloidin or cut as frozen sections. Paraffin 

 sections are brought to water, celloidin sections are stained in 

 dishes before mounting, and frozen sections may be stained in 

 dishes or mounted on slides and attached with thin celloidin. 

 They are then treated as follows : — 



Pre-treatment. Place the sections in 0-25 per cent, potassium 

 permanganate or in 10 per cent, phosphomolybdic acid for one 



