538 METHODS AND FORMULAS MS 22.1-MS 22.21 



If the preparations are required only for for this purpose. This is no better than 



temporary examination, they may be, at water from the point of view of removing 



this point, dehydrated and cleared, but an excess of the fixative, but has the ad- 



the stain itself is still light-sensitive and vantage of commencing the process of 



it is necessary to fix the sections if they dehydration. 



are to be mounted in balsam. Cajal him- After the sections have been adequately 

 self recommends an acid-thiosulfate solu- washed they should be removed one by 

 tion, the formula for which is given in one from the washing solution, placed on a 

 Chapter 24 as AMS 24.1 Cajal 1913. The clean shde, covered with filter paper, and 

 sections should be treated in a large vol- blotted to remove as much of the alcohol 

 ume of this solution for five or ten min- as possible. They may then be dehydrated 

 utes. The time of apphcation is not criti- by dropping alcohol on them from a pipet 

 cal, and it is better to err on the side of too or wash bottle, and cleared in any satis- 

 long apphcation than too short. The solu- factory clearing agent before mounting 

 tion cannot be used twice and should be in balsam. 



thrown away after each batch of sections These preparations at the best are only 



have been passed through it. The fixing moderately permanent, and should never 



solution must, of course, itself be removed be exposed to bright light for long periods 



by thorough washing and Langeron (Lan- of time, 

 geron 1942, 653) recommends 40% alcohol 



22.1 Staining Solutions 



22.1 Cajal 1916 21344, 14:155 



formula: water 100, mercuric chloride 0.7, gold chloride 0.14 



preparation: Dissolve mercuric chloride in 15 water at 70-80°C. Dissolve gold chloride 

 in 15 water at room temperature and add to mercuric chloride. Dilute mixture to 100. 



22.1 Raileanu 1930 6630, 104:285 



formula: water 100, mercuric chloride 1.6, gold chloride 0.16 

 preparation: see Cajal 1916 (above) 



22.1 Ziehen 1891 15058, 10:65 



formula: water 100, mercuric chloride 0.5, gold chloride 0.5 

 preparation: see Cajal 1916 (above) 



22.2 Neurological Methods 



22.21 nerve cells and processes 



22.21 Apathy 1893 23632, 10:349 



reagents required: A. 1% formic acid; B.\% gold chloride 

 method: [paraffin sections of material fixed in F 1300.0000 Apdthy 1893] -^ wash — * A, 



1 min. -^ B, 24 hrs. -^ blot -^ A, evenly illuminated from both sides, till reduction 



complete -^ balsam via usual reagents 

 note: Lee 1905, 254 substitutes 0.1% formaldehyde for the second usage of A above. 



22.21 Lee 1905 see MS 22.21 Apathy 1893 (note) 



22.21 Nabias 1904 6630, 66 :426 



reagents required: A. ADS 12.2 Gram 1884; B. 1% gold chloride; C. sat. sol. aniUne 

 method: [sections of material fixed in mercuric chloride] —> A, till yellow —>■ rinse — ^ B, 



5 mins. -^ rinse —>■ C, till differentiated 

 recommended for: ganglia of invertebrates. 



22.21 Ogawa 1913 1798, 29 :248 



reagents required: A. \% gold chloride; B. \% formic acid 



method: [smears, fixed in F 3000.0000 or F 3000.0010 mixtures] -^ wash -> A, 24 hrs. -^ 

 wash -^ B, in direct sunlight, till purple -^ balsam, via usual reagents 



