18G 



DETERMINATION OF HAEMOGLOBIN. 



[BOOK I. 



degree at which the colour of the dilution ceases to be deeper than 

 the standard, and also that at which it is distinctly paler. The degree 

 midway between these two will represent the haemoglobin percentage. 

 The instrument is only expected to yield approximate results, 

 accurate within two or three per cent. It has however been found of 

 much utility in clinical observations 1 . 



FIG. 37. DK GOWERS' APPAKATUS FOE THE CLINICAL ESTIMATION OF HAEMOGLOBIN. 



E, block of wood with two holes, to serve as a stand for the tubes C and D. 

 D, tube containing glycerine- jelly treated with picro-carmiue. 



C, graduated tube in which the blood is diluted with water. 



B, capillary pipette marked so as to allow of 20 cubic millimetres of blood being 

 measured. 



F, lancet-shaped needle for puncturing the finger. The point of the needle may be 

 protruded to a greater or less extent, so as to produce a more or less deep puncture. 



A, bottle for distilled water. 



8. By the 

 determina- 

 tion of iron 

 contained in 

 the ash of the 

 blood. 



As it is known that pure haemoglobin contains 0'43 

 per cent, of Fe, and as all the iron in the blood exists in 

 haemoglobin, we may calculate the amount of this con- 

 stituent if we know how much iron is contained in the 

 ashes of a known volume or weight of blood. 

 With this object about 100 grammes of blood are evaporated to 

 dryness in a platinum basin, and then ignited, care being taken not 

 to lose any portion of substance by incautiously heating, which would 

 cause the burning organic matter to froth over. The ash is cooled 

 and boiled with 10 or 20 c.c. of pure hydrochloric acid diluted with 

 its own volume of water, and the extraction is repeated. The solution 

 of ferric chloride in then reduced by the action of metallic zinc, and 



1 Dr Gowers' apparatus is sold, under the name of Haemoglobinometer, by Mr 

 Hawkesley, Surgical Instrument Maker, 300, Oxford Street, London, W. 



