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ESSENTIALS OF CHEMICAL PHYSIOLOGY 



more largely, the oxyhsemoglobin is in excess ; if to a smaller extent, it is 

 less than normal. If the blood has, for instance, to be diluted up to the 

 graduation 50, the amount of haemoglobin is only half what it ought to be — 

 50 per cent, of the normal— and so for other percentages. 



The instrument only yields approximate results, but is extremely useful 

 in clinical observations. 



Von Fleischl's Haemometer. — The apparatus (fig. 67) consists of a stand 

 bearing a white reflecting surface (S) and a platform. Under the platform is 

 a slot carrying a glass wedge stained red (K) and moved by a wheel (R). 

 On the platform is a small cylindrical vessel divided vertically into two com- 

 partments, a and a! . 



Fill with a pipette the compartment a' over the wedge with distilled 

 water. Fill about a quarter of the other compartment {a) with distilled 

 water. 



Fi(i. 67. — Fleischl's ha3mometer. 



Prick the finger and fill the short capillary pipette provided with the 

 instrument with blood. Dissolve this in the water in compartment a, and 

 fill it up with distilled water. 



Having arranged the reflector (S) to throw artificial Ught vertically 

 through both compartments, look down through them, and move the wedge 

 of glass by the milled head (T) until the colour in the two is identical. 



Read off the scale which is so constructed as to give the percentage of 

 haemoglobin. 



Dr. Oliver's Hsemoglobinometer. — This method consists in comparing a 

 specimen of blood suitably diluted with water in a shallow white palette, 

 with a number of standard tests very carefully prepared by the use of 

 Lovibond's coloured glasses. The capillary pipette c (fig. 68) is first filled 

 with blood obtained by pricking the finger. This is washed with water 



