ESTIMATION OF AMOUNT OF HEMOGLOBIN. 155 



apparatus is absolutely dry. You can tell when this has 

 happened by the fact that the ball inside the bulb will 

 emit a clear ringing sound when the pipette is shaken. 

 It is useless to attempt to dry the tube by blowing 

 through it from the mouth. 



If blood has coagulated within the apparatus it must 

 be digested out. Fill the whole with an artificial 

 digestion fluid (pepsin and very dilute hydrochloric 

 acid) and place it in a test-tube of the same fluid in a 

 warm place for twenty-four hours. Then try to clean it 

 as before and repeat the digestion if this is impossible. 



ESTIMATION OF THE AMOUNT OF 

 HEMOGLOBIN. 



There is no absolutely satisfactory apparatus for the 

 estimation of the amount of haemoglobin in the blood at 

 present on the market. Those which are chiefly used 

 in this country are Cowers', and Oliver's. Gowers' is 

 the simplest and by far the cheapest form ; the neces- 

 sary manipulations are very easily learnt, but it is not 

 easy to take exact readings. Indeed, the margin of 

 error is very considerable. Oliver's hsemoglobinometer 

 is a little more difficult to use, but it is somewhat easier 

 to read ; its price prevents it coming into universal 

 use. It is to be recommended where absolute results are 

 required ; for clinical purposes when we wish to see 

 whether a patient is or is not improving under treatment 

 Gowers' will answer quite well. 



It consists of two tubes mounted in a small stand. 

 One of these tubes is filled with a jelly tinted to 

 represent the colour of normal blood of a certain 



