116 



FALLACIES AND PUZZLES IN HLOOD EXAMINATION 



if one employs a platinum loop to transfer a drop of blood to a slide and does not take care 

 to see that it has cooled sufficiently after sterilisation in the Hame. The glow may 

 have faded from it but it still may be too hot. The same thing may occur if a finely drawn 

 glass pipette is used immediately after it lias been made, so it is well to be careful 

 in these directions. 



? ;^ Ti ' — A t I y R V :■ H I 1 '' r ■ ; .1 

 Tbfi ctaalo, tlutnb-b«ll. droplet, nod fllameDt phenomena in fowl's blood and butnan blood un necn by Uie dark-fleld method 



In part after N'uttall and Gniham-Sroith 

 Not drawn tfl scale 



In the fresh blood of man the platelet is not very likely to be a source of fallacy, but it 

 is said that a platelet lying on a red corpuscle may simulate a malarial plasmodium and is 

 to be distinguished by the fact that it is less opaque, has a granular look and is less 

 refractive. Moreover it often presses the haemoglobin of the red cell away from under it 

 and so looks as though surrounded by a pale area (Plate V., fig. 9). It may here be 

 pointed out that in the case of any doubtful body lying on, or apparently in, a red cell, 

 help will be obtained by altering the illumination of the field. A dull light is responsible 

 for many errors and brighter illumination may even change the colour of a dark object 

 from black to a bright crimson. By touching the edge of a cover-glass with a needle 



