234 CLINICAL BACTERIOLOGY AND H^MATOLOGY 



case mentioned above, we had to add a rider marked 5 to the 

 standard to bring about an exact match, the percentage 

 amount of haemoglobin in the blood would be 55. 



It is an advantage to place cell and standards side by side 

 rather than one above the other, for the upper and lower 

 portions of the retina differ in sensitiveness to colour, whilst 

 the sides do not. 



CLINICAL APPLICATIONS 



1. It is impossible to estimate even the presence of anaemia, 

 to say nothing of its degree, without an examination of the 

 amount of haemoglobin. I have been repeatedly asked by 

 highly skilled clinical observers to examine cases presenting 

 all the appearances of anaemia in whom the blood has been 

 in every respect normal. The examination, therefore, should 

 be made in all cases of supposed anaemia, and the diagnosis 

 should not be considered as established until this has been 

 done. 



The recognition of the degree of anaemia is advisable, in 

 that it permits the effect of treatment to be watched and 

 ineffective remedies to be discontinued. It also affords a 

 guide as to prognosis, for if a patient's amount of haemo- 

 globin increases during, say, the first week of treatment, a 

 good prognosis may be given, although there are no other 

 signs of improvement, and some idea as to the time neces- 

 sary to effect a complete cure may be obtained. 



2. Apart from an ordinary anaemia, the estimation of the 

 haemoglobin may give an important clue as to the presence 

 or absence of other diseases. For instance, in severe sepsis 

 there is usually a very marked and rapid fall in the amount 

 of haemoglobin, due to the destruction of the red corpuscles 

 by the toxin of the infective organisms. This is especially 

 valuable in that it occurs in severe infections in which the 

 leucocytes often do not undergo characteristic alterations (see 

 p. 279). Thus, if an increasing anaemia is found in a patient 

 during the puerperium, it points strongly to puerperal fever, 

 and the prognosis is bad, assuming, of course, that there is 

 no haemorrhage or other cause of anaemia. 



In interpreting the results of this examination you must 

 remember that when there is severe diarrhoea, sweating, 



