12 



METHODS OF EXAMINATION 



The error in use does not amount to more than ten per cent. 

 This instrument is sufficiently accurate for ordinary clinical work. 

 Gower's hemoglobinometer. This instrument consists of two 

 sealed glass tubes containing glycerin tinted with picrocannine 

 to represent the tint of a one per cent, solution of normal blood. 

 One of these tubes, marked with a white dot, is for use by daylight 

 and the other, marked by a black dot, for use by candle light. 

 Besides these tubes there is a tube of similar size graduated into 

 140 parts, each of which contains 20 cmm., a capillary pipette 

 marked at 20 cmm. and a block for holding the tubes when making 

 the comparison. 



Method of using. The blood is drawn into the pipette to 

 the mark 20 cmm., the outside wiped off and the contents expelled 



into the diluting tube, 

 which should contain a lit- 

 tle distilled water. The 

 inside of the pipette is 

 rinsed out by alternately 

 drawing in and expelling 

 water from the tube. 

 While expelling blood or 

 water from the pipette the 

 point of the pipette should 

 be raised slightly above the 

 surface of the water in the 

 tube to avoid blowing bub- 

 bles. Rinsing the pipette 

 also serves to mix the 

 blood with the water. 

 After rinsing the pipette, 

 water is added gradually 

 to the diluted blood in the tube until it is of the same tint as the 

 standard tube. The blood and water should be mixed by closing 

 the tube with the thumb and inverting it several times. Do not 

 shake the tube and produce bubbles in it as bubbles will render it 

 difficult to read the amount. Comparison is made by placing 

 both the standard tube and the diluted blood in the block and 

 viewing them by reflected light. It is better to hold a paper or 

 other white background behind the tubes and let the light fall 



FlG. 7. Gower's hemoglobinometer. 



