MICRO - INCINERATION 



Micro-incineration is a technique employed to ascertain the 

 relative positions occupied by inorganic salts in fixed tissues, and 

 the total distribution of these mineral substances in cells and 

 tissues. 



There are two methods of fixation, neither of which is perfect, 

 namely; (a) Freeze- dry and (b) Chemical fixation. The first 

 method requires reagents and apparatus which are not normally 

 available in the average laboratory; also the method is exceedingly 

 laborious and time consuming: there is a certain element of risk 

 of injury to the operator who may not be accustomed to handling 

 such substances as liquid nitrogen at a temperature of — i7o°C. 

 Moreover, it is extremely doubtful if the elaborate *' Freeze-Dry " 

 method offers any more accurate results than those obtained by 

 the relatively simple chemical fixation method. 



By employing either method the total mineral distribution can- 

 not be determined with an error of less than, say, io% as all 

 minerals will not survive the incineration processes, and it is, 

 therefore, proposed to describe here the more simple and straight- 

 forward chemical method of fixation which can be carried out in 

 any laboratory. 



Solution required: 



Absolute alcohol . . . . . . 90 ml. 



Formaldehyde 40% . . .. .. 10 ml. 



Note: It is best to use freshly distilled alcohol. On no account 

 must the alcohol have been dried with copper sulphate nor any 

 other mineral reagents. The formaldehyde must not have been 

 treated with calcium carbonate, buffer salts or any other mineral 

 reagents. It is essential that all the reagents used must be free 

 from, and remain free from, dust and mineral matter; this refers 

 also to the xylol and the paraffin wax. All aparatus used must be 

 scrupulously clean, washed out with several lots of distilled water, 

 partially dried with absolute alcohol, and in all cases, where at all 

 possible, finally dried with a clean dust-free cloth. 



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