540 METHODS AND FORMULAS MS 23.21 



tions should be as thin as possible, though der the low power of the microscope, it is 



the necessary structures can be seen in time to remove the sections, one at a time, 



sections as thick as 40 microns. These sec- to 0.1 % hydrochloric acid in 60% alcohol, 



tions should be washed in several changes where they may remain for a matter of 



of triple-distilled water, after preparation ten minutes. Immersion in acid of this 



by the class, and then placed, preferably concentration in alcoholic dilution does 



in glass-stoppered, chemicaUy clean bot- not cause much further reduction. After 



ties, in the gold-staining solution and left they have been thoroughly dehydrated to 



there overnight. If the class does not meet the extent possible in the 60% alcohol, 



on two successive days, it is probably bet- they should be removed and passed 



ter for the instructor to handle the whole through other watch glasses where they 



technique up to this point and to issue to are dehydrated and cleared by the ordi- 



the class the material in the gold-chloride nary reagents. The sections may then be 



solution. The sections are taken from the mounted in balsam. 



gold-chloride solution directly to the 0.5% Beginning students of microtomy are 

 hydrochloric acid, where they are rocked frequently so frightened of the metal- 

 gently backward and forward in a clean staining techniques that they ignore them 

 watch glass for a few minutes. This will completely, and the real value of this 

 reduce the gold and will be a useful lesson method is to provide each student of 

 to the class on the perils of over-reduction, such a class with a gold-stained per- 

 When the outhnes of individual nerve cells manent slide by a method which is very 

 within the ganglia are clearly visible un- nearly foolproof. 



23.1 Staining Solutions 

 (Vacant) 



23.2 Neurological Methods 



23.21 nerve cells and processes 



23.21 Ciaccio 1880 13495,10:301 



REAGENTS REQUIRED: A. 0.2% acetic acid; B. water 100, gold chloride 0.1, potassium 



chloride 0.1; C. 0.1% osmic acid 

 method: [fresh amphibian tendons] —> A, tUl transparent —> B, 5 mins. — * C, 1 day in 



dark and 3 hrs. in sunlight — » C, 24 hrs. -^ M 11 mountant 

 recommended for: nerve endings in amphibian tendons. 



23.21 Gerlach 1872 test. Lee 1905 cit. Strieker 1872 Lee 1905, 253 



reagents required: A. 1% ammonium dichromate; B. 0.01% gold chloride; C. 0.5% 



hydrochloric acid; D. 0.1% hydrochloric acid in 60% ale. 

 method: [fresh spinal cord] — > A, 15 to 20 days -^ wash -^ sections freehand, or by 



freezing technique -^ wash -^ B, 10 to 12 hrs. — > C, wash -^ D, 10 mins. —> balsam, 



via usual techniques 



23.21 Golgi 1880 13497, 32 :382 



REAGENTS REQUIRED: A. 2% potassium dichromate; B. 1% arsenic acid; C. 0.5% gold 



chloride 

 method: [fresh tissue]-^ A, 10 to 20 mins. -^ wash ^^ B, 10 to 20 mins. -^ rinse C, 



30 mins. — > wash — > B, in sunlight, until completely reduced -^ wash -^ glycerol 



23.21 Kerschner 1908 1780, 71 :522 



REAGENTS REQUIRED: A. F 1000.0030 Kerschncr 1908; B. 1% gold chloride; C. 25% 



formic acid 

 method: [fresh tissue] — > A, until brown -^ wash -^ B, 2-6 hrs. in dark —>■ rinse — > C. 

 12 hrs. in dark — > C, fresh solution, 24 hrs. in light — > glycerol or M 12 mountant 



23.21 Kolossow 1888 see MS 21.2 Kolossow 1888 



