F 0000.1080-F 1000.0000 FIXATIVES 193 



0000.1080 Fornialdehyde-{other inorganic acids) 



0000.1080 Cohen 1934 20540b, 9:104 



formula: water 225, metaphosphoric acid 9, 40% formaldehyde 25 



0000.1200 Formaldehyde-acetaldehyde 



0000.1200 Besta 1910 766,36:477 



formulas: a. water 200, 40% formaldehyde 50, acetaldehyde 5; B. water 250, am- 

 monium molybdate 10 

 method: [fix A, 2 days] — * distilled water, 24 hrs. with frequent changes —> B, 2 days 



0000.1300 Formaldehyde-acetone 



0000.1300 Bing and Ellermann 1901 1739, 3:260 



formula: 40% formaldehyde 25, acetone 225 



0000.4000 (Othek Modifiers) 



0000.4000 MacFarland and Davenport 1941 20540b, 16:53 



formula: water 112, 95% ale. 112, chloral hydrate 12.5, formamide 25 



0000.4010 {Other modifier s)-acetic 



0000.4010 Grapnuer and Weissberger 1933 23833, 102 :39 



formula: methanol 50, dioxane 200, paraldehyde 5, acetic acid 12.5 



F 1000 OSMIC ACID IN ALL COMBINATIONS 



1000.0000 OsMic Alone 



It cannot be too strongly emphasized that osmic acid is a dangerous material to handle. 

 The vapor causes the death of tissues with which it comes in contact almost instantly and, 

 indeed, it may be employed for fixation in the vapor phase. This vapor, applied to the cornea 

 of the eye or to the membranes of the nose, can cause the most grave damage in a short 

 space of time. Since osmic acid is very easily reduced in the presence of almost all organic 

 material, solutions are difficult to keep. The writer prefers the addition of about .01% of 

 potassium permanganate. This gives a pink color, which may easily be judged by the eye, 

 so that the oxidation of the permanganate can be corrected by the addition of a few drops 

 of a stronger solution. The product of the reduction, which is a dead black in color, appears 

 to be some of the lower oxides. These lower oxides may again be easily oxidized (bleached) 

 and it is customary to use various mixtures of hydrogen peroxide (see Chapter 19, AF 31.1 

 Overton 1890) for the purpose, but the specimen must be washed thoroughly or the oxides 

 will be reprecipitated on the tissues. Osmic acid alone is rarely used save for very small 

 objects. It has the great advantage that it gives a faithful picture of cytological detail. Olney 

 1953 (Turtox News, 31 :29) states that nitric acid may be substituted for osmic acid in 

 fixative formulas. 



1000.0000 Bizzozero 1885 1789a, 102 



formula: water 250, osmic acid 0.625, sodium chloride 0.19 



1000.0000 Ewald 1897 23354,34:257 



formula: water 250, osmic acid 0.375, sodium chloride 1.25 



note: The above is recommended for amphibian and reptilian blood; for mammals the 

 NaCl is increased to 0.65%. 



1000.0000 Mann 1894 23632, 11 :479 



formula: water 250, osmic acid 2.5, sodium chloride 1.875 



1000.0010 Osmic-acetic 



These are excellent mixtures, and are probably as good as the osmic-chromic-acetic more 

 usually recommended. The rapid fixing and hardening power of the osmic acid counteract.s 

 the swelling properties of the acetic. These fixatives ciin be recommended both for cytological 

 and nuclear fixation. 



