PART III 



CYTO-DIAGNOSIS 



CYTO-DIAGNOSIS is the diagnosis of the cause of exudates by 

 the recognition of the cells which they contain. It may be 

 regarded as a branch of haematology, though the cells which 

 are encountered are not wholly those of the blood. Its 

 results are less certain than those obtained by the recognition 

 of the organism (if any) present in the exudate, but are often 

 easier to obtain; they are more certain than those obtained 

 by an examination of the blood, as easy to obtain, and in most 

 cases very much easier to interpret. As the methods are very 

 simple and require no special apparatus (though a centrifuge 

 is a very great help), they are within the reach of all practi- 

 tioners, and a cytological examination should always be made 

 when fluid is withdrawn from the chest, abdomen, etc., 

 whether for diagnosis or treatment. 



METHOD OF COLLECTING THE CELLS. No description will 

 be given of the methods of obtaining the exudate, as those 

 which are not in general use have been dealt with already. 



If the fluid does not clot spontaneously, it is only necessary 

 to centrifugalize a portion (as much as the tube will hold 

 about 10 c.c.J for five minutes or so, and then to invert the 

 tube and pour off as much of the supernatant fluid as will 

 come away. The sediment will be left, and a drop or two of 

 fluid will run back down the sides of the tube. These must 

 be thoroughly mixed in with the deposit so as to form a 

 uniform emulsion. 



In the absence of a centrifugal machine, allow the fluid to 

 stand for twelve hours or so to settle, adding a crystal of 

 thymol to prevent decomposition. Then remove some of 

 the deposit with a pipette; you cannot invert the tube in this 

 case, as the sediment is not so compact, and will pour out. 



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