536 



METHODS AND FORMULAS 



MS21.2-MS22.0 



21.2 Miller 1923 763, 25 :77 



KEAGENTS REQUIRED: A. 4% citric acid; B. 1% gold chloride; C. 30% formic acid 

 method: [fresh tissue] -^ A, 20-30 mins., in dark -» rinse -> B, 20-30 mins., in dark -» 

 C, 2 days -^ wash -^ glycerol 



21.2 Nikiforoff see DS 21.213 Nikiforoff 1896 



21.2 Ranvier 1880 17510, 80:456 



REAGENTS REQUIRED: A. Ranvier 1880 MS 21.1; B. 20% formic acid 

 method: .4, 20 mins. to 2 hrs. -^ B, in dark until reduced 

 note: Flechsig 1884 1739, 463 substitutes 10% sodium hydroxide for B above. 



21.2 Ranvier 1889 Ranvier 1889, 813 



reagents required: A. fresh filtered lemon juice; B. 1% gold chloride; C. 0.2% acetic 



acid; D. 20% formic acid 

 method: [fresh tissue] — » A, until transparent -^ rinse -^ B, 20 mins. -^ rinse — > C, in 

 light, 24 to 48 hrs. -^ examine -^ [if successful render permanent by] — > D, 48 hrs. in 

 dark 



21.2 Rufini test. 1933 Cajal and de Castro Cajal and de Castro 1933, 348 



REAGENTS REQUIRED: A. 20% formic acid; B. 1% gold chloride; C. 1% potassium ferro- 



cyanide 

 method: [fresh tissue] —* A, till translucent — ♦ wrap in cloth — » B, in dark, 20-30 mins. 

 -^ A, in dark, 24 hrs. — » C, if overstained, till differentiated -^ wash — > glycerol 



21.2 Stoehr 1894 test. 1907 Bohm and Oppel Bohm and Oppel 1907, 258 



REAGENTS required: A. MS 21.1 stoehr 1894; B. 20% formic acid 

 method: [fresh muscle] — »• A, 45 mins. -^ wash -^ B, in light, 36 hrs. 



MS 22 METHODS USING GOLD IN COMBINATION WITH MERCURY 



These methods are mostly used for the 

 demonstration of neuroglia, particularly 

 oligodendroglia and microglia. They ap- 

 pear at first sight to be simple, but are 

 actually more difficult to use than are the 

 silver techniques developed for the same 

 purpose. There appears to be no criterion 

 for success, though this may be rendered 

 the more likely by the use of pure reagents 

 and the most rigorous attention to chem- 

 ical cleanliness of the glassware employed. 

 Nothing appears to be known of the the- 

 ory lying behind these stains. 



MS 22.0 Typical Example 



Demonstration of protoplasmic 



neuroglia in the cerebral 



cortex by the method 



of Cajal 1916 



This is a deceptively simple technique 

 which is unlikely, in inexperienced hands, 

 to yield as good results as are the silver 

 methods (MS 31.22, 33.22, 34.22) more 

 commonly employed for this purpose. It 

 is essential that the reagents, the distilled 

 water, and the glassware emploj'ed be pre- 



pared as though one were engaged in a 

 critical analj^sis. For the first step, secure 

 a Uving or freshly killed rabbit and the 

 solution of ammonium bromide fisted in 

 Chapter 24 as AMS 11.1 CajallGlB. This 

 solution must be prepared with reagent 

 quality materials throughout, including 

 the formaldehyde ; and the bottle in which 

 it is placed must be chemically clean. It is 

 desirable to place in the bottom of this 

 bottle a layer of about half an inch, either 

 of fat-free absorbent cotton or of a fine 

 glass fiber. 



The freshly killed rabbit is tied face 

 down on a board, the upper surface of the 

 head skinned, and the frontal and parietal 

 bones removed with forceps, particular 

 care being taken not to break the blood 

 vessels of the meninges. All extraneous 

 blood should be removed with a gentle 

 washing in either triple-distilled water or 

 with a normal saline made with triple- 

 distilled water. The surface of the brain 

 is then flooded with a relatively large 

 quantity of the ammonium bromide-for- 

 maldehyde solution, which acts as'a hemo- 

 static agent during the removal of the 



