ESTIMATION OF AMOUNT OF HEMOGLOBIN. 157 



exposed to direct sunlight ; look at them by the light 

 which is reflected from this paper, and add water from 

 the pipette belonging to the dropping bottle, drop by 

 drop, until the colour in the two tubes is exactly the 

 same. Read off the height of the column of diluted 

 blood ; this gives the percentage amount of haemoglobin. 



Oliver's haemoglobinometer differs from that of 

 Gowers' in that the degree of dilution is constant 

 and the colour of the diluted blood is read off by 

 comparison with a series of carefully graduated stan- 

 dards. It consists of (i) a capillary glass tube with 

 thick walls and ground ends, one of which is flat and 

 the other pointed ; this tube is mounted in a metal 

 handle, the other end of which serves as a stirrer 

 (fig. 27, c) ; (2) a small cell with an opaque white 

 bottom, and provided with a cover-glass which has 

 a slight bluish tint (e) ; (3) a series of twelve coloured 

 glass discs mounted over an opaque white back- 

 ground (a) ; (4) certain small pink glass discs used 

 as riders ; (5) a short glass pipette with an india- 

 rubber nipple at one end and a short length of india- 

 rubber tubing at the other (d) ; the latter fits over the 

 pointed end of the capillary tube mentioned first ; and 

 (6) a small wax candle such as is used for Christmas 

 trees. A camera tube lined with a green material is 

 used to screen the eyes whilst the comparison is being 

 made. 



Method of use : Prick the patient in the usual way. 

 Apply the polished end of the capillary tube to the 

 drop of blood ; this will completely fill the tube, being 

 drawn up by capillary attraction. When quite full 

 wipe both ends of the tube with the fingers and apply 

 the end of the glass pipette (previously filled with 

 water) to the pointed end of the capillary tube. Now 



