ESTIMATION OF AMOUNT OF H4ZMOGLOBIN. 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 
HAMOGLOBIN. 
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 Gowers’, 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 hzmoglobinometer 
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 
